SpringBoot整合MyBatis

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>