mybatisplus入门

创建数据库haoke

CREATE TABLE `user` (
`id` bigint(20) NOT NULL COMMENT '主键ID', `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 DEFAULT CHARSET=utf8; 
-- 插入数据 
INSERT INTO `user` (`id`, `name`, `age`, `email`) VALUES ('1', 'Jone', '18', 'test1@baomidou.com'); INSERT INTO `user` (`id`, `name`, `age`, `email`) VALUES ('2', 'Jack', '20', 'test2@baomidou.com'); INSERT INTO `user` (`id`, `name`, `age`, `email`) VALUES ('3', 'Tom', '28', 'test3@baomidou.com'); INSERT INTO `user` (`id`, `name`, `age`, `email`) VALUES ('4', 'Sandy', '21', 'test4@baomidou.com'); INSERT INTO `user` (`id`, `name`, `age`, `email`) VALUES ('5', 'Billie', '24', 'test5@baomidou.com');

groupid:cn.itcast.mybatisplus
artifactid:itcast-mybatis-plus

    4.0.0

    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.0.RELEASE
    

    cn.itcast.mybatisplus
    itcast-mybatis-plus
    1.0-SNAPSHOT

    
        
            org.springframework.boot
            spring-boot-starter
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
        
        
            com.baomidou
            mybatis-plus-boot-starter
            3.0.5
        
        
        
            mysql
            mysql-connector-java
            5.1.47
        
        
        
            org.projectlombok
            lombok
            true
            1.18.4
        
    

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

spring.application.name = itcast-mybatis-plus

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://192.168.58.136:3306/haoke?useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=root

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import lombok.Data;

@Data
public class User {

    @TableId(value = "ID", type = IdType.AUTO)
    private Long id;
    private String name;
    private Integer age;
    private String email;

}

import cn.itcast.mybatisplus.pojo.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;

public interface UserMapper extends BaseMapper {

}

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@MapperScan("cn.itcast.mybatisplus.mapper") //设置mapper接口的扫描包
@SpringBootApplication
public class MyApplication {

    
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }

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

}

import cn.itcast.mybatisplus.pojo.User;
import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
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 java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMaperTest {
	 @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelect(){
        List users = this.userMapper.selectList(null);
        for (User user : users) {
            System.out.println(user);
        }
    }
}

测试结果

在MybatisPlus中，BaseMapper中定义了一些常用的CRUD方法，当我们自定义的Mapper接口继承BaseMapper后即可拥有了这些方法。

public interface BaseMapper {

int insert(T entity);

int deleteById(Serializable id);

int deleteByMap(@Param(Constants.COLUMN_MAP) Map columnMap);

int delete(@Param(Constants.WRAPPER) Wrapper queryWrapper);

int deleteBatchIds(@Param(Constants.COLLECTION) Collection idList);

int updateById(@Param(Constants.ENTITY) T entity);

int update(@Param(Constants.ENTITY) T entity, @Param(Constants.WRAPPER)
Wrapper updateWrapper);

T selectById(Serializable id);

List selectBatchIds(@Param(Constants.COLLECTION) Collection idList);

List selectByMap(@Param(Constants.COLUMN_MAP) Map
columnMap);

T selectOne(@Param(Constants.WRAPPER) Wrapper queryWrapper);

Integer selectCount(@Param(Constants.WRAPPER) Wrapper queryWrapper);

List selectList(@Param(Constants.WRAPPER) Wrapper queryWrapper);

List> selectMaps(@Param(Constants.WRAPPER) Wrapper
queryWrapper);

List