文章目录

• 一、用户登录
• • 1、环境准备
  • • 数据库准备
    • 导入MyBatis坐标，MySQL驱动坐标
    • mybatis-config.xml准备
    • UserMapper.xml
    • 2、流程说明
    • • UserMapper接口
      • https://blog.csdn.net/rch041126/article/details/login.html
      • LoginServlet
      • 二、用户注册
      • • https://blog.csdn.net/rch041126/article/details/register.html
        • RegisterServlet

          一、用户登录

          

          1、环境准备

          

          数据库准备

          create database db1;
          -- 创建用户表
          CREATE TABLE tb_user(
                                  id int primary key auto_increment,
                                  username varchar(20) unique,
                                  password varchar(32)
          );
          -- 添加数据
          INSERT INTO tb_user(username,password) values('zhangsan','123'),('lisi','234');
          SELECT * FROM tb_user;
          

          导入MyBatis坐标，MySQL驱动坐标

                  
                      org.mybatis
                      mybatis
                      3.5.5
                  
                  
                      mysql
                      mysql-connector-java
                      5.1.34
                  
          

          mybatis-config.xml准备

          UserMapper.xml

          2、流程说明

          

          UserMapper接口

          package com.itheima.mapper;
          import com.itheima.pojo.User;
          import org.apache.ibatis.annotations.Insert;
          import org.apache.ibatis.annotations.Param;
          import org.apache.ibatis.annotations.Select;
          public interface UserMapper {
              /**
               * 根据用户名和密码查询用户对象
               * @param username
               * @param password
               * @return
               */
              @Select("select * from tb_user where username = #{username} and password = #{password}")
              User select(@Param("username") String username,@Param("password")  String password);
              /**
               * 根据用户名查询用户对象
               * @param username
               * @return
               */
              @Select("select * from tb_user where username = #{username}")
              User selectByUsername(String username);
              /**
               * 添加用户
               * @param user
               */
              @Insert("insert into tb_user values(null,#{username},#{password})")
              void add(User user);
          }
          

          https://blog.csdn.net/rch041126/article/details/login.html

          
          
              
              login
              
          
          
          
              
                  
          LOGIN IN
                  
          Username:
                  
          Password:
                  
          
                      
                         
                      没有账号？点击注册
                  
              
          
          
          
          

          LoginServlet

          package com.itheima.web;
          import com.itheima.mapper.UserMapper;
          import com.itheima.pojo.User;
          import com.itheima.util.SqlSessionFactoryUtils;
          import org.apache.ibatis.io.Resources;
          import org.apache.ibatis.session.SqlSession;
          import org.apache.ibatis.session.SqlSessionFactory;
          import org.apache.ibatis.session.SqlSessionFactoryBuilder;
          import javax.servlet.*;
          import javax.servlet.http.*;
          import javax.servlet.annotation.*;
          import java.io.IOException;
          import java.io.InputStream;
          import java.io.PrintWriter;
          @WebServlet("/loginServlet")
          public class LoginServlet extends HttpServlet {
              @Override
              protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
                  //1. 接收用户名和密码
                  String username = request.getParameter("username");
                  String password = request.getParameter("password");
                  //2. 调用MyBatis完成查询
                  //2.1 获取SqlSessionFactory对象
                 /* String resource = "mybatis-config.xml";
                  InputStream inputStream = Resources.getResourceAsStream(resource);
                  SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);*/
                  SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
                  //2.2 获取SqlSession对象
                  SqlSession sqlSession = sqlSessionFactory.openSession();
                  //2.3 获取Mapper
                  UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
                  //2.4 调用方法
                  User user = userMapper.select(username, password);
                  //2.5 释放资源
                  sqlSession.close();
                  //获取字符输出流，并设置content type
                  response.setContentType("text/html;charset=utf-8");
                  PrintWriter writer = response.getWriter();
                  //3. 判断user释放为null
                  if(user != null){
                      // 登陆成功
                      writer.write("登陆成功");
                  }else {
                      // 登陆失败
                      writer.write("登陆失败");
                  }
              }
              @Override
              protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
                  this.doGet(request, response);
              }
          }
          

          二、用户注册

          

          https://blog.csdn.net/rch041126/article/details/register.html

          
          
              
              欢迎注册
              
          
          
          
              
          
                  
          欢迎注册
                  已有帐号？ 登录
              
              
                  
          用户名
                          
          
                              
                              
          用户名不太受欢迎
                          
                      
          密码
                          
          
                              
                              
          密码格式有误
                          
                      
          
                      
                  
                  
          
          
          
          

          RegisterServlet

          package com.itheima.web;
          import com.itheima.mapper.UserMapper;
          import com.itheima.pojo.User;
          import com.itheima.util.SqlSessionFactoryUtils;
          import org.apache.ibatis.io.Resources;
          import org.apache.ibatis.session.SqlSession;
          import org.apache.ibatis.session.SqlSessionFactory;
          import org.apache.ibatis.session.SqlSessionFactoryBuilder;
          import javax.servlet.*;
          import javax.servlet.http.*;
          import javax.servlet.annotation.*;
          import java.io.IOException;
          import java.io.InputStream;
          @WebServlet("/registerServlet")
          public class RegisterServlet extends HttpServlet {
              @Override
              protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
                  //1. 接收用户数据
                  String username = request.getParameter("username");
                  String password = request.getParameter("password");
                  //封装用户对象
                  User user = new User();
                  user.setUsername(username);
                  user.setPassword(password);
                  //2. 调用mapper 根据用户名查询用户对象
                  //2.1 获取SqlSessionFactory对象
                 /* String resource = "mybatis-config.xml";
                  InputStream inputStream = Resources.getResourceAsStream(resource);
                  SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);*/
                  SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
                  //2.2 获取SqlSession对象
                  SqlSession sqlSession = sqlSessionFactory.openSession();
                  //2.3 获取Mapper
                  UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
                  //2.4 调用方法
                  User u = userMapper.selectByUsername(username);
                  //3. 判断用户对象释放为null
                  if( u == null){
                      // 用户名不存在，添加用户
                      userMapper.add(user);
                      // 提交事务
                      sqlSession.commit();
                      // 释放资源
                      sqlSession.close();
                  }else {
                      // 用户名存在，给出提示信息
                      response.setContentType("text/html;charset=utf-8");
                      response.getWriter().write("用户名已存在");
                  }
              }
              @Override
              protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
                  this.doGet(request, response);
              }
          }