MybatisPlus基本使用

假设你已经建立数据表

在SpringBoot中引入相关依赖：

<!-- SpringBoot单元测试 -->
<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
</dependency>
<!-- Web开发场景启动器-->
<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- SpringBoot场景启动器-->
<dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.2</version>
</dependency>
<!-- lombok 简化实体类的编写-->
<dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
</dependency>
<!-- 数据库驱动 -->
 <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.29</version>
</dependency>

<!-- MybatisPlus依赖 -->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.2</version>
</dependency>

配置数据库信息：

在application.yaml 中配置：

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    password: zqh123
    username: root
    driver-class-name: com.mysql.cj.jdbc.Driver

编写Mapper接口

目录：com.blog.qh.mybatisplus.mapper.UserMapper

UserMapper继承MybatisPlus的BaseMapper接口，里面是对单表的CURD操作。

Spring动态生成UserMapper接口代理对象

package com.blog.qh.mybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.blog.qh.mybatisplus.pojo.User;
import org.springframework.stereotype.Repository;


@Repository
public interface UserMapper extends BaseMapper<User> {
        

}

添加Mapper包扫描

在SpringBoot启动入口类中：

package com.blog.qh.mybatisplus;


import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.blog.qh.mybatisplus.mapper")
public class MyBatisPlusApplication {

    public static void main(String[] args) {
        SpringApplication.run(MyBatisPlusApplication.class,args);
    }
}

测试

package com.blog.qh.mybatisplus;


import com.blog.qh.mybatisplus.mapper.UserMapper;
import com.blog.qh.mybatisplus.pojo.User;
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
public class TestMybatisPlus {
    @Autowired
    UserMapper userMapper;
    @Test
    public void TestAllEle() {
        // 这个参数是条件查询，我们不需要条件筛选，参数为null查全部
        List<User> users = userMapper.selectList(null);
        for(User user : users) {
            System.out.println(user);
        }
    }
}