[大数据]mybatis-plus条件构造器

QueryWrapper类和 UpdateWrapper类，可以实现多条件复杂查询

package com.zhmsky.mybatisplus_02;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.zhmsky.mybatisplus_02.pojo.User;
import com.zhmsky.mybatisplus_02.service.UserService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

/**
 * @author zhmsky
 * @date 2021/12/1 11:12
 * @description 复杂条件查询  使用 Wrapper
 */
@SpringBootTest
public class WrapperTest {

    @Autowired
    private UserService userService;

    @Test
    void contextLoads() {
    }

    //查询邮箱不为空且name不为空 ，年命令大于20的用户
    @Test
    void selectUser1(){
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper.isNotNull("email").isNotNull("name").ge("age",20);
        List<User> userList = userService.list(wrapper);
        for (User user : userList) {
            System.out.println(user.toString());
        }
    }

    //只查询一个用户使用getOne
    @Test
    void selectUser2(){
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper.eq("name","嘻嘻嘻").ge("age",20);
        User user = userService.getOne(wrapper);
        System.out.println(user.toString());
    }

    //查询年龄在18-23的用户
    @Test
    void selectUser3(){
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper.between("age",18,23);   //区间
        List<User> userList = userService.list(wrapper);
        userList.forEach(System.out::println);
    }

    //模糊查询（查询名字不包含a的和邮箱以t开头的用户）
    @Test
    void selectUser4(){
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper.notLike("name","a").likeRight("email","test");  // %在左边，也就是test%
        List<User> userList = userService.list(wrapper);
        for (User user : userList) {
            System.out.println(user.toString());
        }
    }

    //子查询
    @Test
    void selectUser5(){
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        //SELECT id,name,age,email,version,deleted,create_time,update_time FROM user WHERE deleted=0 AND (id IN (select id from user where id<3))
        wrapper.inSql("id","select id from user where id<3");
        List<User> userList = userService.list(wrapper);
        userList.forEach(System.out::println);

    }

    //降序排序
    @Test
    void selectUser6(){
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper.orderByDesc("age");
        List<User> userList = userService.list(wrapper);
        userList.forEach(System.out::println);
    }

}