Request&Response案例

2024-03-23 1074阅读

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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

            Request&Response案例

            1、环境准备

            Request&Response案例

            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

            Request&Response案例

            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:

            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

            Request&Response案例

            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
                
                    
                    
            
                            		
            
            密码

            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);
    }
}
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