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。本文将介绍在springboot中使用mybatisplus。

1、前提约束

• 在mysql数据库中的test数据库实例下有一张表user，初始化语句如下：

DROP TABLE IF EXISTS user;
CREATE TABLE user
(
    id INT(20) NOT NULL,
    name VARCHAR(30) ,
    age INT(11),
    PRIMARY KEY (id)
);
INSERT INTO user (id, name, age) VALUES
(1, 'ali', 18),
(2, 'xiaoli', 20),
(3, 'zhangli', 28),
(4, 'xiaoni', 21),
(5, 'zhang', 24);

2、操作步骤

• 完成springboot创建web项目 https://www.jianshu.com/p/de979f53ad80
  注意，作者使用的springboot版本是2.2.6.RELEASE
• 加入依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.1.tmp</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

• 配置application.yml

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: zhangli
logging:
    level:
      net.wanho: DEBUG
server:
  port: 8088

• 在主启动类统计目录下创建User.java

import lombok.Data;

@Data
public class User {
    private Integer id;
    private String name;
    private Integer age;
}

• 在主启动类同级目录下创建UserMapper.java接口

import org.springframework.stereotype.Repository;
import tk.mybatis.mapper.common.Mapper;

@Repository
public interface UserMapper extends Mapper<User> {
}

• 在主启动类同级目录下创建UserController.java

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import tk.mybatis.mapper.entity.Example;

import javax.annotation.Resource;
import java.util.List;

@RestController
public class UserController {

    @Resource
    private UserMapper userMapper;


    @GetMapping("/list")
    public List<User> list() {

        Example example = new Example(User.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andLike("name","%li%");
        criteria.andBetween("age",2,20);
        List<User> list = userMapper.selectByExample(example);
        return list;
    }

    @GetMapping("/page")
    public PageInfo<User> page() {

        PageHelper.startPage(1, 2);
        List<User> list = userMapper.selectAll();
        PageInfo<User> pageInfo = new PageInfo<>(list);
        return pageInfo;
    }
}

• 在主启动类上面加入Mapper扫描

@MapperScan("net.wanho")//注意，请读者根据自己的实际情况设置扫描路径

以上就是在springboot中使用mybatisplus的过程。