Mybatis整合Servlet项目

总目录 (最下面 Mybatis分页扩展内容)

1. 如下图所式文件夹需要在Mybatis逆向工程中生成,有时间再说说Mybatis逆向工程

2. 什么是 Open Session In View

2.1 Open Session In View 模式：
Open Session In View 是将一个数据库会话对象绑定到当前请求线程中，在请求期间一直
保持数据库会话对象处于 Open 状态，使数据库会话对象在请求的整个期间都可以使用。直
到产生响应后关闭当前的数据库会话对象。

2.2 创建 OpenSqlSessionInViewFilter

package com.tong.web.filter;

import com.tong.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;

/***
 * 在filter中打开一个SqlSession
 */
@WebFilter("/*")
public class OpenSqlSessionInViewFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        try
        {
            filterChain.doFilter(servletRequest, servletResponse);
            sqlSession.commit();
        }catch (Exception e)
        {
            e.printStackTrace();
            sqlSession.rollback();
        }finally{
            MybatisUtils.closeSqlSession();
        }
    }

    @Override
    public void destroy() {

    }
}

3. 完成业务操作

3.1添加用户
3.1.1 修改 index.jsp

<%--
  Created by IntelliJ IDEA.
  User: 童蕴锐
  Date: 2021/7/29
  Time: 20:28
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>首页</title>
  </head>
  <body>
     <a href="addUsers.jsp">添加用户</a>
  </body>
</html>

3.1.2 创建 addUsers.jsp

<%--
  Created by IntelliJ IDEA.
  User: 童蕴锐
  Date: 2021/8/1
  Time: 19:50
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>添加用户</title>
</head>
<body>
    <form action="usersServlet.do" method="post">
        <input type="hidden" name="flag" value="addUsers"/>
        用户姓名:  <input type="text" name="username"/><br/>
        用户性别: <input type="text" name="userage"/><br>
        <input type="submit" value="OK"/>
    </form>
</body>
</html>

3.1.3 创建 UsersServlet

package com.tong.web.servlet;

import com.tong.pojo.Users;
import com.tong.service.UsersService;
import com.tong.service.impl.UsersServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/usersServlet.do")
public class UsersServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String flag = req.getParameter("flag");
        if("addUsers".equals(flag)){
            this.addUsers(req,resp);
        }
    }
    /**
     * 处理添加用户请求
     */
    private void addUsers(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
        Users users = this.createUsers(req);
        UsersService usersService = new UsersServiceImpl();
        usersService.addUsers(users);
        resp.sendRedirect("ok.jsp");
    }
    /**
     * 获取提交数据
     */
    private Users createUsers(HttpServletRequest req){
        String username = req.getParameter("username");
        String userage = req.getParameter("userage");
        Users users = new Users();
        users.setUsername(username);
        users.setUserage(Integer.valueOf(userage));
        return users;
    }

}

3.1.4 创建业务层

package com.tong.service;

import com.tong.pojo.Users;

/**
 * @author 童蕴锐
 */
public interface UsersService {

    void addUsers(Users users);
}

package com.tong.service.impl;

import com.tong.mapper.UsersMapper;
import com.tong.pojo.Users;
import com.tong.utils.MybatisUtils;
import com.tong.service.UsersService;
import org.apache.ibatis.session.SqlSession;

public class UsersServiceImpl implements UsersService {

    /***
     * 添加用户
     * @param users
     */
    @Override
    public void addUsers(Users users) {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UsersMapper usersMapper = sqlSession.getMapper(UsersMapper.class);
        usersMapper.insertSelective(users);
    }
}

3.1.5 创建成功页面

<%--
  Created by IntelliJ IDEA.
  User: 童蕴锐
  Date: 2021/8/1
  Time: 20:36
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
     操作成功！！！
</body>
</html>

3.2查询用户
3.2.1 修改 index.jsp

<%--
  Created by IntelliJ IDEA.
  User: 童蕴锐
  Date: 2021/8/1
  Time: 20:40
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
   <head>
        <title>$Title$</title>
   </head>
<body>
<a href="addUsers.jsp">添加用户</a> &nbsp; &nbsp;&nbsp;<a href="findUsers.jsp">查询用户</a>
  </body>
</html>

3.2.2 创建 findUsers.jsp

<%--
  Created by IntelliJ IDEA.
  User: 童蕴锐
  Date: 2021/8/1
  Time: 20:45
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>查询用户</title>
</head>
<body>
<form action="usersServlet.do" method="post">
<input type="hidden" name="flag" value="findUsers"/>
用户姓名： <input type="text" name="username"/><br/>
用户性别：<input type="text" name="usersex"/><br/>
<input type="submit" value="OK"/>
</form>
</body>
</html>

3.2.3 修改 UsersServlet

@WebServlet("/usersServlet.do")
public class UsersServlet extends HttpServlet {
        @Override

  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws 
  ServletException, IOException {

                  this.doPost(req, resp);
}
        @Override

 protected void doPost(HttpServletRequest req,HttpServletResponse resp) throws 
 ServletException, IOException {
                 String flag = req.getParameter("flag");

                 if("addUsers".equals(flag)){

                 this.addUsers(req,resp);

                  }else if("findUsers".equals(flag)){

                    this.findUsers(req,resp);

                  }
}

               /**
                 * 处理添加用户请求
               */

   private void addUsers(HttpServletRequest req, HttpServletResponse resp) throws 
   ServletException, IOException{

               Users users = this.createUsers(req);

               UsersService usersService = new UsersServiceImpl();

               usersService.addUsers(users);

               resp.sendRedirect("ok.jsp");
}

              /**
                * 获取提交数据
              */

   private Users createUsers(HttpServletRequest req){

             String username = req.getParameter("username");

             String usersex = req.getParameter("usersex");

             Users users = new Users();

             users.setUsername(username);

             users.setUsersex(usersex);

             return users;
}

             /**
               * 查询用户
             */

private void findUsers(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{

                Users users = this.createUsers(req);

                String pageIndex = req.getParameter("pageIndex");

                int page = 1;

                if(pageIndex != null && pageIndex.length() > 0){

                page = Integer.parseInt(pageIndex);

                }

              UsersService usersService = new UsersServiceImpl();

              PageInfo<Users> pageInfo = usersService.findUsers(page,users);

              req.setAttribute("pageInfo",pageInfo);

              req.setAttribute("users",users);

              req.getRequestDispatcher("showUsers.jsp").forward(req,resp);
          }
}

3.2.4 修改业务层

PageInfo<Users> findUsers(int page,Users users);

             /**
               * 查询用户
               *
             */

       @Override

    public PageInfo<Users> findUsers(int page, Users users) {

           SqlSession sqlSession = MybatisUtils.getSqlSession();

           UsersMapper usersMapper = sqlSession.getMapper(UsersMapper.class);

           UsersExample usersExample = this.createUsersExample(users);

           PageHelper.startPage(page,2);

           List<Users> list = usersMapper.selectByExample(usersExample);

           PageInfo<Users> pageInfo = new PageInfo<>(list);

           return pageInfo;
}

             /**
               * 生成查询条件
              */
       private UsersExample createUsersExample(Users users){

             UsersExample usersExample = new UsersExample();

             UsersExample.Criteria criteria = usersExample.createCriteria();

            if(users.getUsername() != null && users.getUsername().length() >0){

                     criteria.andUsernameEqualTo(users.getUsername());

                }

            if(users.getUsersex() != null && users.getUsersex().length() > 0){

                    criteria.andUsersexEqualTo(users.getUsersex());

                }
                     return usersExample;
}

扩展分页

3.3.2 添加 taglib 指令标签

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

3.3.3 创显示查询结果页面

<%--
  Created by IntelliJ IDEA.
  User: 童蕴锐
  Date: 2021/8/2
  Time: 20:45
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
   <head>
          <title>显示查询结果</title>
    <script>
       function subForm(pageIndex){
               document.getElementById("pageIndex").value=pageIndex;
               document.forms[0].submit();
}
    </script>
  </head>
<body>
         <form action="usersServlet.do" method="post">
              <input type="hidden" name="flag" value="findUsers"/>
              <input type="hidden" name="pageIndex" id="pageIndex"/>
              <input type="hidden" name="username" value="${users.username}"/>
              <input type="hidden" name="usersex" value="${users.usersex}"/>
         </form>

<table align="center" border="1" width="40%">
        <tr>
           <th>用户 ID</th>
           <th>用户姓名</th>
           <th>用户性别</th>
        </tr>
   <c:forEach items="${pageInfo.list}" var="users">
       <tr>
          <td>${users.userid}</td>
          <td>${users.username}</td>
          <td>${users.usersex}</td>
      </tr>
   </c:forEach>
<tr>
    <td colspan="3" align="center">
    <c:if test="${pageInfo.pageNum > 1}">
       <a href="#" onclick="subForm(${pageInfo.pageNum - 1})">上一页</a>
    </c:if>
    <c:forEach begin="1" end="${pageInfo.pages}" varStatus="st">
   <c:choose>
        <c:when test="${pageInfo.pageNum eq st.count}">
          <a style="color: red" href="#" onclick="subForm(${st.count})">${st.count}</a>
        </c:when>
   <c:otherwise>
         <a href="#" onclick="subForm(${st.count})">${st.count}</a>
   </c:otherwise>
  </c:choose>
 </c:forEach>
<c:if test="${pageInfo.pageNum < pageInfo.pages}">
<a href="#" onclick="subForm(${pageInfo.pageNum + 1})">下一页</a>
            </c:if>

         </td>

      </tr>

   </table>

  </body>

</html>

Mybatis整合Servlet项目

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