Spring Boot学习02

本文在上一篇文章的基础上，继续完成Mybatis的“增、删、改”的操作。

修改3.3的Mybatis映射文件，添加三个新的sql语句：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--        namespace 所对应的是一个接口的全限定名-->
<mapper namespace="com.example.demo.mapper.IUserMapper">
    <select id="getUserById" resultType="com.example.demo.model.Users">
        SELECT id,last_name,gender,email FROM tbl_employee WHERE id = #{id}
    </select>
    <update id="updateUser">
        UPDATE tbl_employee set last_name=#{last_name},gender=#{gender},email=#{email}
        where id=#{id}
    </update>
    
    <delete id="delUser">
        DELETE from tbl_employee where id=#{id}
    </delete>

    <insert id="addUser">
        INSERT into tbl_employee values(#{id},#{last_name},#{gender},#{email})
    </insert>
</mapper>

修改3.4节的接口文件，增加三个方法：

package com.example.demo.mapper;

import com.example.demo.model.Users;
import org.springframework.stereotype.Component;

@Component
public interface IUserMapper {
    //查询
    public Users getUserById(Integer id);

    //更新
    public boolean updateUser(Users user);

    //删除
    public boolean delUser(Integer id);

    //新增
    public boolean addUser(Users user);
}

修改第4节的Mybatis接口文件，增加45、75、105行的三个方法，对应映射文件中的更新、删除以及新增操作：

package com.example.demo.service;
import com.example.demo.mapper.IUserMapper;
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 org.springframework.stereotype.Service;
import java.io.IOException;
import java.io.InputStream;
@Service
public class Users {

    public com.example.demo.model.Users getUserById(Integer id) throws IOException {

        // 读取mybatis-config.xml文件
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");

        // 初始化mybatis，创建SqlSessionFactory类的实例
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 创建Session实例
        SqlSession session = sqlSessionFactory.openSession();

        // 操作数据库方法一：获得xml映射文件中定义的操作语句
        // com.example.demo.model.Users s = session.selectOne("com.example.demo.mapper.IUserMapper.getUserById", 1);
        // 打印Student对象
        // System.out.println(s);

        // 操作数据库方法二：获得mapper接口的代理对象
        IUserMapper sm = session.getMapper(IUserMapper.class);
        // 直接调用接口的方法，查询id为1的Student数据
        com.example.demo.model.Users s2 = sm.getUserById(1);
        // 打印Peson对象
        // System.out.println(s2);

        // 提交事务
        session.commit();
        // 关闭Session
        session.close();

        return s2;
        //return userMapper.getUserById(id);
    }

    public boolean updateUser(com.example.demo.model.Users user) throws IOException {
        // 读取mybatis-config.xml文件
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");

        // 初始化mybatis，创建SqlSessionFactory类的实例
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 创建Session实例
        SqlSession session = sqlSessionFactory.openSession();

        // 操作数据库方法一：获得xml映射文件中定义的操作语句
        // com.example.demo.model.Users s = session.selectOne("com.example.demo.mapper.IUserMapper.getUserById", 1);
        // 打印Student对象
        // System.out.println(s);

        // 操作数据库方法二：获得mapper接口的代理对象
        IUserMapper sm = session.getMapper(IUserMapper.class);
        // 直接调用接口的方法，查询id为1的Student数据
        boolean b = sm.updateUser(user);
        // 打印Peson对象
        // System.out.println(s2);

        // 提交事务
        session.commit();
        // 关闭Session
        session.close();

        return b;
    }

    public boolean delUser(Integer id) throws IOException {
        // 读取mybatis-config.xml文件
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");

        // 初始化mybatis，创建SqlSessionFactory类的实例
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 创建Session实例
        SqlSession session = sqlSessionFactory.openSession();

        // 操作数据库方法一：获得xml映射文件中定义的操作语句
        // com.example.demo.model.Users s = session.selectOne("com.example.demo.mapper.IUserMapper.getUserById", 1);
        // 打印Student对象
        // System.out.println(s);

        // 操作数据库方法二：获得mapper接口的代理对象
        IUserMapper sm = session.getMapper(IUserMapper.class);
        // 直接调用接口的方法，查询id为1的Student数据
        boolean b = sm.delUser(1);
        // 打印Peson对象
        // System.out.println(s2);

        // 提交事务
        session.commit();
        // 关闭Session
        session.close();

        return b;
    }

    public boolean addUser(com.example.demo.model.Users user) throws IOException {
        // 读取mybatis-config.xml文件
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");

        // 初始化mybatis，创建SqlSessionFactory类的实例
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 创建Session实例
        SqlSession session = sqlSessionFactory.openSession();

        // 操作数据库方法一：获得xml映射文件中定义的操作语句
        // com.example.demo.model.Users s = session.selectOne("com.example.demo.mapper.IUserMapper.getUserById", 1);
        // 打印Student对象
        // System.out.println(s);

        // 操作数据库方法二：获得mapper接口的代理对象
        IUserMapper sm = session.getMapper(IUserMapper.class);
        // 直接调用接口的方法，查询id为1的Student数据
        boolean b = sm.addUser(user);
        // 打印Peson对象
        // System.out.println(s2);

        // 提交事务
        session.commit();
        // 关闭Session
        session.close();

        return b;
    }
}

修改第5节的Controller中的内容，增加三个Action：

package com.example.demo.controller;

import com.example.demo.model.Users;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.io.IOException;

@RestController
public class UserController {

    @Autowired
    com.example.demo.service.Users userService;

    @RequestMapping("/user/{id}")
    public String getUserById(@PathVariable Integer id) throws IOException {

        com.example.demo.model.Users users = userService.getUserById(id);
        return users.getLast_name();
    }

    @RequestMapping("/updateuser")
    public String updateUser() throws IOException {
        Users user = new com.example.demo.model.Users(1,"yangasen",1,"yangasen@hotmial.com");
        boolean b = userService.updateUser(user);
        return b + "";
    }

    @RequestMapping("/deluser/{id}")
    public String delUser(@PathVariable Integer id) throws IOException {
        boolean b = userService.delUser(id);
        return b + "";
    }

    @RequestMapping("/newuser")
    public String newUser() throws IOException {
        Users user = new com.example.demo.model.Users(1,"yangasen",1,"yangasen@hotmial.com");
        boolean b = userService.addUser(user);
        return b + "";
    }
}

测试：

更新操作：使用[http://localhost:8080/updateuser]

删除操作：使用[http://localhost:8080/deluser/1]

新增操作：使用[http://localhost:8080/newuser]

Spring Boot + MyBatis连接MySQL数据库的“增删改查”基本操作，已经完成。