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JavaWeb——Requst&Response案例（用户登录、注册）

code • 2022-5-14 • java • 阅读 17

JavaWeb——Requst&Response案例（用户登录、注册）,第1张

1.环境准备 1.1准备静态页面到项目的webapp目录下
1.2创建db1数据库，创建tb_ user表，创建User实体类 

-- 创建数据库
create database db1;

use 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;

public class User {

    private Integer id;
    private String username;
    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

1.3导坐标 


    4.0.0

    com.myproject
    request_response
    1.0-SNAPSHOT
    war

    
        
        
            mysql
            mysql-connector-java
            8.0.21
        

        
        
            org.mybatis
            mybatis
            3.4.6
        

        
        
            javax.servlet
            javax.servlet-api
            3.1.0
            provided
        

        
        
            org.apache.maven
            maven-plugin-api
            2.0
        

        
        
            commons-io
            commons-io
            2.6
        
    

    
        
            
                org.apache.tomcat.maven
                tomcat7-maven-plugin
                2.2

1.4创建mybatis-config.xml核心配置文件

1.5 UserMapper.xml映射文件, UserMapper接口 
package com.mapper;

import com.pojo.User;
import org.apache.ibatis.annotations.Param;

public interface UserMapper {
    User select(@Param("username")String username,@Param("password") String password);
}

 

2.代码实现 

public interface UserMapper {
    User select(@Param("username")String username,@Param("password") String password);

    User selectByUsername(String username);

    void add(User user);

}





    
    
    
        INSERT INTO tb_user VALUES (null,#{username},#{password})
2.1用户登录 


@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受用户名和密码
        String username1 = request.getParameter("username");
        String password1 = request.getParameter("password");

        //2.调用Mybatis完成查询
        //2.1获取SqlSessionFactory对象：从官网复制
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.2获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //2.3获取mapper对象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        //2.4调用方法
        User select = mapper.select(username1, password1);
        //2.5释放资源
        sqlSession.close();

        //解析html，并解决中文乱码
        response.setContentType("text/html;charset=utf-8");
        //获取字符流
        PrintWriter writer = response.getWriter();

        //3.判断
        if (select != null) {
            writer.write("登录成功");
        } else {
            writer.write("登录失败");
        }
    }
}
2.2用户注册

 


@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受用户名和密码
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        //2.封装用户对象
        User user = new User();
        user.setUsername(username);
        user.setPassword(password);

        //3..调用Mybatis完成查询
        //3.1获取SqlSessionFactory对象：从官网复制
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //3.2获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.3获取mapper对象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        //3.4调用方法
        User select = mapper.selectByUsername(username);

        //解析html，并解决中文乱码
        response.setContentType("text/html;charset=utf-8");
        //获取字符流
        PrintWriter writer = response.getWriter();

        //4.判断
        if (select == null) {
            //添加数据
            mapper.add(user);
            //提交事务
            sqlSession.commit();
            //释放资源
            sqlSession.close();
            //提示信息
            writer.write("注册成功");
        } else {
            //提示信息
            writer.write("用户名已存在");
        }
    }
}

3.创建SqlSessionFactory代码优化 

public class SqlSessionFactoryUtils {
    private static SqlSessionFactory sqlSessionFactory;

    static {
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static SqlSessionFactory getSqlSessionFactory() {
        return sqlSessionFactory;
    }
}

 

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受用户名和密码
        String username1 = request.getParameter("username");
        String password1 = request.getParameter("password");

        //2.调用Mybatis完成查询
        //2.1获取SqlSessionFactory对象：从官网复制
//        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对象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        //2.4调用方法
        User select = mapper.select(username1, password1);
        //2.5释放资源
        sqlSession.close();

        //解析html，并解决中文乱码
        response.setContentType("text/html;charset=utf-8");
        //获取字符流
        PrintWriter writer = response.getWriter();

        //3.判断
        if (select != null) {
            writer.write("登录成功");
        } else {
            writer.write("登录失败");
        }
    }
}

@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受用户名和密码
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        //2.封装用户对象
        User user = new User();
        user.setUsername(username);
        user.setPassword(password);

        //3..调用Mybatis完成查询
        //3.1获取SqlSessionFactory对象：从官网复制
//        String resource = "mybatis-config.xml";
//        InputStream inputStream = Resources.getResourceAsStream(resource);
//        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
        //3.2获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.3获取mapper对象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        //3.4调用方法
        User select = mapper.selectByUsername(username);

        //解析html，并解决中文乱码
        response.setContentType("text/html;charset=utf-8");
        //获取字符流
        PrintWriter writer = response.getWriter();

        //4.判断
        if (select == null) {
            //添加数据
            mapper.add(user);
            //提交事务
            sqlSession.commit();
            //释放资源
            sqlSession.close();
            //提示信息
            writer.write("注册成功");
        } else {
            //提示信息
            writer.write("用户名已存在");
        }
    }
}

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原文地址: https://outofmemory.cn/langs/889849.html

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