SpringBoot 整合Mybatis

mybatis标签介绍:https://blog.youkuaiyun.com/weixin_40950778/article/details/78655288

1.简介

Mybatis是一个半自动的ORM持久层框架，内部封装了JDBC。作为开发者只需要关注sql语句本身。MyBatis 是采用 ORM（Object Relational Mapping，对象关系映射）思想实现的持久化层框架。

特点：

• MyBatis 是半自动 ORM 框架。
• 将 SQL 定制抽取出来，以配置文件的方式交由开发人员编写。
• 封装了 预编译、设置参数、执行 SQL、封装结果等操作。
• 实现了 SQL 与 Java 编码分离。
• 只需要掌握 SQL 和 MyBatis 相关配置就可以使用，学习成本相对更低。
• 由于 SQL 需要由开发人员编写，方便维护与优化。

2.项目创建

先要创建test数据库
创建表sys_user

create table sys_user(
    name varchar(20),
    age int);

2.1 pom文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.porridge</groupId>
    <artifactId>test-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>test-mybatis</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>

        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.4</version>
        </dependency>

        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.2 application.yml文件

spring:
  datasource:
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&useSSL=true&serverTimezone=Asia/Shanghai
mybatis:
  #配置xml位置
  mapper-locations: classpath:mapping/*Mapping.xml
  #标注实体类位置
  type-aliases-package: com.porrdige.www.pojo
  #驼峰命名
  configuration:
    map-underscore-to-camel-case: true

2.3 实体类（SysUser）

@NoArgsConstructor
@AllArgsConstructor
@Data
@Component
public class SysUser {
    String name;
    int age;
}

2.4 接口（SysUserMapper）

@Mapper
@Repository
public interface SysUserMapper {
    /**
     * <p>插入数据</P>
     */
    int insert(String name, int age);
    
    /**
     * <p>查询所有数据</P>
     */
    List<SysUser> allUser();
    
    /**
     * <p>修改数据</P>
     */
    int updateAge(String name, int age);

    /**
     * <p>删除数据</P>
     */
    int delete(String name);
    
    
}

2.4 mybatis配置文件（SysUserMapping.xml）

<?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="com.porridge.www.mapper.SysUserMapper">

    <resultMap id="UserMap" type="com.porridge.www.pojo.SysUser">
        <result column="name" jdbcType="VARCHAR" property="name"/>
        <result column="age" jdbcType="INTEGER" property="age"/>
    </resultMap>
    
    <insert id="insert">
        insert into sys_user (
            name, age
        ) values (
         #{name}, #{age}
        )
    </insert>

    <select id="allUser" resultMap="UserMap">
        select * from sys_user
    </select>

    <update id="updateAge">
        update sys_user set age=#{age} where name=#{name}
    </update>

    <delete id="delete">
        delete from sys_user where name =#{name}
    </delete>
</mapper>

2.5 测试

package com.porridge.www;

import com.porridge.www.mapper.SysUserMapper;
import com.porridge.www.pojo.SysUser;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

@SpringBootTest
class TestMybatisApplicationTests {

    @Autowired
    SysUserMapper sysUserMapper;

    @Test
    void insert() {
        int num = sysUserMapper.insert("p", 11);
        System.out.println("插入条数"+num);
    }

    @Test
    void select(){
        List<SysUser> sysUsers = sysUserMapper.allUser();
        for (SysUser sysUser : sysUsers) {
            System.out.println(sysUser);
        }
    }
    @Test
    void Update(){
        int updateAge = sysUserMapper.updateAge("porridge", 99);
        System.out.println("修改条数："+updateAge);
    }
    @Test
    void delete(){
        int del = sysUserMapper.delete("p");
        System.out.println("删除条数："+del);
    }

}