携手创作，共同成长！这是我参与「掘金日新计划 · 8 月更文挑战」的第12天，点击查看活动详情
1、创建模块
1、创建SpringBoot模块
2、勾选Mysql Driver,Mybatis Framework
2、坐标导入
因为刚刚以及勾选了mybatis,mysql,所以他们已经添加到了pom.xml中，下面导入其他坐标。
- lombok 减少get、set方法的编写
- druid 数据库连接池
<!-- 数据库连接池 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.2.4</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
3、项目目录构建
4、编写代码
1、定义实体类（与数据库一一对应）
package com.example.mybatis.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data #lombok的注解减少getset方法
@AllArgsConstructor
@NoArgsConstructor
public class User {
private Integer id;
private String name;
private String password;
}
2、mapper
package com.example.mybatis.mapper;
import com.example.mybatis.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;
@Mapper // 告诉springboot这是一个mybatis的mapepr类
@Repository // 将userdao交由spring容齐管理
public interface UserMapper {
// 查询所有用户
public List<User> listUser();
}
3、service接口
package com.example.mybatis.service;
import com.example.mybatis.pojo.User;
import java.util.List;
public interface UserService {
// 查询所有用户
public List<User> listUser();
}
4、service接口的实现类serviceimpl
package com.example.mybatis.service.impl;
import com.example.mybatis.mapper.UserMapper;
import com.example.mybatis.pojo.User;
import com.example.mybatis.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service // 交由spring容齐管理
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
public List<User> listUser() {
return userMapper.listUser();
}
}
5、Controller
package com.example.mybatis.controller;
import com.example.mybatis.pojo.User;
import com.example.mybatis.service.UserService;
import com.example.mybatis.untils.JSONResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class UserController {
@Autowired
private UserService userService;
@GetMapping("/users")
public JSONResult test(){
return JSONResult.ok(userService.listUser());
}
}
6、工具类JSONResult
package com.example.mybatis.untils;
/**
*
* @Title: JSONResult.java
* @Description: 自定义响应数据结构
* 本类可提供给 H5/ios/安卓/公众号/小程序 使用
* 前端接受此类数据（json object)后，可自行根据业务去实现相关功能
* 200：表示成功
* 500：表示错误，错误信息在msg字段中
* 501：bean验证错误，不管多少个错误都以map形式返回
* 502：拦截器拦截到用户token出错
* 555：异常抛出信息
* 556: 用户qq校验异常
* 557: 校验用户是否在CAS登录，用户门票的校验
* @Copyright: Copyright (c) 2020
*/
public class JSONResult {
// 响应业务状态
private Integer status;
// 响应消息
private String msg;
// 响应中的数据
private Object data;
private String ok; // 不使用
public static JSONResult build(Integer status, String msg, Object data) {
return new JSONResult(status, msg, data);
}
public static JSONResult build(Integer status, String msg, Object data, String ok) {
return new JSONResult(status, msg, data, ok);
}
public static JSONResult ok(Object data) {
return new JSONResult(data);
}
public static JSONResult ok() {
return new JSONResult(null);
}
public static JSONResult errorMsg(String msg) {
return new JSONResult(500, msg, null);
}
public static JSONResult errorUserTicket(String msg) {
return new JSONResult(557, msg, null);
}
public static JSONResult errorMap(Object data) {
return new JSONResult(501, "error", data);
}
public static JSONResult errorTokenMsg(String msg) {
return new JSONResult(502, msg, null);
}
public static JSONResult errorException(String msg) {
return new JSONResult(555, msg, null);
}
public static JSONResult errorUserQQ(String msg) {
return new JSONResult(556, msg, null);
}
public JSONResult() {
}
public JSONResult(Integer status, String msg, Object data) {
this.status = status;
this.msg = msg;
this.data = data;
}
public JSONResult(Integer status, String msg, Object data, String ok) {
this.status = status;
this.msg = msg;
this.data = data;
this.ok = ok;
}
public JSONResult(Object data) {
this.status = 200;
this.msg = "OK";
this.data = data;
}
public Boolean isOK() {
return this.status == 200;
}
public Integer getStatus() {
return status;
}
public void setStatus(Integer status) {
this.status = status;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
public String getOk() {
return ok;
}
public void setOk(String ok) {
this.ok = ok;
}
}
7、配置文件
server:
port: 8080
# 数据库数据源
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource # 数据源类型
username: root
password: xmpkj
url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT
driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
mapper-locations: classpath:/mapper/*.xml # xml文件
8、mapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mybatis.mapper.UserMapper">
<select id="listUser" resultType="com.example.mybatis.pojo.User">
select *from user
</select>
</mapper>
5、测试
运行项目，打开Postman或者Apifox访问
localhost:8080/users
成功从数据库查到信息
