spring boot集成mybatis-plus——条件构造器QueryWrapper常用方法

绝地灬酷狼 2023-09-29 18:49 9阅读 0赞

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package org.example.controller;
    
    import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
    import org.example.Entity.MyUser;
    import org.example.mapper.UserMapper;
    import org.example.service.MyUserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.*;
    
    import java.util.Arrays;
    import java.util.List;
    
    @RestController
    public class MyUserController
    {
    
        @Autowired
        private MyUserService myUserService;
    
        @Autowired
        private UserMapper userMapper;
    
    
        /**
         * 查询所有用户信息
         * @return
         */
        @GetMapping(value = "/findAll")
        public List<MyUser> findAll()
        {
            // 查询所有用户信息
            List<MyUser> users = myUserService.findAll();
    
            for (MyUser user : users)
            {
                System.out.println(user.getId()+"  "+user.getName()+"  "+user.getAge());
            }
    
            return users;
        }
    
    
        /**
         * 增加一个用户
         * @return
         */
        @GetMapping(value = "/save")
        public int save()
        {
            MyUser user = new MyUser();
            user.setName("小文");
            user.setAge(21);
    
            int insert = myUserService.save(user);//如果没有设置id，那么会自动生成id
    
            System.out.println(insert);//受影响行数
    
            System.out.println(user);//id会自动回填
    
            return insert;
        }
    
    
        /**
         * 根据id修改用户信息
         * @return
         */
        @GetMapping(value = "/updateById")
        public int updateById()
        {
            MyUser user = new MyUser();
            user.setId(1014);
            user.setName("小文改");
            user.setAge(222);
    
            int insert = myUserService.update(user);
    
            System.out.println(insert);//受影响行数
    
    
            return insert;
        }
    
    
        /**
         * 根据用户名修改用户信息
         * @return
         */
        @GetMapping(value = "/updateByName")
        public int updateByIdName()
        {
    
            int insert = myUserService.updateByName();
    
            System.out.println(insert);//受影响行数
    
            return insert;
        }
    
        ///
    
        ///
    
        ///
    
        ///
    
    
        /**
         * 根据单个id查询数据
         * @return
         */
    
        @GetMapping(value = "/findById")
        public MyUser findById()
        {
    
            MyUser user = userMapper.selectById("1015");
    
            System.out.println(user);
    
            return user;
        }
    
    
        /**
         * 根据多个id查询数据
         * @return
         */
        @GetMapping(value = "/findByMoreId")
        public List<MyUser> findByMoreId()
        {
            List list1 = Arrays.asList(1014,1015);
            List<MyUser> list2 = userMapper.selectBatchIds(list1);
    
            System.out.println(list2);
    
            return list2;
        }
    
    
    
        /**
         * 以name作为条件查询数据
         * @return
         */
        @GetMapping(value = "/findByName")
        public List<MyUser> findByName()
        {
            //首先构造QueryWrapper来进行条件的添加
            QueryWrapper wrapper = new QueryWrapper();
            wrapper.eq("name","小文");
    
            List<MyUser> list = userMapper.selectList(wrapper);
    
            System.out.println(list);
    
            return list;
        }
    
    
        /**
         * 以between age 作为条件查询数据
         * @return
         */
        @GetMapping(value = "/findByBetweenAge")
        public List<MyUser> findByBetweenAge()
        {
            //首先构造QueryWrapper来进行条件的添加
            QueryWrapper wrapper = new QueryWrapper();
            wrapper.between("age","100","200");
    
            List<MyUser> list = userMapper.selectList(wrapper);
    
            System.out.println(list);
    
            return list;
        }
    
    }

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[1722c11dd1c4182b6b650fcfa35760c1.png]: https://img-blog.csdnimg.cn/img_convert/1722c11dd1c4182b6b650fcfa35760c1.png
[c94c0535f19f4144dc59f08c9353a7d0.png]: https://img-blog.csdnimg.cn/img_convert/c94c0535f19f4144dc59f08c9353a7d0.png
[ff0cec129b7555bef4bf29b79997d370.png]: https://img-blog.csdnimg.cn/img_convert/ff0cec129b7555bef4bf29b79997d370.png