一、Wrapper介绍

二、QueryWrapper的方法

三、目录结构

（1）目录

1、实体类

2、Mapper接口层

3、AnimalServiceImpl服务实现层

4、IAnimalService服务类

5、application.yml配置

（2）数据库

四、实例

（1）eq、ne

（2）gt、ge、lt、le

（3）between、notbetween

（4）like、notLike、likeLeft、likeRight

（5）isNull、isNotNull

（6）in、notIn

（7）inSql、notInSql

（8）or、and

（9）exists、notExists

（10）orderByAsc、orderByDesc

一、Wrapper介绍

在Mybatis-Plus（MP）中，简单的查询可以使用MP已经封装好的API来实现，但复杂的查询语句可以通过MP提供的Wrapper来进行封装。

Wrapper继承体系

Wrapper：条件构造抽象类，最顶端父类.

AbstractWrapper：用于查询条件封装，生成sql的where条件
QueryWrapper：Entity对象封装操作类，不是lambda语法
UpdateWrapper：Update条件封装，用于Entity对象更新操作
AbstractLambdaWrapper：Lambda语法使用Wrapper统一处理解析lambda获取column
LambdaQueryWrapper：用于Lambda语法使用的查询Wrapper
LambdaUpdateWrapper：Lambda更新封装Wrapper

二、QueryWrapper的方法

三、目录结构

（1）目录

1、实体类

@TableName("animal") ---> 关联的表名

@Data---->引入Lombok插件即可使用

@DateTimeFormat（pattern = "yyyy-MM-dd hh:mm:ss"）--->日期格式转换.

@DateTimeFormat注解加不加都可以，因为使用的是String类型.

package com.wrapper.entity;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
import lombok.EqualsAndHashCode;
import org.springframework.format.annotation.DateTimeFormat;



@TableName("animal")
@EqualsAndHashCode(callSuper = false)
@Data
public class Animal {

    
    private String name;

    
    private int age;

    
    private String alias;

    
    private String description;

    
    @DateTimeFormat(pattern = "yyyy-MM-dd hh:mm:ss")
    private String inputtime;

    
    @DateTimeFormat(pattern = "yyyy-MM-dd hh:mm:ss")
    private String updatetime;

}

2、Mapper接口层

package com.wrapper.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.wrapper.entity.Animal;
import org.apache.ibatis.annotations.Mapper;


@Mapper
public interface AnimalMapper extends baseMapper {
}

3、AnimalServiceImpl服务实现层

package com.wrapper.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wrapper.entity.Animal;
import com.wrapper.mapper.AnimalMapper;
import com.wrapper.service.IAnimalService;
import org.springframework.stereotype.Service;


@Service
public class AnimalServiceImpl extends ServiceImpl implements IAnimalService {
}

4、IAnimalService服务类

package com.wrapper.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.wrapper.entity.Animal;


public interface IAnimalService extends IService {
}

5、application.yml配置

spring:
  datasource:
    username: root
    password: 123456
    #?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/wapper_test_20211201?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

6、pom.xml配置

这里引用了thymeleaf和freemarker模板引擎依赖.去掉也可以.项目中并没有用到.



    4.0.0
    com.wrapper
    wrapper
    0.0.1-SNAPSHOT
    wrapper
    Demo project for Spring Boot

    
        1.8
        UTF-8
        UTF-8
        2.3.7.RELEASE
    

    
        
            org.springframework.boot
            spring-boot-starter-freemarker
        
        
            org.springframework.boot
            spring-boot-starter-thymeleaf
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            com.baomidou
            mybatis-plus-boot-starter
            3.4.2
        

        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
            
                
                    org.junit.vintage
                    junit-vintage-engine
                
            
        
        
            com.alibaba
            druid
            1.1.22
            compile
        
        
            mysql
            mysql-connector-java
        
        
            mysql
            mysql-connector-java
        
    

    
        
            
                org.springframework.boot
                spring-boot-dependencies
                ${spring-boot.version}
                pom
                import
            
        
    

    
        
            
                org.apache.maven.plugins
                maven-compiler-plugin
                3.8.1
                
                    1.8
                    1.8
                    UTF-8
                
            
            
                org.springframework.boot
                spring-boot-maven-plugin
                2.3.7.RELEASE
                
                    com.wrapper.WrapperApplication
                
                
                    
                        repackage
                        
                            repackage

（2）数据库

CREATE TABLE `animal` (
  `id` bigint NOT NULL AUTO_INCREMENT COMMENT '自增主键',
  `name` varchar(20) NOT NULL COMMENT '动物名称',
  `age` int DEFAULT NULL COMMENT '年龄',
  `alias` varchar(40) NOT NULL COMMENT '动物别名',
  `description` varchar(300) DEFAULT '' COMMENT '动物描述',
  `inputtime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '动物信息入机时间',
  `updatetime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '动物信息更新时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

四、实例

（1）eq、ne

eq：等于

    @Test
    void contextEq() {
        QueryWrapper queryWrapper = new QueryWrapper<>();
        //eq:等于
        //查询name等于狮子的数据.
        QueryWrapper eq = queryWrapper.eq("name", "狮子");
        Animal one = animalService.getOne(eq);
        System.out.println(one);
    }

Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09)

ne：不等于

 @Test
    void contextNe() {
        QueryWrapper queryWrapper = new QueryWrapper<>();
        //ne:不等于
        //查询name不等于蓝猫的数据
        QueryWrapper ne = queryWrapper.ne("name", "蓝猫");
        //name不等于蓝猫的数据有多条，所以使用list
        List list = animalService.list(ne);
        System.out.println(list);
    }

[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

（2）gt、ge、lt、le

gt：大于，ge：大于等

@Test
    void contextGt() {
        QueryWrapper queryWrapper = new QueryWrapper<>();
        //gt:大于  查询年龄age大于4的数据
        QueryWrapper gt = queryWrapper.gt("age", 5);
        List list1 = animalService.list(gt);
        System.out.println(list1);

        System.out.println("===============================");

        //ge:大于等于  查询年龄大于等于5的数据
        QueryWrapper ge = queryWrapper.ge("age", 6);
        List list2 = animalService.list(ge);
        System.out.println(list2);
    }

[Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]
===============================
[Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

lt：小于，le：小于等于

@Test
    void contextLt() {
        //第一种写法  lt:小于  查询年龄小于6的数据
        QueryWrapper queryWrapper = new QueryWrapper<>();
        QueryWrapper lt = queryWrapper.lt("age", 6);
        List list3 = animalService.list(lt);
        System.out.println(list3);
        //第二种写法
        List list4 = animalService.list(new LambdaQueryWrapper().lt(Animal::getAge, 6));
        System.out.println(list4);

        System.out.println("=======================");

        //第一种写法  le：小于等于   查询年龄小于等于5的数据
        QueryWrapper queryWrapper1 = new QueryWrapper<>();
        QueryWrapper le = queryWrapper1.le("age",5);
        List list5 = animalService.list(le);
        System.out.println(list5);
        //第二种写法
        List list6 = animalService.list(new LambdaQueryWrapper().le(Animal::getAge,5));
        System.out.println(list6);
    }

[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12)]
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12)]
=======================
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12)]
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12)]

（3）between、notbetween

between：在值1和值2之间，notbetween：不在值1和值2之间

    @Test
    void contextBetween(){
        //between：在值1和值2之间.   查询年龄为5到7之间的数据
        List list7 = animalService.list(new LambdaQueryWrapper().between(Animal::getAge,5,7));
        System.out.println(list7);
        System.out.println("================");
        //notbetween：不在值1和值2之间
        List list8 = animalService.list(new LambdaQueryWrapper().notBetween(Animal::getAge,2,8));
        System.out.println(list8);
    }

[Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16)]
================
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02)]

（4）like、notLike、likeLeft、likeRight

like：’%值%’，notLike：’%值%’

    @Test
    void contextLike(){
        //like：%值%  sql中的模糊查询  查询名字中带有犬的数据
        List list9 = animalService.list(new LambdaQueryWrapper().like(Animal::getName,"犬"));
        System.out.println(list9);

        System.out.println("=============================");

        //notLike：%值%  查询名字不带有猫的数据
        List list10 = animalService.list(new LambdaQueryWrapper().notLike(Animal::getName,"猫"));
        System.out.println(list10);
    }

[Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14)]
=============================
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14)]

likeLeft：’%值’，likeRight：'值%'

    @Test
    void contextLeftRight(){
        //likeLeft：%值  左边数据模糊，右边为"虎".  查询name（动物名称）中最后一个为"虎"的数据
        List list11 = animalService.list(new LambdaQueryWrapper().likeLeft(Animal::getName,"虎"));
        System.out.println(list11);

        System.out.println("===========================");

        //likeRight：值%  左边为"大"，右边数据模糊.  查询名字第一个为"大"的数据
        List list12 = animalService.list(new LambdaQueryWrapper().likeRight(Animal::getName,"大"));
        System.out.println(list12);
    }

[Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27)]
===========================
[Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

（5）isNull、isNotNull

isNull：字段IS NULL（空），isNotNull：字段IS NOT NULL（不为空）

    @Test
    void contextNull(){
        //isNull：为空  查询alias（动物别名）为空的数据
        List list13 = animalService.list(new LambdaQueryWrapper().isNull(Animal::getAlias));
        System.out.println(list13);

        System.out.println("=============================");

        //isNotNull：不为空  查询alias（动物别名）不为空的数据
        List list14 = animalService.list(new LambdaQueryWrapper().isNotNull(Animal::getAlias));
        System.out.println(list14);
    }

[]
=============================
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

（6）in、notIn

in：指定查询的值，notIn：不介于指定的值；in：字段 IN (v0, v1, …)，notIn：字段 NOT IN (value.get(0), value.get(1), …)

    @Test
    void contextIn(){
        //in：指定查询的值  查询age（年龄）为3,4的数据
        List list15 = animalService.list(new LambdaQueryWrapper().in(Animal::getAge,3,4));
        System.out.println(list15);

        System.out.println("===========================");

        //notNot：不介于指定的值  查询age（年龄）不为1,2,3,4,5,6的数据
        List list16 = animalService.list(new LambdaQueryWrapper().notIn(Animal::getAge,1,2,3,4,5,6));
        System.out.println(list16);
    }

[Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09)]
===========================
[Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

（7）inSql、notInSql

inSql：字段 IN ( sql语句 )，notInSql：字段 NOT IN ( sql语句 )

    @Test
    void contextInSql(){
        //inSql：字段In （sql语句）  通过name查询age < 2 的数据
        List list17 = animalService.list(new LambdaQueryWrapper().inSql(Animal::getName,"select name from animal where age < 2"));
        System.out.println(list17);

        System.out.println("===========================");

        //notInSql：字段notIn  （sql语句）  通过那么查询age > 7 的数据
        List list18 = animalService.list(new LambdaQueryWrapper().notInSql(Animal::getName,"select name from animal where age < 7"));
        System.out.println(list18);
    }

[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02)]
===========================
[Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

（8）or、and

or：拼接OR，AND嵌套

注意事项：

主动调用or表示紧接着下一个方法不是用and连接！（不调用or则默认为使用and连接）

    @Test
    void contextOrAnd(){
        //or：或  查询name（动物名称）等于狮子或者age（年龄）小于等于2的数据
        List list19 = animalService.list(new LambdaQueryWrapper().eq(Animal::getName,"狮子").or().le(Animal::getAge,2));
        System.out.println(list19);

        System.out.println("=======================");

        //and：并且  查询anme（动物名称）最后一个为"犬"并且age（年龄）大于5的数据
        List list20 = animalService.list(new LambdaQueryWrapper().likeLeft(Animal::getName,"犬").gt(Animal::getAge,5));
        System.out.println(list20);
    }

[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09)]
=======================
[Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14)]

不使用and默认就是and

（9）exists、notExists

exists：拼接EXISTS（sql语句），notExists：拼接NOT EXISTS（sql语句）

    @Test
    void contextExists(){
        //exists：拼接  查询age（年龄）大于6 的数据
        List list21 = animalService.list(new LambdaQueryWrapper().exists("select name,alias,description from animal where age > 6"));
        System.out.println(list21);
    }

查询结果显示数据库版本有问题说明不支持该版本的MySQL.导致数据结果不对.

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
2021-12-01 18:00:53.425  INFO 20440 --- [           main] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} inited
[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]

（10）orderByAsc、orderByDesc

orderByAsc：排序：ORDER BY 字段, … ASC，orderByDesc：排序：ORDER BY 字段, … DESC

    @Test
    void contextOrderByAsc(){

        //orderByAsc：升序  通过age（年龄）升序排序
        List list22 = animalService.list(new LambdaQueryWrapper().orderByAsc(Animal::getAge));
        System.out.println(list22);

        System.out.println("=============================");

        //orderByDesc：降序  通过age（年龄）降序排序
        List list23 = animalService.list(new LambdaQueryWrapper().orderByDesc(Animal::getAge));
        System.out.println(list23);
    }

[Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19)]
=============================
[Animal(name=大熊猫, age=8, alias=国宝, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:19), Animal(name=蓝猫, age=7, alias=猫, description=家养, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:16), Animal(name=西伯利亚雪橇犬, age=6, alias=二哈, description=富足家庭中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:14), Animal(name=边境牧羊犬, age=5, alias=边牧, description=家中, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:12), Animal(name=狮子, age=4, alias=辛巴, description=影视, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:09), Animal(name=孔雀, age=3, alias=白孔雀, description=北京动物园, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=东北虎, age=2, alias=大脑虎, description=东北地区, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 11:48:27), Animal(name=西伯利亚猩猩, age=1, alias=黑猩猩, description=西伯利亚, inputtime=2021-10-27 15:30:50, updatetime=2021-12-01 15:25:02)]

MybatisPlus条件构造器wrapper方法的使用

二、QueryWrapper的方法

三、目录结构

（1）目录

2、Mapper接口层
package com.wrapper.mapper; import com.baomidou.mybatisplus.core.mapper.baseMapper; import com.wrapper.entity.Animal; import org.apache.ibatis.annotations.Mapper; @Mapper public interface AnimalMapper extends baseMapper { }

4、IAnimalService服务类
package com.wrapper.service; import com.baomidou.mybatisplus.extension.service.IService; import com.wrapper.entity.Animal; public interface IAnimalService extends IService { }

四、实例

Java相关栏目本月热门文章

MybatisPlus条件构造器wrapper方法的使用

二、QueryWrapper的方法

三、目录结构

（1）目录

2、Mapper接口层 package com.wrapper.mapper; import com.baomidou.mybatisplus.core.mapper.baseMapper; import com.wrapper.entity.Animal; import org.apache.ibatis.annotations.Mapper; @Mapper public interface AnimalMapper extends baseMapper { }

4、IAnimalService服务类 package com.wrapper.service; import com.baomidou.mybatisplus.extension.service.IService; import com.wrapper.entity.Animal; public interface IAnimalService extends IService { }

四、实例

Java相关栏目本月热门文章

2、Mapper接口层
package com.wrapper.mapper; import com.baomidou.mybatisplus.core.mapper.baseMapper; import com.wrapper.entity.Animal; import org.apache.ibatis.annotations.Mapper; @Mapper public interface AnimalMapper extends baseMapper { }

4、IAnimalService服务类
package com.wrapper.service; import com.baomidou.mybatisplus.extension.service.IService; import com.wrapper.entity.Animal; public interface IAnimalService extends IService { }