IDEA 中 SpringBoot2 整合 Mybatis 實例 (Java8 + Maven + MySQL8)

記錄在 IDEA 中使用SpringBoot2 整合 Mybatis的實例，環境：Java8 + Maven + MySQL8。

1. 添加依賴

添加 MyBatis 依賴，MySQL 連接依賴,，數據庫用的MySQL8。

    <!-- MyBatis 依賴 -->
    <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>2.0.0</version>
    </dependency>

    <!-- MySQL 連接依賴 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>

2. 創建數據庫的 SQL語句

創建數據庫的 SQL語句如下所示：注意 ID 是自增的，而且是主鍵。

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `name` varchar(255) DEFAULT NULL,
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

數據庫 User 表結構：

3. 工程實例

項目的結構如圖所示：有些用不到，紅框中的本工程實例使用到的。

實體類 User.java :

package com.syrdbt.springbootstudy01.entity;

public class User {
    private String ID;
    private String name;

    public String getID() {
        return ID;
    }

    public void setID(String ID) {
        this.ID = ID;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "User{" +
                "ID='" + ID + '\'' +
                ", name='" + name + '\'' +
                '}';
    }
}

UserMapper.java ，Mapper類，相當於 DAO 層。

package com.syrdbt.springbootstudy01.mapper;

import com.syrdbt.springbootstudy01.entity.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

public interface UserMapper {
    @Select("SELECT * FROM USER WHERE NAME = #{name}")
    User getUser(@Param("name") String name);
    @Insert("INSERT INTO USER(NAME) VALUES(#{name})")
    int insert(@Param("name") String name);
}

UserService.java：

package com.syrdbt.springbootstudy01.services;

import com.syrdbt.springbootstudy01.entity.User;

public interface UserService {
    public User getUser(String name);

    public void insertUser(String name);
}

UserServiceImpl.java，Service 層調用 DAO 層。

package com.syrdbt.springbootstudy01.services.impl;

import com.syrdbt.springbootstudy01.entity.User;
import com.syrdbt.springbootstudy01.mapper.UserMapper;
import com.syrdbt.springbootstudy01.services.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service
public class UserServiceImpl implements UserService {
    @Resource
    UserMapper userMapper;

    @Override
    public User getUser(String name) {
        return userMapper.getUser(name);
    }

    @Override
    public void insertUser(String name) {
        userMapper.insert(name);
    }
}

TestMybatisController.java，控制器。

package com.syrdbt.springbootstudy01.controller.testMybatis;

import com.syrdbt.springbootstudy01.entity.User;
import com.syrdbt.springbootstudy01.services.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@EnableAutoConfiguration
@RestController
public class TestMybatisController {

    @Resource
    UserService userService;

    @RequestMapping("/insertUser")
    public String insertUser(@RequestParam(value = "name") String name) {
        System.out.println(name);
        userService.insertUser(name);
        return userService.getUser(name).getID();
    }

    @RequestMapping("/getUser")
    public String getUser(@RequestParam(value = "name") String name) {
        return userService.getUser(name).toString();
    }
}

SpringbootStudy01Application.java，啓動類。

掃描 Mapper使用 @MapperScan("com.syrdbt.springbootstudy01.mapper") 。

package com.syrdbt.springbootstudy01;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;

// 啓動類上加上@SpringBootApplication註解,當前包下或者子包下所有的類都可以掃到
@SpringBootApplication
// @EnableAsync 開啓異步調用
//@EnableAsync
// 掃描 Mapper
@MapperScan("com.syrdbt.springbootstudy01.mapper")
public class SpringbootStudy01Application {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootStudy01Application.class, args);
    }
}

application.properties ，數據庫配置文件，記得修改用戶名和密碼。

spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=password
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver