Mybatis的简单使用(增、删、改、查)

MyBatis开发步骤

• 添加MyBatis坐标
• 创建数据表
• 编写实体类
• 编写映射文件
• 编写核心文件

导入Mybatis相关坐标

   <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.15</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.4</version>
        </dependency>

创建User数据表

编写User实体类

package com.domain;

public class User {

    private int id;
    private String username;
    private String password;


    public int getId() {
        return id;
    }

    public void setId(int 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 + '\'' +
                '}';
    }
}

编写UserMapper.xml映射文件

映射文件概述

<?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">
<mapper namespace="userMapper">
    <!--    查询操作-->
    <select id="findAll" resultType="com.domain.User">
        select * from User
    </select>
    <!--    插入操作-->
    <insert id="add" parameterType="com.domain.User">
        insert into User values (#{id},#{username},#{password})
    </insert>
    <!--    修改数据-->
    <update id="update" parameterType="com.domain.User">
        update User set password = #{password} where username=#{username}
    </update>
    <!--    删除操作-->
    <delete id="delete" parameterType="com.domain.User">
        delete from User where username=#{username}
    </delete>

</mapper>

编写sqlMapConfig.xml核心文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">


<!--数据源环境-->
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/one"/>
                <property name="username" value="root"/>
                <property name="password" value="admin123"/>
            </dataSource>
        </environment>
    </environments>

<!--    加载映射文件-->
    <mappers>
        <mapper resource="com/mapper/UserMapper.xml"></mapper>
    </mappers>

</configuration>

测试

package com.test;

import com.domain.User;
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.junit.jupiter.api.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestMyBatis {


    //    查询操作
    @Test
    public void select() throws IOException {

//        加载核心配置文件
        InputStream resource = Resources.getResourceAsStream("sqlMapConfig.xml");
//        获得sqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resource);
//        获得SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
//        执行sql语句
        List<User> list = sqlSession.selectList("userMapper.findAll");
        System.out.println(list);
//        释放资源
        sqlSession.close();

    }

    //    插入操作
    @Test
    public void add() throws IOException {
//        自定义数据
        User user = new User();
        user.setUsername("zhao");
        user.setPassword("110");
        //        加载核心配置文件
        InputStream resource = Resources.getResourceAsStream("sqlMapConfig.xml");
//        获得sqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resource);
//        获得SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
//        执行sql语句
        sqlSession.insert("userMapper.add", user);
//        事务提交
        sqlSession.commit();
//        释放资源
        sqlSession.close();

    }

    //    修改操作
    @Test
    public void update() throws IOException {
        //        自定义数据
        User user = new User();
        user.setUsername("zhao");
        user.setPassword("9");
        //        加载核心配置文件
        InputStream resource = Resources.getResourceAsStream("sqlMapConfig.xml");
//        获得sqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resource);
//        获得SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
//        执行sql语句
        sqlSession.update("userMapper.update", user);
//        事务提交
        sqlSession.commit();
//        释放资源
        sqlSession.close();

    }

    //    删除操作
    @Test
    public void delete() throws IOException {
        //        自定义数据
        User user = new User();
        user.setUsername("zhao");
        //        加载核心配置文件
        InputStream resource = Resources.getResourceAsStream("sqlMapConfig.xml");
//        获得sqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resource);
//        获得SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
//        执行sql语句
        sqlSession.delete("userMapper.delete", user);
//        事务提交
        sqlSession.commit();
//        释放资源
        sqlSession.close();

    }

}