web综合案例

学习目标

目标1：能够说出数据库设计的三种常用范式

目标2：能够使用PD工具进行表结构设计

目标3：完成学科模块的业务开发

目标4：完成目录模块的业务开发

目标5：完成题目模块的业务开发

目标6：能够说出文件上传前台的三要素

目标7：能够完成题目选项模块的业务开发

1. 数据库设计

1.1 数据库设计范式

什么叫数据库设计范式？

范式：规范的形式，应用于各个行业的标准化

数据库设计中有5种范式，但是常用的分别是：第一范式（1NF）,第二范式（2NF），第三范式（3NF）

第一范式（1NF）：针对数据表中的列，列要具备原子性，不可再拆分

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如果数据表这样设计，籍贯这一列不具备原子性，因为数据可再次拆分，不拆分的话无法获取用户的州郡信息或县市信息，拆分之后如下：

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第二范式（2NF）：数据表要具备唯一主键，不存在多主键，使得每一行数据具有唯一性

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在如图所示的表中：没有哪一个字段（列）能唯一确定一条数据，要想唯一确定一条数据，需要两个或更多的字段，这就违反了第二范式，数据表不具备唯一主键而存在多主键。

那如何来解决呢？在表中加一个唯一主键列：id

第三范式（3NF）：不依赖非主键的字段及更深层次的依赖，使得每个字段都独立依赖于主键字段（独立性）

什么叫依赖：依赖，就是在一个表中，其中某个字段的值B可以由另一个字段值A来决定，那我们称字段B依赖字段A或字段A决定字段B

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在如图所示的表结构中：合计列=单价 X 数量，当然这中间还需要依赖商品编号来查询商品单价

总而言之，合计这一列，依赖了表中的非主键字段，以及非主键字段的更深层次的依赖，这表明合计这一列的数据是冗余的，因为我们完全可以通过计算的方式得到合计数据，而不需要在表中来存储。

反三范式：允许少量的数据冗余，提高查询的速度

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1.2 数据库设计工具

PowerDesigner：简称PD，是一款功能强大的建模软件，提供强大的元数据管理功能，可以帮助用户构建关键信息的全方位视图，创建多种类型的模型，包括概念数据模型，物理数据模型，面向对象模型等等，同时集成了数据管理，BI，数据集成和数据整合多种功能。

2. 学科模块快速开发

下面我们进行学科模块的快速开发：

（1）创建学科实体：com.itheima.domain.store.Course

public class Course {private String id;private String name;private String remark;private String state;private Date createTime;// getter/setter略
}

（2）创建dao接口：com.itheima.dao.store.CourseDao

public interface CourseDao {int save(Course course);int delete(Course course);int update(Course course);Course findById(String id);List findAll();
}

（3）从今日课程资料中找到dao层资源文件\CourseDao.xml，拷贝到项目src/main/resources/com/itheima/dao/store/下

当然这个地方可以将该目录下的所有映射配置文件都拷贝到该目录下，在做后续业务时就无需在拷贝了。

（4）创建业务层接口：com.itheima.service.store.CourseService

public interface CourseService {/*** 添加* @param course* @return*/void save(Course course);/*** 删除* @param course* @return*/void delete(Course course);/*** 修改* @param course* @return*/void update(Course course);/*** 查询单个* @param id 查询的条件（id）* @return 查询的结果，单个对象*/Course findById(String id);/*** 查询全部的数据* @return 全部数据的列表对象*/List findAll();/*** 分页查询数据* @param page 页码* @param size 每页显示的数据总量* @return*/PageInfo findAll(int page, int size);
}

（5）创建业务层实现类：com.itheima.service.store.impl.CourseServiceImpl

public class CourseServiceImpl implements CourseService {@Overridepublic void save(Course course) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();course.setId(id);//3.调用Dao层操作courseDao.save(course);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic void delete(Course course) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//3.调用Dao层操作courseDao.delete(course);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic void update(Course course) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//3.调用Dao层操作courseDao.update(course);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic Course findById(String id) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//3.调用Dao层操作return courseDao.findById(id);}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic List findAll() {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//3.调用Dao层操作return courseDao.findAll();}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic PageInfo findAll(int page, int size) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//3.调用Dao层操作PageHelper.startPage(page,size);List all = courseDao.findAll();PageInfo pageInfo = new PageInfo(all);return pageInfo;}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}
}

（6）创建servlet：com.itheima.web.controller.store.CourseServlet

// uri:/store/course?operation=list
@WebServlet("/store/course")
public class CourseServlet extends BaseServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}}private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//进入列表页//获取数据int page = 1;int size = 5;if(StringUtils.isNotBlank(request.getParameter("page"))){page = Integer.parseInt(request.getParameter("page"));}if(StringUtils.isNotBlank(request.getParameter("size"))){size = Integer.parseInt(request.getParameter("size"));}PageInfo all = courseService.findAll(page, size);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/course/list.jsp").forward(request,response);}private void toAdd(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/course/add.jsp").forward(request,response);}private void save(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象Course course = BeanUtil.fillBean(request,Course.class,"yyyy-MM-dd");//调用业务层接口savecourseService.save(course);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/course?operation=list");}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");Course course = courseService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("course",course);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/course/update.jsp").forward(request,response);}private void edit(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象Course course = BeanUtil.fillBean(request,Course.class,"yyyy-MM-dd");//调用业务层接口savecourseService.update(course);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/course?operation=list");}private void delete(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象Course course = BeanUtil.fillBean(request,Course.class);//调用业务层接口savecourseService.delete(course);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/course?operation=list");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}
}

（7）修改BaseServlet，添加CourseService

public class BaseServlet extends HttpServlet {protected CompanyService companyService;protected DeptService deptService;protected UserService userService;protected CourseService courseService;@Overridepublic void init() throws ServletException {companyService = new CompanyServiceImpl();deptService = new DeptServiceImpl();userService = new UserServiceImpl();courseService = new CourseServiceImpl();}
}

（8）创建/WEB-INF/pages/store/course目录，然后从今日课程资料中找到模块页面\course下的所有页面，拷贝到刚刚创建的目录下

（9）修改业务层的保存方法，添加创建时间的保存

@Override
public void save(Course course) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCourseDao courseDao = MapperFactory.getMapper(sqlSession,CourseDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();course.setId(id);//添加创建的时间course.setCreateTime(new Date());//3.调用Dao层操作courseDao.save(course);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}
}

（10）在修改时，我们的创建时间是不允许修改的，因此我们在dao层进行update操作是去掉对创建时间的修改，找到CourseDao对应的持久层映射配置文件CourseDao.xml中的update，去掉创建时间即可

update st_courseset name = #{name,jdbcType=VARCHAR},remark = #{remark,jdbcType=VARCHAR},state = #{state,jdbcType=VARCHAR}where id = #{id,jdbcType=VARCHAR}

（11）解决站点字符编码的问题，从今日课程资料中找到web层资源文件\CharacterEncodingFilter.java

然后创建一个包com.itheima.web.filters，然后把该文件拷贝到该包下

（12）启动项目进行测试

3. 目录模块

（1）创建目录实体：com.itheima.domain.store.Catalog

public class Catalog {private String id;private String name;private String remark;private String state;private Date createTime;private String courseId;private Course course;// getter/setter略
}

（2）创建dao接口：com.itheima.dao.store.CatalogDao

public interface CatalogDao {int save(Catalog catalog);int delete(Catalog catalog);int update(Catalog catalog);Catalog findById(String id);List findAll();
}

（3）拷贝dao映射配置文件：前面已完成

（4）创建业务层接口：com.itheima.service.store.CatalogService

public interface CatalogService {/*** 添加* @param catalog* @return*/void save(Catalog catalog);/*** 删除* @param catalog* @return*/void delete(Catalog catalog);/*** 修改* @param catalog* @return*/void update(Catalog catalog);/*** 查询单个* @param id 查询的条件（id）* @return 查询的结果，单个对象*/Catalog findById(String id);/*** 查询全部的数据* @return 全部数据的列表对象*/List findAll();/*** 分页查询数据* @param page 页码* @param size 每页显示的数据总量* @return*/PageInfo findAll(int page, int size);
}

（5）创建业务层实现类：com.itheima.service.store.impl.CatalogServiceImpl

public class CatalogServiceImpl implements CatalogService {@Overridepublic void save(Catalog catalog) {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();catalog.setId(id);//3.调用Dao层操作catalogDao.save(catalog);//4.提交事务TransactionUtil.commit(sqlSession);} catch (Exception e) {TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}}@Overridepublic void delete(Catalog catalog) {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//3.调用Dao层操作catalogDao.delete(catalog);//4.提交事务TransactionUtil.commit(sqlSession);} catch (Exception e) {TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}}@Overridepublic void update(Catalog catalog) {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//3.调用Dao层操作catalogDao.update(catalog);//4.提交事务TransactionUtil.commit(sqlSession);} catch (Exception e) {TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}}@Overridepublic Catalog findById(String id) {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//3.调用Dao层操作return catalogDao.findById(id);} catch (Exception e) {throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}}@Overridepublic List findAll() {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//3.调用Dao层操作return catalogDao.findAll();} catch (Exception e) {throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}}@Overridepublic PageInfo findAll(int page, int size) {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//3.调用Dao层操作PageHelper.startPage(page, size);List all = catalogDao.findAll();PageInfo pageInfo = new PageInfo(all);return pageInfo;} catch (Exception e) {throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}}
}

（6）创建servlet：com.itheima.web.controller.store.CatalogServlet

// uri:/store/catalog?operation=list
@WebServlet("/store/catalog")
public class CatalogServlet extends BaseServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}}private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//进入列表页//获取数据int page = 1;int size = 5;if(StringUtils.isNotBlank(request.getParameter("page"))){page = Integer.parseInt(request.getParameter("page"));}if(StringUtils.isNotBlank(request.getParameter("size"))){size = Integer.parseInt(request.getParameter("size"));}PageInfo all = catalogService.findAll(page, size);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/catalog/list.jsp").forward(request,response);}private void toAdd(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/catalog/add.jsp").forward(request,response);}private void save(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象Catalog catalog = BeanUtil.fillBean(request,Catalog.class,"yyyy-MM-dd");//调用业务层接口savecatalogService.save(catalog);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/catalog?operation=list");}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");Catalog catalog = catalogService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("catalog",catalog);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/catalog/update.jsp").forward(request,response);}private void edit(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象Catalog catalog = BeanUtil.fillBean(request,Catalog.class,"yyyy-MM-dd");//调用业务层接口savecatalogService.update(catalog);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/catalog?operation=list");}private void delete(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象Catalog catalog = BeanUtil.fillBean(request,Catalog.class);//调用业务层接口savecatalogService.delete(catalog);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/catalog?operation=list");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}
}

（7）修改BaseServlet，添加CatalogService

public class BaseServlet extends HttpServlet {protected CompanyService companyService;protected DeptService deptService;protected UserService userService;protected CourseService courseService;protected CatalogService catalogService;@Overridepublic void init() throws ServletException {companyService = new CompanyServiceImpl();deptService = new DeptServiceImpl();userService = new UserServiceImpl();courseService = new CourseServiceImpl();catalogService = new CatalogServiceImpl();}
}

（8）创建页面存放目录/WEB-INF/pages/store/catalog，然后从今日课程资料中找到模块页面\catalog下的所有页面到该目录

（9）修改servlet代码，找到toAdd方法，在去添加页面之前查询所有的学科数据

private void toAdd(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//加载学科信息List all = courseService.findAll();request.setAttribute("courseList",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/catalog/add.jsp").forward(request,response);
}

（10）保存目录的时候要保存创建时间，修改业务层的save方法，添加对创建时间的保存

@Override
public void save(Catalog catalog) {SqlSession sqlSession = null;try {//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoCatalogDao catalogDao = MapperFactory.getMapper(sqlSession, CatalogDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();catalog.setId(id);catalog.setCreateTime(new Date());//3.调用Dao层操作catalogDao.save(catalog);//4.提交事务TransactionUtil.commit(sqlSession);} catch (Exception e) {TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志} finally {try {TransactionUtil.close(sqlSession);} catch (Exception e) {e.printStackTrace();}}
}

（11）修改servlet代码，找到toEdit方法，去到编辑页面之前查询所有的学科信息，

private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");Catalog catalog = catalogService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("catalog",catalog);//加载学科信息List all = courseService.findAll();request.setAttribute("courseList",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/catalog/update.jsp").forward(request,response);
}

（12）启动项目，进行测试

4. 题目模块

4.1 题目模块快速开发

（1）创建题目实体：com.itheima.domain.store.Question

public class Question {private String id;			//题目IDprivate String companyId;	//所属企业private String catalogId;	//题目所属目录IDprivate String remark;		//题目简介private String subject;     //题干private String analysis;	//题目分析private String type;       	//题目类型  1:单选，2：多选，3：简答private String difficulty; 	//难易程度： 1极易 2容易 3普通  4困难  5极难private String isClassic; 	//是否经典面试题 0：否 1：是private String state;   	//题目状态  0：不可用  1：可用（只有审核通过的题目才可以设置）private String reviewStatus;//审核状态  -1 审核不通过  0 审核中   1 审核通过private Date createTime;private Company company;private Catalog catalog;// getter/setter 略
}

（2）创建dao接口：com.itheima.dao.store.QuestionDao

public interface QuestionDao {int save(Question question);int delete(Question question);int update(Question question);Question findById(String id);List findAll();
}

（3）添加题目dao的映射配置文件，之前已操作，略

（4）创建业务层接口：com.itheima.service.store.QuestionService

public interface QuestionService {/*** 添加* @param question* @return*/void save(Question question);/*** 删除* @param question* @return*/void delete(Question question);/*** 修改* @param question* @return*/void update(Question question);/*** 查询单个* @param id 查询的条件（id）* @return 查询的结果，单个对象*/Question findById(String id);/*** 查询全部的数据* @return 全部数据的列表对象*/List findAll();/*** 分页查询数据* @param page 页码* @param size 每页显示的数据总量* @return*/PageInfo findAll(int page, int size);
}

（5）创建业务层实现类：com.itheima.service.store.impl.QuestionServiceImpl

public class QuestionServiceImpl implements QuestionService {@Overridepublic void save(Question question) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();question.setId(id);//3.调用Dao层操作questionDao.save(question);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic void delete(Question question) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//3.调用Dao层操作questionDao.delete(question);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic void update(Question question) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//3.调用Dao层操作questionDao.update(question);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic Question findById(String id) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//3.调用Dao层操作return questionDao.findById(id);}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic List findAll() {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//3.调用Dao层操作return questionDao.findAll();}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic PageInfo findAll(int page, int size) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//3.调用Dao层操作PageHelper.startPage(page,size);List all = questionDao.findAll();PageInfo pageInfo = new PageInfo(all);return pageInfo;}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}
}

（6）创建servlet：com.itheima.web.controller.store.QuestionServlet

// uri:/store/question?operation=list
@WebServlet("/store/question")
public class QuestionServlet extends BaseServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}}private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//进入列表页//获取数据int page = 1;int size = 5;if(StringUtils.isNotBlank(request.getParameter("page"))){page = Integer.parseInt(request.getParameter("page"));}if(StringUtils.isNotBlank(request.getParameter("size"))){size = Integer.parseInt(request.getParameter("size"));}PageInfo all = questionService.findAll(page, size);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/question/list.jsp").forward(request,response);}private void toAdd(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/question/add.jsp").forward(request,response);}private void save(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(request,Question.class,"yyyy-MM-dd");//调用业务层接口savequestionService.save(question);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");Question question = questionService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("question",question);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/question/update.jsp").forward(request,response);}private void edit(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(request,Question.class,"yyyy-MM-dd");//调用业务层接口savequestionService.update(question);//跳转回到页面list//list(request,response);response.sendRedirect(request.getContextPath()+"/store/question?operation=list");}private void delete(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(request,Question.class);//调用业务层接口savequestionService.delete(question);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}
}

（7）修改BaserServlet，添加QuestionService

public class BaseServlet extends HttpServlet {protected CompanyService companyService;protected DeptService deptService;protected UserService userService;protected CourseService courseService;protected CatalogService catalogService;protected QuestionService questionService;@Overridepublic void init() throws ServletException {companyService = new CompanyServiceImpl();deptService = new DeptServiceImpl();userService = new UserServiceImpl();courseService = new CourseServiceImpl();catalogService = new CatalogServiceImpl();questionService = new QuestionServiceImpl();}
}

（8）创建页面存放目录,/WEB-INF/pages/store/question，从今日课程资料中找到模块页面\question，将下面的所有页面拷贝到该目录下

（9）修改servlet，找到toAdd方法，去添加页面之前查询企业和目录数据

private void toAdd(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {List companyList = companyService.findAll();List catalogList = catalogService.findAll();request.setAttribute("companyList",companyList);request.setAttribute("catalogList",catalogList);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/question/add.jsp").forward(request,response);
}

找到toEdit方法，去修改页面之前查询企业和目录数据

private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");Question question = questionService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("question",question);List companyList = companyService.findAll();List catalogList = catalogService.findAll();request.setAttribute("companyList",companyList);request.setAttribute("catalogList",catalogList);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/question/update.jsp").forward(request,response);
}

（10）修改业务层代码，找到添加数据的方法，需要新增审核状态和创建时间的数据

@Override
public void save(Question question) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();question.setId(id);//设置新创建的题目默认的审核状态为未审核（0）question.setReviewStatus("0");question.setCreateTime(new Date());//3.调用Dao层操作questionDao.save(question);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}
}

（11）修改查询所有数据时的排序，修改对应的dao映射配置文件QuestionDao.xml

selectfrom st_questionorder by create_time desc

（12）在进行数据修改时，有些数据是不能修改的，我们可以在持久层映射配置文件中进行控制

updatest_questionsetcompany_id = #{companyId,jdbcType=VARCHAR},catalog_id = #{catalogId,jdbcType=VARCHAR},remark = #{remark,jdbcType=VARCHAR},subject = #{subject,jdbcType=VARCHAR},analysis = #{analysis,jdbcType=VARCHAR},difficulty = #{difficulty,jdbcType=VARCHAR},is_classic = #{isClassic,jdbcType=VARCHAR},state = #{state,jdbcType=VARCHAR}whereid = #{id,jdbcType=VARCHAR}

4.2 文件上传基础演示

文件上传功能需要前台功能和后台功能共同配合完成

前台：文件上传的三要素

• 页面提供文件上传的表单元素

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-Lly18nl2-1645023275754)(./img/6.png)]

• form表单enctype属性的值为multipart/form-data

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-JgOgNp24-1645023275755)(./img/7.png)]

• 表单的提交方式必须是POST，get方式无法提交大量的数据

后台：可以使用的技术有很多，在此处我们使用apache提供的commons-fileupload组件完成文件上次操作，后台的操作步骤如下

• 确认请求操作是否支持文件上传
• 创建磁盘工厂对象，用于将页面上传的文件保存到磁盘中
• 获取servet文件上传核心对象
• 读取数据
• 对读取到数据中的文件表单进行操作，并将内容写到指定位置

下面我们开始进行文件上传的演示：

（1）从今日课程资料找到文件下载\testFileUpload.jsp文件上传页面，将其添加到项目/WEB-INF/pages/store/question目录下

（2）在question目录下的list.jsp页面上添加一个新的按钮，点击该按钮跳转到文件上传页面

 测试文件上传

（3）在QuestionServlet中添加toTestUpload方法，跳转到文件上传页面

@WebServlet("/store/question")
public class QuestionServlet extends BaseServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}else if("toTestUpload".equals(operation)){this.toTestUpload(request,response);}else if("testUpload".equals(operation)){try {this.testUpload(request,response);} catch (Exception e) {e.printStackTrace();}}}private void toTestUpload(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {request.getRequestDispatcher("/WEB-INF/pages/store/question/testFileUpload.jsp").forward(request,response);}private void testUpload(HttpServletRequest request,HttpServletResponse response) throws Exception {}
}   

（4）完成文件上传的后台代码

private void testUpload(HttpServletRequest request,HttpServletResponse response) throws Exception {//1.确认该操作是否支持文件上传操作，enctype="multipart/form-data"if(ServletFileUpload.isMultipartContent(request)){//2.创建磁盘工厂对象DiskFileItemFactory factory = new DiskFileItemFactory();//3.Servlet文件上传核心对象ServletFileUpload fileUpload = new ServletFileUpload(factory);//4.从request中读取数据List fileItems = fileUpload.parseRequest(request);for(FileItem item : fileItems){//5.当前表单是否是文件表单if(!item.isFormField()){//6.从临时存储文件的地方将内容写入到指定位置item.write(new File(this.getServletContext().getRealPath("upload"),item.getName()));}}}
}

需要在项目webapp目录下创建一个upload目录用于存储上传过来的文件

（5）启动测试

4.3 添加题目时加入文件上传

（1）在题目实体中添加图片的属性

public class Question {// 其他属性略private String picture;public String getPicture() {return picture;}public void setPicture(String picture) {this.picture = picture;}
}    

（2）在对应的dao映射配置文件中添加图片字段的配置，在resultMap，查询的sql片段，保存，更新几个位置添加映射配置即可，更新的时候是不需要更改图片的名称，因此是去掉对图片名称的更新

id, catalog_id, company_id, remark,subject,analysis,type, difficulty, is_classic,state, review_status, create_time, picture


insert into st_question(id, company_id, catalog_id, remark, subject, analysis, type,difficulty, is_classic, state, review_status, create_time ,picture )values (#{id,jdbcType=VARCHAR}, #{companyId,jdbcType=VARCHAR}, #{catalogId,jdbcType=VARCHAR},#{remark,jdbcType=VARCHAR}, #{subject,jdbcType=VARCHAR}, #{analysis,jdbcType=VARCHAR},#{type,jdbcType=VARCHAR}, #{difficulty,jdbcType=VARCHAR}, #{isClassic,jdbcType=VARCHAR},#{state,jdbcType=VARCHAR}, #{reviewStatus,jdbcType=VARCHAR}, #{createTime,jdbcType=TIMESTAMP},#{picture,jdbcType=VARCHAR} )


updatest_questionsetcompany_id = #{companyId,jdbcType=VARCHAR},catalog_id = #{catalogId,jdbcType=VARCHAR},remark = #{remark,jdbcType=VARCHAR},subject = #{subject,jdbcType=VARCHAR},analysis = #{analysis,jdbcType=VARCHAR},difficulty = #{difficulty,jdbcType=VARCHAR},is_classic = #{isClassic,jdbcType=VARCHAR},state = #{state,jdbcType=VARCHAR}whereid = #{id,jdbcType=VARCHAR}

（3）在question模块的添加页面add.jsp中加入图片上传的表单项

题干图片

（4）在servlet中修改保存题目的方法save，首先要更改的就是接收数据的方式，我们要按照文件上传的形式来接收

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){try {this.save(request, response);} catch (Exception e) {e.printStackTrace();}}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}else if("toTestUpload".equals(operation)){this.toTestUpload(request,response);}else if("testUpload".equals(operation)){try {this.testUpload(request,response);} catch (Exception e) {e.printStackTrace();}}
}private void save(HttpServletRequest request,HttpServletResponse response) throws Exception {//1.确认该操作是否支持文件上传操作，enctype="multipart/form-data"if(ServletFileUpload.isMultipartContent(request)){//2.创建磁盘工厂对象DiskFileItemFactory factory = new DiskFileItemFactory();//3.Servlet文件上传核心对象ServletFileUpload fileUpload = new ServletFileUpload(factory);//4.从request中读取数据List fileItems = fileUpload.parseRequest(request);// --处理form表单提交过来的普通数据//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(fileItems,Question.class);//调用业务层接口savequestionService.save(question);// --处理form表单提交过来的文件数据for(FileItem item : fileItems){//5.当前表单是否是文件表单if(!item.isFormField()){//6.从临时存储文件的地方将内容写入到指定位置item.write(new File(this.getServletContext().getRealPath("upload"),item.getName()));}}}//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");
}

4.4 文件上传的重名问题

（1）在question模块的list.jsp页面中添加对图片名称的展示

图片
企业
类别
题目
类型
难度
经典面试题
状态
审核结果
操作
${o.picture}
${o.company.name}
${o.catalog.name}
${o.subject}
单选多选简答
★
${o.isClassic eq "1" ? "经典题":"普通题"}
${o.state eq "1" ? "启用" : "禁用"}
审核通过审核中审核不通过
编辑审核

文件上传的常见问题：文件重名问题

（1）修改业务层接口QuestionService的保存方法，添加返回值，将图片的名称返回

/*** 添加* @param question* @return 保存的图片名称*/
String save(Question question);

（2）修改实现类，添加对图片名称的存储及返回图片的名称，图片名称使用该条数据的id

@Override
public String save(Question question) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();question.setId(id);//设置新创建的题目默认的审核状态为未审核（0）question.setReviewStatus("0");question.setCreateTime(new Date());//设置当前存储的图片名称为id值question.setPicture(id);//3.调用Dao层操作questionDao.save(question);//4.提交事务TransactionUtil.commit(sqlSession);return id;}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}
}

（3）在servlet中的save方法中接收图片名称

private void save(HttpServletRequest request,HttpServletResponse response) throws Exception {//1.确认该操作是否支持文件上传操作，enctype="multipart/form-data"if(ServletFileUpload.isMultipartContent(request)){//2.创建磁盘工厂对象DiskFileItemFactory factory = new DiskFileItemFactory();//3.Servlet文件上传核心对象ServletFileUpload fileUpload = new ServletFileUpload(factory);//4.从request中读取数据List fileItems = fileUpload.parseRequest(request);// --处理form表单提交过来的普通数据//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(fileItems,Question.class);//调用业务层接口saveString picture = questionService.save(question);// --处理form表单提交过来的文件数据for(FileItem item : fileItems){//5.当前表单是否是文件表单if(!item.isFormField()){//6.从临时存储文件的地方将内容写入到指定位置item.write(new File(this.getServletContext().getRealPath("upload"),picture));}}}//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");
}

4.5 修改题目时加入文件上传

修改之前需要先将图片展示出来

（1）在question模块的update.jsp页面中添加图片的展示，同时把修改时上传图片的表单项添加进去，以及表单也要配套修改

题干图片
题干图片

（2）修改后台的servlet，找到edit方法进行修改

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){try {this.save(request, response);} catch (Exception e) {e.printStackTrace();}}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){try {this.edit(request,response);} catch (Exception e) {e.printStackTrace();}}else if("delete".equals(operation)){this.delete(request,response);}else if("toTestUpload".equals(operation)){this.toTestUpload(request,response);}else if("testUpload".equals(operation)){try {this.testUpload(request,response);} catch (Exception e) {e.printStackTrace();}}
}
private void edit(HttpServletRequest request, HttpServletResponse response) throws Exception {//1.确认该操作是否支持文件上传操作，enctype="multipart/form-data"if(ServletFileUpload.isMultipartContent(request)){//2.创建磁盘工厂对象DiskFileItemFactory factory = new DiskFileItemFactory();//3.Servlet文件上传核心对象ServletFileUpload fileUpload = new ServletFileUpload(factory);//4.从request中读取数据List fileItems = fileUpload.parseRequest(request);// --处理form表单提交过来的普通数据//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(fileItems,Question.class);//调用业务层接口savequestionService.update(question);// --处理form表单提交过来的文件数据for(FileItem item : fileItems){//5.当前表单是否是文件表单if(!item.isFormField()){//6.从临时存储文件的地方将内容写入到指定位置item.write(new File(this.getServletContext().getRealPath("upload"),question.getId()));}}}//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");
}

（3）业务层实现类的update方法在进行数据修改时，图片名称不需要修改，这个我们在持久层的update操作时去掉对图片的更改，我们改一下对应的映射配置文件（这步操作之前已完成）如下

updatest_questionsetcompany_id = #{companyId,jdbcType=VARCHAR},catalog_id = #{catalogId,jdbcType=VARCHAR},remark = #{remark,jdbcType=VARCHAR},subject = #{subject,jdbcType=VARCHAR},analysis = #{analysis,jdbcType=VARCHAR},difficulty = #{difficulty,jdbcType=VARCHAR},is_classic = #{isClassic,jdbcType=VARCHAR},state = #{state,jdbcType=VARCHAR}whereid = #{id,jdbcType=VARCHAR}

4.6 兼容图片上传可选操作与显示问题

问题：

如果在新增的时候没有选择上传图片，会导致在修改的时候页面上展示不出图片，如下图所示

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-oAmvWnSk-1645023275756)(./img/8.png)]

产生问题的原因：

新增的时候虽然没有上传图片，但是由于我们保存数据的时候默认是将数据的id作为图片的名称，所以在展示的时候会去找这个名称的图片，但是我们又没上传因此会找到不到

改进方法：

在新增时做一个判断，如果上传了图片再去保存图片的名称，没有上传则不保存图片的名称

（1）在servlet的add方法中去判断当前是否上传文件，可以用一个布尔值标记来表明是否有文件上传，同时在业务层执行保存操作时可以把这个是否有图片的标记传递过去

private void save(HttpServletRequest request,HttpServletResponse response) throws Exception {//1.确认该操作是否支持文件上传操作，enctype="multipart/form-data"if(ServletFileUpload.isMultipartContent(request)){//2.创建磁盘工厂对象DiskFileItemFactory factory = new DiskFileItemFactory();//3.Servlet文件上传核心对象ServletFileUpload fileUpload = new ServletFileUpload(factory);//4.从request中读取数据List fileItems = fileUpload.parseRequest(request);//创建一个标记位,标记当前时候有上传文件的操作boolean flag = false;for(FileItem item :fileItems){if(StringUtils.isNotBlank(item.getName())){flag = true;break;}}// --处理form表单提交过来的普通数据//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(fileItems,Question.class);//调用业务层接口saveString picture = questionService.save(question , flag);// --处理form表单提交过来的文件数据for(FileItem item : fileItems){//5.当前表单是否是文件表单if(!item.isFormField()){//6.从临时存储文件的地方将内容写入到指定位置item.write(new File(this.getServletContext().getRealPath("upload"),picture));}}}//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");
}

（2）修改业务层接口方法save，添加参数

/*** 添加* @param question* @param flag 是否有上传文件的操作* @return 保存的图片名称*/
String save(Question question,boolean flag);

（3）修改对应的接口实现类：

@Override
public String save(Question question,boolean flag) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();question.setId(id);//设置新创建的题目默认的审核状态为未审核（0）question.setReviewStatus("0");question.setCreateTime(new Date());//检测到前端上传文件了，记录文件名，否则不记录if(flag) {//设置当前存储的图片名称为id值question.setPicture(id);}//3.调用Dao层操作questionDao.save(question);//4.提交事务TransactionUtil.commit(sqlSession);return id;}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}
}

（4）在修改时，如果没有图片则不显示图片，有图片信息的时候再显示，我们可以使用进行判断

题干图片

 0}">
题干图片

（5）页面修改完成后，在进行真正的修改操作时，我们同样需要进行判断，如果上传了图片则进行修改，否则不进行修改。

找到后台的servlet的edit方法，做出如下修改

private void edit(HttpServletRequest request, HttpServletResponse response) throws Exception {//1.确认该操作是否支持文件上传操作，enctype="multipart/form-data"if(ServletFileUpload.isMultipartContent(request)){//2.创建磁盘工厂对象DiskFileItemFactory factory = new DiskFileItemFactory();//3.Servlet文件上传核心对象ServletFileUpload fileUpload = new ServletFileUpload(factory);//4.从request中读取数据List fileItems = fileUpload.parseRequest(request);//创建一个标记位,标记当前时候有上传文件的操作boolean flag = false;for(FileItem item :fileItems){if(StringUtils.isNotBlank(item.getName())){flag = true;break;}}// --处理form表单提交过来的普通数据//将数据获取到，封装成一个对象Question question = BeanUtil.fillBean(fileItems,Question.class);//调用业务层接口savequestionService.update(question , flag);// --处理form表单提交过来的文件数据for(FileItem item : fileItems){//5.当前表单是否是文件表单if(!item.isFormField()){//6.从临时存储文件的地方将内容写入到指定位置item.write(new File(this.getServletContext().getRealPath("upload"),question.getId()));}}}//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/question?operation=list");
}

（6）同样需要修改业务层接口，在update方法上添加是否修改图片的参数

/*** 修改* @param question* @param flag 是否有上传文件的操作* @return*/
void update(Question question,boolean flag);

（7）在业务层实现类中修改该方法

@Override
public void update(Question question, boolean flag) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionDao questionDao = MapperFactory.getMapper(sqlSession,QuestionDao.class);//检测到前端上传文件了，记录文件名，否则不记录if(flag) {//设置当前存储的图片名称为id值question.setPicture(question.getId());}//3.调用Dao层操作questionDao.update(question);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}
}

（8）在持久层dao真正进行update操作的时候我们把对图片的更新添加进去，我们去修改对应的映射配置文件即可

updatest_questionsetcompany_id = #{companyId,jdbcType=VARCHAR},catalog_id = #{catalogId,jdbcType=VARCHAR},remark = #{remark,jdbcType=VARCHAR},subject = #{subject,jdbcType=VARCHAR},analysis = #{analysis,jdbcType=VARCHAR},difficulty = #{difficulty,jdbcType=VARCHAR},is_classic = #{isClassic,jdbcType=VARCHAR},picture = #{picture,jdbcType=VARCHAR},state = #{state,jdbcType=VARCHAR}whereid = #{id,jdbcType=VARCHAR}

5. 题目选项模块

5.1 列表页制作

（1）创建题目选项实体：com.itheima.domain.store.QuestionItem

public class QuestionItem {private String id;          	//IDprivate String questionId;  //题目IDprivate String content;     //选项内容private String picture;      //选项图片private String isRight;    //是否正确答案@Overridepublic String toString() {return "QuestionItem{" +"id='" + id + '\'' +", questionId='" + questionId + '\'' +", content='" + content + '\'' +", picture='" + picture + '\'' +", isRight='" + isRight + '\'' +'}';}// getter/setter方法略
}

（2）创建dao接口：com.itheima.dao.store.QuestionItemDao

public interface QuestionItemDao {int save(QuestionItem questionItem);int delete(QuestionItem questionItem);int update(QuestionItem questionItem);QuestionItem findById(String id);List findAll();
}

（3）添加对应的映射配置文件，之前已导入过了

（4）创建业务层接口：com.itheima.service.store.QuestionItemService

public interface QuestionItemService {/*** 添加* @param questionItem* @return*/void save(QuestionItem questionItem);/*** 删除* @param questionItem* @return*/void delete(QuestionItem questionItem);/*** 修改* @param questionItem* @return*/void update(QuestionItem questionItem);/*** 查询单个* @param id 查询的条件（id）* @return 查询的结果，单个对象*/QuestionItem findById(String id);/*** 查询全部的数据* @return 全部数据的列表对象*/List findAll();/*** 分页查询数据* @param page 页码* @param size 每页显示的数据总量* @return*/PageInfo findAll(int page, int size);
}

（5）创建业务层实现类：com.itheima.service.store.impl.QuestionItemServiceImpl

我们基于CompanyServiceImpl拷贝然后改造

public class QuestionItemServiceImpl implements QuestionItemService {@Overridepublic void save(QuestionItem questionItem) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//id使用UUID的生成策略来获取String id = UUID.randomUUID().toString();questionItem.setId(id);//3.调用Dao层操作questionItemDao.save(questionItem);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic void delete(QuestionItem questionItem) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//3.调用Dao层操作questionItemDao.delete(questionItem);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic void update(QuestionItem questionItem) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//3.调用Dao层操作questionItemDao.update(questionItem);//4.提交事务TransactionUtil.commit(sqlSession);}catch (Exception e){TransactionUtil.rollback(sqlSession);throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic QuestionItem findById(String id) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//3.调用Dao层操作return questionItemDao.findById(id);}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic List findAll() {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//3.调用Dao层操作return questionItemDao.findAll();}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}@Overridepublic PageInfo findAll(int page, int size) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//3.调用Dao层操作PageHelper.startPage(page,size);List all = questionItemDao.findAll();PageInfo pageInfo = new PageInfo(all);return pageInfo;}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}}
}

（6）创建servlet：com.itheima.web.controller.store.QuestionItemServlet

基于CompanyServlet拷贝进行改造（修改完成后有些方法其实没有用，我们暂时不用去修改，后续我们会逐级进行修改）

@WebServlet("/store/questionItem")
public class QuestionItemServlet extends BaseServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("toAdd".equals(operation)){this.toAdd(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}}private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//进入列表页//获取数据int page = 1;int size = 5;if(StringUtils.isNotBlank(request.getParameter("page"))){page = Integer.parseInt(request.getParameter("page"));}if(StringUtils.isNotBlank(request.getParameter("size"))){size = Integer.parseInt(request.getParameter("size"));}PageInfo all = questionItemService.findAll(page, size);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/list.jsp").forward(request,response);}private void toAdd(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/add.jsp").forward(request,response);}private void save(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class,"yyyy-MM-dd");//调用业务层接口savequestionItemService.save(questionItem);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/questionItem?operation=list");}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");QuestionItem questionItem = questionItemService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("questionItem",questionItem);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/update.jsp").forward(request,response);}private void edit(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class,"yyyy-MM-dd");//调用业务层接口savequestionItemService.update(questionItem);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/questionItem?operation=list");}private void delete(HttpServletRequest request, HttpServletResponse response) throws IOException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class);//调用业务层接口savequestionItemService.delete(questionItem);//跳转回到页面listresponse.sendRedirect(request.getContextPath()+"/store/questionItem?operation=list");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}

（7）在BaseServlet中添加QuestionItemService

public class BaseServlet extends HttpServlet {protected CompanyService companyService;protected DeptService deptService;protected UserService userService;protected CourseService courseService;protected CatalogService catalogService;protected QuestionService questionService;protected QuestionItemService questionItemService;@Overridepublic void init() throws ServletException {companyService = new CompanyServiceImpl();deptService = new DeptServiceImpl();userService = new UserServiceImpl();courseService = new CourseServiceImpl();catalogService = new CatalogServiceImpl();questionService = new QuestionServiceImpl();questionItemService = new QuestionItemServiceImpl();}
}

（8）创建页面存放的目录/WEB-INF/pages/store/questionItem，从今日课程资料中的模块页面\questionItem下复制所有的页面到刚创建好的目录中

（9）在question模块的list.jsp页面中添加题目选项列表页的入口，因为题目选项是针对某个具体的题目的，在每条列表数据的操作中添加一个配置选项的按钮

配置选项

同时在questionItem模块中的list.jsp页面中我们需要删除一些页面元素，分页，新建按钮，删除按钮，只留下刷新按钮

（10）在后台servlet的list方法中接收题目的id，我们要查询的列表应该是该题目下的所有选项列表

private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String questionId = request.getParameter("questionId");PageInfo all = questionItemService.findAll(questionId,1, 100);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/list.jsp").forward(request,response);
}

（11）修改业务层接口方法，添加参数，注意是改带分页的那个方法

/*** 分页查询数据* @param questionId 题目对应的id* @param page 页码* @param size 每页显示的数据总量* @return*/
PageInfo findAll(String questionId,int page, int size);

（12）在业务层实现类中修改对应的方法

@Override
public PageInfo findAll(String questionId,int page, int size) {SqlSession sqlSession = null;try{//1.获取SqlSessionsqlSession = MapperFactory.getSqlSession();//2.获取DaoQuestionItemDao questionItemDao = MapperFactory.getMapper(sqlSession,QuestionItemDao.class);//3.调用Dao层操作PageHelper.startPage(page,size);List all = questionItemDao.findAll(questionId);PageInfo pageInfo = new PageInfo(all);return pageInfo;}catch (Exception e){throw new RuntimeException(e);//记录日志}finally {try {TransactionUtil.close(sqlSession);}catch (Exception e){e.printStackTrace();}}
}

（13）修改持久层接口方法findAll，添加查询参数

/*** 根据题目id查询所有选项 * @param questionId* @return*/
List findAll(String questionId);

（14）修改dao映射配置文件，添加条件

selectfrom st_question_itemwhere question_id = #{questionId,jdbcType=VARCHAR}

（15）对于业务层原有的不带任何参数的findAll方法，我们可以去掉，删除接口和实现类中的无参的findAll方法

（16）启动项目测试效果

5.2 添加功能制作

（1）在后台servlet的doGet方法中去掉一些逻辑，toAdd的逻辑判断和对应的toAdd方法需要删除，然后直接查看save方法

（2）save方法最后需要去跳转页面，我们让它直接调用list方法，该方法最后就是跳转页面的

private void save(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class,"yyyy-MM-dd");//调用业务层接口savequestionItemService.save(questionItem);//跳转回到页面listlist(request,response);
}

（3）找到questionItem模块下的list.jsp页面，在

private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String questionId = request.getParameter("questionId");//进入list页时添加对应的问题id，为添加操作使用request.setAttribute("questionId",questionId);PageInfo all = questionItemService.findAll(questionId,1, 100);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/list.jsp").forward(request,response);
}

private void delete(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class);//调用业务层接口savequestionItemService.delete(questionItem);//跳转回到页面listlist(request,response);
}

private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");QuestionItem questionItem = questionItemService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("questionItem",questionItem);//跳转回到页面listlist(request,response);
}

编辑

选项内容
选项图片
<%--
是否正确答案
请选择正确答案错误选项
--%>
是否正确答案
请选择正确答案错误选项

（4）启动后测试，发现了新的问题，我们要提交编辑的数据，但结果却变成了保存，问题的原因是什么呢？

经过分析发现是因为表单的提交路径一直写的就是保存的路径，如何解决呢？

通过后台传递一个操作类型的变量值到前端，前端在表单的action里面使用该变量值，通过这个变量我们来控制是新增还是编辑

在后台的list和toEdit方法中来操作该变量值

private void list2(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String questionId = request.getParameter("questionId");//进入list页时添加对应的问题id，为添加操作使用request.setAttribute("questionId",questionId);//获取数据PageInfo all = questionItemService.findAll(questionId, 1, 100);//将数据保存到指定的位置request.setAttribute("page",all);if(request.getAttribute("operation") == null) {//保存一个操作的类型，传递到前端saverequest.setAttribute("operation", "save");}//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/list.jsp").forward(request,response);
}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");QuestionItem questionItem = questionItemService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("questionItem",questionItem);//保存一个操作的类型，传递到前端saverequest.setAttribute("operation","edit");//跳转回到页面listlist(request,response);
}

然后需要在页面的表单action属性上接收该值

（5）启动项目进行测试

（6）测试发现编辑后，提交编辑的数据完成编辑哦呼跳转回页面，页面所有的数据又消失了，回到后台servlet查看edit方法，发现是页面跳转的问题

private void edit(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class,"yyyy-MM-dd");//调用业务层接口savequestionItemService.update(questionItem);//跳转回到页面listlist(request,response);
}

（7）数据显示的问题解决后我们发现数据并没有真正的修改完成，分析原因发现是因为编辑后提交编辑的数据进行修改，但是没有提交问题选项的id值，我们需要在表单中接收问题选项的id值，能够让它在编辑的时候被提交到后台

（8）启动项目进行测试

5.5 添加修改功能合并

（1）把questionItem/list.jsp进行备份，questionItem/list2.jsp

（2）将后台list,toEdit方法进行备份，分别叫做list2,toEdit2，与前台的list2.jsp配套，

（3）在后台servlet中封装一个saveOrUpdate方法，同时需要修改doGet方法

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}else if("saveOrUpdate".equals(operation)){this.saveOrUpdate(request,response);}
}private void saveOrUpdate(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class,"yyyy-MM-dd");//如果页面传递了当前数据的id，则为修改业务，否则为添加业务if(StringUtils.isNotBlank(questionItem.getId())){questionItemService.update(questionItem);}else {questionItemService.save(questionItem);}//跳转回到页面listlist(request,response);
}

（4）修改原始的list,toEdit方法，不需要之前添加操作标识的变量了

private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String questionId = request.getParameter("questionId");//进入list页时添加对应的问题id，为添加操作使用request.setAttribute("questionId",questionId);//获取数据PageInfo all = questionItemService.findAll(questionId, 1, 100);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/list.jsp").forward(request,response);
}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");QuestionItem questionItem = questionItemService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("questionItem",questionItem);//跳转回到页面listlist(request,response);
}

（5）修改list.jsp页面表单的action属性

（6）启动项目测试

5.6 删除功能相关问题及解决方案

题目选项功能完成后，伴随而来的是题目的有些功能出现了问题，比如：删除题目，题目数据删除了，那该题目下的选项数据呢？目前是没有删除，

因此我们要解决的是：删除题目数据的时候伴随着删除该题目下的选项数据

解决方案

解决方案一:触发器

◆注意使用触发器实现是将业务绑定到了数据库端,在进行系统设计时要确认方案

解决方案二:业务层删除操作中分别调用两个模块的删除功能

◆注意删除主使用按id删除,删除从使用按关联id删除

◆注意删除的顺序,先删从,后删主

解决方案三:存储过程

◆整套的数据层解决方案,没有单一功能使用的

解决方案四:依赖框架提供的级联删除功能

动项目进行测试

5.5 添加修改功能合并

（1）把questionItem/list.jsp进行备份，questionItem/list2.jsp

（2）将后台list,toEdit方法进行备份，分别叫做list2,toEdit2，与前台的list2.jsp配套，

（3）在后台servlet中封装一个saveOrUpdate方法，同时需要修改doGet方法

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String operation = request.getParameter("operation");if("list".equals(operation)){this.list(request,response);}else if("save".equals(operation)){this.save(request, response);}else if("toEdit".equals(operation)){this.toEdit(request,response);}else if("edit".equals(operation)){this.edit(request,response);}else if("delete".equals(operation)){this.delete(request,response);}else if("saveOrUpdate".equals(operation)){this.saveOrUpdate(request,response);}
}private void saveOrUpdate(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {//将数据获取到，封装成一个对象QuestionItem questionItem = BeanUtil.fillBean(request,QuestionItem.class,"yyyy-MM-dd");//如果页面传递了当前数据的id，则为修改业务，否则为添加业务if(StringUtils.isNotBlank(questionItem.getId())){questionItemService.update(questionItem);}else {questionItemService.save(questionItem);}//跳转回到页面listlist(request,response);
}

（4）修改原始的list,toEdit方法，不需要之前添加操作标识的变量了

private void list(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String questionId = request.getParameter("questionId");//进入list页时添加对应的问题id，为添加操作使用request.setAttribute("questionId",questionId);//获取数据PageInfo all = questionItemService.findAll(questionId, 1, 100);//将数据保存到指定的位置request.setAttribute("page",all);//跳转页面request.getRequestDispatcher("/WEB-INF/pages/store/questionItem/list.jsp").forward(request,response);
}private void toEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//查询要修改的数据findByIdString id = request.getParameter("id");QuestionItem questionItem = questionItemService.findById(id);//将数据加载到指定区域，供页面获取request.setAttribute("questionItem",questionItem);//跳转回到页面listlist(request,response);
}

（5）修改list.jsp页面表单的action属性

（6）启动项目测试

5.6 删除功能相关问题及解决方案

题目选项功能完成后，伴随而来的是题目的有些功能出现了问题，比如：删除题目，题目数据删除了，那该题目下的选项数据呢？目前是没有删除，

因此我们要解决的是：删除题目数据的时候伴随着删除该题目下的选项数据

解决方案

解决方案一:触发器

◆注意使用触发器实现是将业务绑定到了数据库端,在进行系统设计时要确认方案

解决方案二:业务层删除操作中分别调用两个模块的删除功能

◆注意删除主使用按id删除,删除从使用按关联id删除

◆注意删除的顺序,先删从,后删主

解决方案三:存储过程

◆整套的数据层解决方案,没有单一功能使用的

解决方案四:依赖框架提供的级联删除功能

解决方案五:定时维护/垃圾数据清理