SprintBoot MyBatis 查数据数据返回 Object、Map、List、Map＜List＞小结

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SprintBoot MyBatis 查数据数据返回 Object、Map、List、Map＜List＞小结

2023-08-30 03:50| 来源: 网络整理| 查看: 265

前言：

SpringBoot + MyBatis 框架进行接口返回时，常常需要封装一下对象类似JSON数据结构的操作，案例通过常见web接口数据结构几种进行演示。

代码层级

--PackageName 包名

----test 目录

------controller 控制层：定义url，控制入参

------entity 对象层：这里指User对象的属性定义

------maaper 数据库语句定义层：sql数据的增删改查查询书写

------service 服务层：调用sql语句并进行一些逻辑判断处理

TestMyBatisController.java

package com.qabujiaban.benjamin.test.controller; /** * @Author: Benjamin * @Date: 2021/8/12 11:37 */ import com.qabujiaban.benjamin.test.entity.User; import com.qabujiaban.benjamin.test.service.TestMyBatisService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.HashMap; import java.util.List; import java.util.Map; /** 流程 1、controller 控制层，url定义的逻辑定义 2、maaper 原始sql语句 3、service 参数处理及分页原理 4、entity 对象属性 */ @RestController public class TestMyBatisController { @Autowired private TestMyBatisService testMyBatisService; @RequestMapping("/getUserId") public User getUserId(Integer id){ return testMyBatisService.getUserInfo(id); } @RequestMapping("/getAllUser") public List getAllUser(){ return testMyBatisService.getAllUser(); } @RequestMapping("/getAllUserPro") public Map getAllUserPro(){ Map result = new HashMap(); result.put("errorCode",0); result.put("errorMeg","成功"); result.put("AllUserInfo",testMyBatisService.getAllUser()); return result; } @RequestMapping("/getUserIdMap") public Map getUserIdMap(Integer id){ return testMyBatisService.getUserIdMap(id); } }

User.java

package com.qabujiaban.benjamin.test.entity; /** * @Author: Benjamin * @Date: 2021/8/12 11:41 */ public class User { public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getIp() { return ip; } public void setIp(String ip) { this.ip = ip; } public String getCreate_time() { return create_time; } public void setCreate_time(String create_time) { this.create_time = create_time; } private int id; private String username; private String password; private String ip; private String create_time; }

为了方便对比查看贴图表明User表中的数据

TestMyBatisMapper.java

package com.qabujiaban.benjamin.test.maaper; /** * @Author: Benjamin * @Date: 2021/8/12 11:37 */ import com.qabujiaban.benjamin.test.entity.User; import org.apache.ibatis.annotations.Mapper; import org.apache.ibatis.annotations.Param; import org.apache.ibatis.annotations.Select; import java.util.List; import java.util.Map; @Mapper public interface TestMyBatisMapper { @Select("select * from user where id = #{id}") User findUserId(@Param("id") Integer id); @Select("select * from user") List findAllUser(); @Select("select * from user where id = #{id}") Map findUserIdMap(@Param("id") Integer id); }

判空和未判空任选其一即可

TestMybatisService.java 未做判空处理

package com.qabujiaban.benjamin.test.service; import com.qabujiaban.benjamin.test.entity.User; import com.qabujiaban.benjamin.test.maaper.TestMyBatisMapper; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List; import java.util.Map; /** * @Author: Benjamin * @Date: 2021/8/12 11:37 */ @Service public class TestMyBatisService { @Autowired private TestMyBatisMapper testMyBatisMapper; public User getUserInfo(Integer id){ return testMyBatisMapper.findUserId(id); } public List getAllUser(){ return testMyBatisMapper.findAllUser(); } public Map getUserIdMap(Integer id){ return testMyBatisMapper.findUserIdMap(id); } }

TestMyBatisService.java 已做判空处理

package com.qabujiaban.benjamin.test.service; import com.qabujiaban.benjamin.test.entity.User; import com.qabujiaban.benjamin.test.maaper.TestMyBatisMapper; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; /** * @Author: Benjamin * @Date: 2021/8/12 11:37 */ @Service public class TestMyBatisService { @Autowired private TestMyBatisMapper testMyBatisMapper; public User getUserInfo(Integer id){ User user = testMyBatisMapper.findUserId(id); if(user == null){ return new User(); } return user; } public Map getUserIdMap(Integer id){ Map user = testMyBatisMapper.findUserIdMap(id); if(user == null){ return new HashMap(); } return user; } public List getAllUser(){ List user = testMyBatisMapper.findAllUser(); if(user == null){ return new ArrayList(); } return testMyBatisMapper.findAllUser(); } }

代码层级截图