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  • mybatisplus----条件查询wrapper的基本操作

    直接上代码:

    package com.hui;
    
    import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
    import com.hui.mapper.UserMapper;
    import com.hui.pojo.User;
    import org.junit.jupiter.api.Test;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    
    import java.util.List;
    import java.util.Map;
    
    @SpringBootTest
    public class WrapperTest {
        @Autowired
        UserMapper userMapper;
    //下面这是条件查询
        //wrapper对象其实就是封装了一个条件,然后语句根据这个条件去执行
    
        @Test
        void testWrapper1() {
            QueryWrapper<User> wrapper = new QueryWrapper<>();
            wrapper.isNotNull("age")
                    .isNotNull("id")
                    .eq("age", 20);
    
            userMapper.selectList(wrapper).forEach(System.out::println);
        }
    
    
        @Test
        void testWrapper2() {
            QueryWrapper<User> wrapper = new QueryWrapper<>();
            wrapper.eq("name", "瓜瓜");
            System.out.println(userMapper.selectOne(wrapper));
        }
    
        @Test
        void testWrapper3() {
            QueryWrapper<User> wrapper = new QueryWrapper<>();
            wrapper.eq("name", "本杰明");
    
            Integer integer = userMapper.selectCount(wrapper);
            System.out.println(integer);
    
    
        }
    
    
        @Test
        void testWrapper4() {
            QueryWrapper<User> wrapper = new QueryWrapper<>();
            wrapper.likeRight("email", "t");
    
            List<Map<String, Object>> maps = userMapper.selectMaps(wrapper);
            maps.forEach(System.out::println);
    
    
        }
    
        @Test
        void testWrapper5() {
    
            QueryWrapper<User> wrapper = new QueryWrapper<>();
            wrapper.inSql("id", "select id from user where id=2");
            List<Object> objects = userMapper.selectObjs(wrapper);
            objects.forEach(System.out::println);
    
    
        }
    
        @Test
        void testWrapper6() {
            QueryWrapper<User> wrapper = new QueryWrapper<>();
            wrapper.orderByDesc("id");
            List<User> users = userMapper.selectList(wrapper);
            users.forEach(System.out::println);
        }
    }
    迎风少年
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  • 原文地址:https://www.cnblogs.com/ZYH-coder0927/p/13970678.html
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