Mybatis-Plus：快速开始（SpringBoot + Mybatis + Mybatis）

01:Mybatis-Plus：了解Mybatis-Plus、快速开始（Mybatis + Mybatis-Plus，Mybatis-Plus自动做了属性映射）

02：Mybatis-Plus：快速开始（Spring + Mybatis + Mabatis-Plus）

03：Mybatis-Plus：快速开始（SpringBoot + Mybatis + Mybatis）

pom.xml

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.6.4
         
    
    com.tian
    springboot-mybatis_plus
    0.0.1-SNAPSHOT
    springboot-mybatis_plus
    Demo project for Spring Boot
    
        1.8
    
    
        
            org.springframework.boot
            spring-boot-starter
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
        
            org.projectlombok
            lombok
            true
        
        
        
            com.baomidou
            mybatis-plus-boot-starter
            3.3.2
        
        
        
            mysql
            mysql-connector-java
            8.0.25
        
        
            org.slf4j
            slf4j-log4j12
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

log4j.properties

log4j.rootLogger=DEBUG,A1

log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=[%t] [%c]-[%p] %m%n

Navicat执行下列SQL语句

CREATE DATAbase mp;
USE mp;

-- 创建测试表
CREATE TABLE `tb_user` (
	`id` BIGINT ( 20 ) NOT NULL AUTO_INCREMENT COMMENT '主键ID',
	`user_name` VARCHAR ( 20 ) NOT NULL COMMENT '用户名',
	`password` VARCHAR ( 20 ) NOT NULL COMMENT '密码',
	`name` VARCHAR ( 30 ) DEFAULT NULL COMMENT '姓名',
	`age` INT ( 11 ) DEFAULT NULL COMMENT '年龄',
	`email` VARCHAR ( 50 ) DEFAULT NULL COMMENT '邮箱',
	PRIMARY KEY ( `id` ) 
) ENGINE = INNODB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8;

-- 插入测试数据
INSERT INTO `tb_user` ( `id`, `user_name`, `password`, `name`, `age`, `email` )
VALUES
	( '1', 'zhangsan', '123456', '张三', '18', 'test1@itcast.cn' );
INSERT INTO `tb_user` ( `id`, `user_name`, `password`, `name`, `age`, `email` )
VALUES
	( '2', 'lisi', '123456', '李四', '20', 'test2@itcast.cn' );
INSERT INTO `tb_user` ( `id`, `user_name`, `password`, `name`, `age`, `email` )
VALUES
	( '3', 'wangwu', '123456', '王五', '28', 'test3@itcast.cn' );
INSERT INTO `tb_user` ( `id`, `user_name`, `password`, `name`, `age`, `email` )
VALUES
	( '4', 'zhaoliu', '123456', '赵六', '21', 'test4@itcast.cn' );
INSERT INTO `tb_user` ( `id`, `user_name`, `password`, `name`, `age`, `email` )
VALUES
	( '5', 'sunqi', '123456', '孙七', '24', 'test5@itcast.cn' );

执行结果：

application.properties

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mp?useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=317525

package pojo;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data  // get / set方法
@NoArgsConstructor // 无参构造函数
@AllArgsConstructor // 有参构造函数
@TableName("tb_user")
public class User {
    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private String email;
}

UserMapper.java

package mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import pojo.User;

public interface UserMapper extends baseMapper {
    User findById(Long id);
}

SpringbootMybatisPlusApplicationTests

package com.tian.springbootmybatis_plus;

import mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import pojo.User;

import java.util.List;

@SpringBootTest
class SpringbootMybatisPlusApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelectList() {
        // 现在我们使用MP给我们提供的方法 null就表示没有查询条件 查询所有的数据出来
        List users = this.userMapper.selectList(null);
        for (User user : users) {
            System.out.println(user);
        }
    }
}

运行结果：