mybatis-plus的概念

1、定义

MyBatis-Plus（简称MP）是一个MyBatis的增强工具，在MyBatis的基础上只做增强不做改变，为简化开发、提高效率而生。

2、简单实例

（1）项目结构

（2）MySpringBootApplication.java

package cn.hwd.mp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MySpringBootApplication {

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

}
（3）User.java

package cn.hwd.mp.domain;

import java.util.Date;

import lombok.Data;

import com.baomidou.mybatisplus.annotations.TableField;
import com.baomidou.mybatisplus.annotations.TableId;
import com.baomidou.mybatisplus.annotations.TableName;
import com.baomidou.mybatisplus.enums.IdType;
import com.fasterxml.jackson.annotation.JsonFormat;

@Data
@TableName(value = "user")
public class User {

@TableId(value = "id", type = IdType.AUTO) // 主键自增长
private Integer id;
@TableField(value = "name")
private String name;
@TableField(value = "age")
private Integer age;
@JsonFormat(pattern="yyyyMMddHHmmssSSS", timezone="GMT+8")
@TableField(value = "birth")
private Date birth;

}
（4）UserMapper.java

package cn.hwd.mp.mapper;

import org.apache.ibatis.annotations.Mapper;

import com.baomidou.mybatisplus.mapper.BaseMapper;

import cn.hwd.mp.domain.User;

@Mapper
public interface UserMapper extends BaseMapper<User> {

}
（5）UserMapperTests.java

package cn.hwd.mp.mapper;

import java.util.Date;
import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.baomidou.mybatisplus.mapper.EntityWrapper;
import com.baomidou.mybatisplus.plugins.Page;

import cn.hwd.mp.domain.User;

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTests {

@Autowired
private UserMapper userMapper;

@Test
public void testSelectList() {
List<User> userList = userMapper.selectList(
new EntityWrapper<User>().eq("name", "Tom"));
System.out.println(userList);
}

@Test
public void testSelectPage() {
List<User> userList = userMapper.selectPage(
new Page<User>(1, 10),
new EntityWrapper<User>().eq("name", "Tom"));
System.out.println(userList);
}

@Test
public void testSelectById() {
User user = userMapper.selectById(1);
System.out.println(user);
}

@Test
public void testInsert() {
User user = new User();
user.setName("Diana");
user.setAge(18);
user.setBirth(new Date());
int result = userMapper.insert(user);
System.out.println(result);
}

@Test
public void testUpdateById() {
User user = new User();
user.setId(1);
user.setName("Jack");
user.setAge(28);
user.setBirth(new Date());
int result = userMapper.updateById(user);
System.out.println(result);
}

@Test
public void testDeleteById() {
int result = userMapper.deleteById(1);
System.out.println(result);
}

}
（6）application.properties

spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/hwd?useUnicode=true&characterEncoding=utf-8
spring.datasource.username = root
spring.datasource.password = mysql
（7）pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>cn.hwd</groupId>
<artifactId>mybatisplus01</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>mybatisplus01</name>
<url>http://www.example.com</url>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.4.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>1.4.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<version>1.4.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.16.10</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.30</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>2.2.0</version>
</dependency>
</dependencies>
</project>

mybatis-plus的概念

原文：https://www.cnblogs.com/minghuisheng/p/10770903.html