mybatis-plus 笔记

依赖

查看代码

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>mybatis-plus-boot-starter</artifactId>
  <version>3.4.3.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.27</version>
</dependency>

配置

src/main/java/com/example/mybatisplus/config/MybatisPlusConfig.java

查看代码

package com.example.mybatisplus.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableTransactionManagement
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //字段默认赋值
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        //分页
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return interceptor;
    }

}

src/main/resources/application.yml

查看代码

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mybatis-plus?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
    username: root
    password: 123456

mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  global-config:
    db-config:
      logic-delete-value: 1
      logic-not-delete-value: 0
      logic-delete-field: deleted
  mapper-locations: classpath:/mappers/*Mapper.xml
  type-aliases-package: com.example.mybatisplus.pojo

更新和删除填充值

src/main/java/com/example/mybatisplus/handler/MyMetaObjectHandler.java

查看代码

package com.example.mybatisplus.handler;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.sql.Timestamp;
import java.util.Date;

@Slf4j
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
//        log.info("insert fill");
        this.setFieldValByName("gmt_create", new Timestamp(new Date().getTime()), metaObject);
//        this.setFieldValByName("create_time", new Timestamp(new Date().getTime()), metaObject);
        this.setFieldValByName("gmt_modified", new Timestamp(new Date().getTime()), metaObject);
//        System.out.println(metaObject.getOriginalObject());
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        log.info("update fill");
        this.setFieldValByName("gmt_modified", new Timestamp(new Date().getTime()), metaObject);
    }
}

 

Mapper

src/main/java/com/example/mybatisplus/mapper/IUserMapper.java

查看代码

package com.example.mybatisplus.mapper;


import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.mybatisplus.pojo.User;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface IUserMapper extends BaseMapper<User> {
    User selectOnly(int age);
}

src/main/resources/mappers/UserMapper.xml

查看代码

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mybatisplus.mapper.IUserMapper">
    <select id="selectOnly" resultType="User">
        select id,name,age,email
        from user
        where deleted = 0 and age > #{age} limit 1
    </select>
</mapper>

Pojo

src/main/java/com/example/mybatisplus/pojo/User.java

查看代码

package com.example.mybatisplus.pojo;

import com.baomidou.mybatisplus.annotation.*;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;

import java.sql.Timestamp;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Accessors(chain = true)
public class User {
    @TableId(type= IdType.AUTO)
    private Long id;
    private String name;
    private Integer age;
    private String email;

//    @TableField(fill = FieldFill.INSERT)
    private Timestamp gmt_create;
//    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Timestamp gmt_modified;

    @Version
    private int version;

    private int deleted;
}