springboot集成mybatis-plus

 

 

springboot项目 先导入相关依赖mybatis-plus相关依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.0.5</version>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <scope>runtime</scope>
</dependency>
加快实体类开发使用lombok

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

 

 2  端口号和数据库配置

server:
  port: 8080

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: "131412"
    url: jdbc:mysql://localhost:3306/user?serverTimezone=GMT%2B8&useSSL=false&useUnicode=true&characterEncoding=UTF-8

3创建实体类

导入lombok

 

 

 

 

 4写一个UserMapper接口

package com.example.demo6.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo6.pojo.user;
import org.springframework.stereotype.Repository;
//代表持久层 继承BaseMapper后 就有了基本的曾删改查等功能
@Repository
public interface UserMapper extends BaseMapper<user> {


}

 

 

 5主启动类扫描mapper接口

 

 6测试类测试 查询全部数据

 

 7配置日志

mybatis-plus:  configuration:    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

8实现增删改查

插入一条数据

@Test
    public void  testInsert(){
    user myuser=new user();
    myuser.setUserName("萌萌");
    myuser.setPassWord(333344);
    myuser.setRealName("w哈哈哈哈哈v");

     int  result= userMapper.insert(myuser);
    System.out.println(result);//受影响的行数
    System.out.println(myuser);//id自动生成
    }

主键自增策略

 

在实体类上加注解 改变主键自增策略

 

 

通过id修改一条数据

@Test
    public  void  testUpdate(){
        user myuser1=new user();
        myuser1.setId(1L);
        myuser1.setUserName("黄现强");
        myuser1.setPassWord(1314);
      int i= userMapper.updateById(myuser1);
    System.out.println(i);


}

 日期自动填充

在实体类上添加属性

@Data
public class user {
    private  long id;
    private  String userName;
    private  int passWord;
    private  String realName;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date createTime;
    @TableField(fill = FieldFill.INSERT)
    private  Date updateTime;

}

编写自动填充处理类

@Slf4j
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
        log.info("开始填充");
        this.setFieldValByName("createTime",new Date(),metaObject);
        this.setFieldValByName("updateTime",new Date(),metaObject);

    }

    @Override
    public void updateFill(MetaObject metaObject) {
        log.info("更新填充");
        this.setFieldValByName("updateTime",new Date(),metaObject);

    }
}

 

 

数据查询

@Test
 2     public  void  testSearch(){
 3 //        通过id查询单个数据
 4      user  searchUser= userMapper.selectById(2);
 5     System.out.println(searchUser);
 6 }
 7 @Test
 8     public  void testSearch1(){
 9 //      查询多条记录
10         List<user>  users= userMapper.selectBatchIds(Arrays.asList(6,7));
11           users.forEach(System.out::println);
12 }
13     @Test
14     public  void testSearch2(){
15 //      条件查询
16         HashMap<String,Object> map= new HashMap<>();
17         map.put("user_name","黄现强");
18      List<user>    users= userMapper.selectByMap(map);
19         users.forEach(System.out::println);
20     }

　　删除数据

//    删除单条记录
 @Test
    public  void testDelete(){
      int result=   userMapper.deleteById(8L);
     System.out.println(result);

 }
// 批量删除
 @Test
    public void testDeletes(){
        int  result  =userMapper.deleteBatchIds(Arrays.asList(6,9));
     System.out.println(result);
 }
//通过map删除
    @Test
    public void deleteBymap(){
                HashMap<String,Object>  map=new HashMap<>();
                map.put("user_name","萌萌");
                userMapper.deleteByMap(map);

     }

9性能分析

配置当前环境为开发环境

 

 在配置类中编写性能拦截器

package com.example.demo6.config;

import com.baomidou.mybatisplus.extension.plugins.PerformanceInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@EnableTransactionManagement
@MapperScan("com.example.demo6.mapper")
public class mybatisplusconfig {
//性能分析拦截器
    @Bean
    @Profile({"dev","test"})
    public PerformanceInterceptor performanceInterceptor(){
          PerformanceInterceptor  performanceInterceptor=new PerformanceInterceptor();
          performanceInterceptor.setFormat(true);//输出sql语句模板化
          performanceInterceptor.setMaxTime(100);//最大运行时间
          return performanceInterceptor;
    }

}

 

测试结果

 

10条件查询器wrapepr

  @Test
    public void  wrapper2(){
//        条件查询器wrapper
        QueryWrapper<user> wrapper = new QueryWrapper<>();
        wrapper.between("id",12,15);//查询条件
        List<user> result= userMapper.selectList(wrapper);
       result.forEach(System.out::println);
       
    }

}