整合MyBatis-Plus_整合mybatisplus-优快云博客

本文链接：https://blog.youkuaiyun.com/zhangruibo_code/article/details/129385714

文章介绍了MyBatis-Plus的使用，包括引入依赖、配置数据库、创建启动类、定义实体类和Mapper接口，详细讲解了主键策略如ID_WORKER和自增策略，并展示了CRUD操作和条件构造器的使用。此外，还涵盖了如何封装Service层以及配置分页插件进行分页查询。

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文章目录

1、依赖
2、配置文件
3、启动类
4、实体类
5、Mapper
6、主键策略
7、条件构造器
8、MyBatis-Plus封装service层
9、分页插件

MyBatis-Plus (opens new window)（简称 MP）是一个 MyBatis (opens new window)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。

1、依赖

	<!--mybatis-plus 持久层-->
	<dependency>
    	<groupId>com.baomidou</groupId>
    	<artifactId>mybatis-plus-boot-starter</artifactId>
    	<version>3.5.3.1</version>
    </dependency>
	<!--mysql-->
    <dependency>
    	<groupId>mysql</groupId>
    	<artifactId>mysql-connector-java</artifactId>
    	<version>8.0.30</version>
    </dependency>

2、配置文件

配置 MySQL 数据库的相关配置及Mybatis-Plus日志

application.yml

spring:
  application:
    name: service-oa
  profiles:
    active: dev

application-dev.yml

server:
  port: 8800
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 查看日志
  global-config:
    db-config:
      logic-delete-value: 1
      logic-not-delete-value: 0
spring:
  datasource:
    type: com.zaxxer.hikari.HikariDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/guigu-oa?serverTimezone=GMT%2B8&useSSL=false&characterEncoding=utf-8
    username: root
    password: 12345
  jackson:
    date-format: yyyy-MM-dd HH:mm:ss
    time-zone: GMT+8

3、启动类

在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹

package com.atguigu;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@ComponentScan("com.atguigu")
@MapperScan("com.atguigu.*.mapper")
public class ServiceAuthApplication {

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

}

4、实体类

package com.atguigu.model.system;

import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import com.atguigu.model.base.BaseEntity;
import lombok.Data;

@Data
@TableName("sys_role")
public class SysRole extends BaseEntity {
   
   private static final long serialVersionUID = 1L;

   //角色名称
   @TableField("role_name")
   private String roleName;

   //角色编码
   @TableField("role_code")
   private String roleCode;

   //描述
   @TableField("description")
   private String description;

}

@Data
public class BaseEntity implements Serializable {

    @TableId(type = IdType.AUTO)
    private Long id;

    @TableField("create_time")
    private Date createTime;

    @TableField("update_time")
    private Date updateTime;

    @TableLogic //逻辑删除
    @TableField("is_deleted")
    private Integer isDeleted;

    @TableField(exist = false)
    private Map<String,Object> param = new HashMap<>();
}

5、Mapper

com.baomidou.mybatisplus.core.mapper.BaseMapper这是Mybatis-Plus提供的默认Mapper接口

package com.atguigu.auth.mapper;

import com.atguigu.model.auth.SysRole;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface SysRoleMapper extends BaseMapper<SysRole> {

}

6、主键策略

6.1、ID_WORKER

MyBatis-Plus默认的主键策略是：ID_WORKER 全局唯一ID

6.2、自增策略

要想主键自增需要配置如下主键策略

需要在创建数据表的时候设置主键自增
实体字段中配置 @TableId(type = IdType.AUTO)

@TableId(type = IdType.AUTO)
private Long id;

其它主键策略：分析 IdType 源码可知

public enum IdType {
     /**
     * 数据库ID自增
     */
    AUTO(0),
    
    /**
     * 该类型为未设置主键类型
     */
    NONE(1),
    
    /**
     * 用户输入ID
     * 该类型可以通过自己注册自动填充插件进行填充
     */    
    INPUT(2),
    
    /**
     * 全局唯一ID
     */    
    ASSIGN_ID(3),
    
    /**
     * 全局唯一ID (UUID)
     */
    ASSIGN_UUID(4),
    
    /** @deprecated */
    @Deprecated
    ID_WORKER(3),
    /** @deprecated */
    @Deprecated
    ID_WORKER_STR(3),
    /** @deprecated */
    @Deprecated
    UUID(4);
    private final int key;
    private IdType(int key) {
        this.key = key;
    }
    public int getKey() {
        return this.key;
    }
}

6.3、CURD测试

int result = sysRoleMapper.insert(sysRole);
System.out.println(result); //影响的行数
System.out.println(sysRole); //id自动回填

int result = sysRoleMapper.updateById(sysRole);
System.out.println(result);

/**
 * application-dev.yml 加入配置
 * 此为默认值，如果你的默认值和mp默认的一样，则不需要该配置
 * mybatis-plus:
 *   global-config:
 *     db-config:
 *       logic-delete-value: 1
 *       logic-not-delete-value: 0
 */
int result = sysRoleMapper.deleteById(2L);
System.out.println(result);


int result = sysRoleMapper.deleteBatchIds(Arrays.asList(1, 1));
System.out.println(result);

7、条件构造器

LambdaQueryWrapper<SysRole> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(SysRole::getRoleCode, "role");
List<SysRole> users = sysRoleMapper.selectList(queryWrapper);
System.out.println(users);

8、MyBatis-Plus封装service层

8.1、添加service接口

com.baomidou.mybatisplus.extension.service.IService这是Mybatis-Plus提供的默认Service接口

package com.atguigu.auth.service;

import com.atguigu.model.auth.SysRole;
import com.baomidou.mybatisplus.extension.service.IService;

import java.util.List;

public interface SysRoleService extends IService<SysRole> {

}

8.2、添加service接口实现

com.baomidou.mybatisplus.extension.service.impl.ServiceImpl这是Mybatis-Plus提供的默认Service接口实现

package com.atguigu.auth.service.impl;

import com.atguigu.auth.mapper.SysRoleMapper;
import com.atguigu.auth.service.SysRoleService;
import com.atguigu.model.auth.SysRole;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;

import java.util.List;

public class SysRoleServiceImpl extends ServiceImpl<SysRoleMapper, SysRole> implements SysRoleService {

}

8.3、测试service接口

//UserMapper 中的 selectList() 方法的参数为 MP 内置的条件封装器 Wrapper
//所以不填写就是无任何条件
List<SysRole> users = sysRoleService.list();
users.forEach(System.out::println);

boolean result = sysRoleService.save(sysRole);
System.out.println(result); //影响的行数
System.out.println(sysRole); //id自动回填

boolean result = sysRoleService.updateById(sysRole);
System.out.println(result);

boolean result = sysRoleService.removeById(2L);
System.out.println(result);

LambdaQueryWrapper<SysRole> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.ge(SysRole::getRoleCode, "role");
List<SysRole> users = sysRoleService.list(queryWrapper);
System.out.println(users);

9、分页插件

9.1、配置分页插件

我们将@MapperScan(“com.atguigu.auth.mapper”)提取到该配置类上面，统一管理，启动类和yaml配置文件就不需要了

package com.atguigu.common.config.mp;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.autoconfigure.ConfigurationCustomizer;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@MapperScan("com.atguigu.auth.mapper")
public class MybatisPlusConfig {

    /**
     * 新的分页插件,一缓和二缓遵循mybatis的规则,需要设置 MybatisConfiguration#useDeprecatedExecutor = false 避免缓存出现问题(该属性会在旧插件移除后一同移除)
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }

    @Bean
    public ConfigurationCustomizer configurationCustomizer() {
        return configuration -> configuration.setUseDeprecatedExecutor(false);
    }
}

9.2、分页controller

//条件分页查询
//page 当前页  limit 每页显示记录数
//SysRoleQueryVo 条件对象
@ApiOperation("条件分页查询")
@GetMapping("{page}/{limit}")
public Result pageQueryRole(@PathVariable Long page,
                            @PathVariable Long limit,
                            SysRoleQueryVo sysRoleQueryVo) {
    //调用service的方法实现
    //1 创建Page对象，传递分页相关参数
    //page 当前页  limit 每页显示记录数
    Page<SysRole> pageParam = new Page<>(page,limit);

    //2 封装条件，判断条件是否为空，不为空进行封装
    LambdaQueryWrapper<SysRole> wrapper = new LambdaQueryWrapper<>();
    String roleName = sysRoleQueryVo.getRoleName();
    if(!StringUtils.isEmpty(roleName)) {
        //封装 like模糊查询
        wrapper.like(SysRole::getRoleName,roleName);
    }

    //3 调用方法实现
    IPage<SysRole> pageModel = sysRoleService.page(pageParam, wrapper);
    return Result.ok(pageModel);
}

9.3、配置日期时间格式

  jackson:
    date-format: yyyy-MM-dd HH:mm:ss
    time-zone: GMT+8