SpringBoot整合Mybatis（注解方式）-蒲公英云

SpringBoot整合Mybatis（注解方式）

SpringBoot整合Mybatis通常有两种方式，一种是以xml映射文件的，一种是以注解的方式实现的，这里主要是以注解的方式来实现

项目目录结构如下：

src
----main
--------java
------------com.example.app
----------------controller //控制器
--------------------UserController.java
----------------entity    //实体类
--------------------User.java
----------------mapper    //映射接口
--------------------UserRepository.java
----------------service   //业务
--------------------UserService.java
----resource
--------application.properties

首先先建一个表

CREATE TABLE `stus` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) DEFAULT NULL,
  `password` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=42 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

然后随便插几条数据即可

application.properties配置如下：

#端口配置
server.port = 8080 
#数据库配置
spring.datasource.url = jdbc:mysql://localhost:3306/数据库名?useSSL=false
#用户名
spring.datasource.username = 
#密码
spring.datasource.password = 
#驱动
spring.datasource.driver-class-name = com.mysql.jdbc.Driver

还是和以往一样先建一个实体类（User.java）

package com.example.app.entity;
/** * @author Woo_home * @create by 2019/10/4 */
public class User { 
    private int id;
    private String username;
    private String password;
    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;
    }
    @Override
    public String toString() { 
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

接着写一个mapper接口（UserRepository .java）

package com.example.app.mapper;
import com.example.app.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.springframework.stereotype.Repository;
import java.util.List;
/** * @author Woo_home * @create by 2019/10/4 */
@Mapper
public interface UserRepository { 
    @Select("select * from stus")
    List<User> getAllUser(); //查询所有用户
}

接着就是业务的编写

package com.example.app.service;
import com.example.app.entity.User;
import com.example.app.mapper.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
/** * @author Woo_home * @create by 2019/10/4 */
@Service
public class UserService { 
    @Autowired
    private UserRepository userRepository;
    public List<User> getAllUser(){ 
        return userRepository.getAllUser();
    }
}

控制器代码（UserController.java）

package com.example.app.controller;
import com.example.app.entity.User;
import com.example.app.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Repository;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.annotation.Resource;
import java.util.List;
/** * @author Woo_home * @create by 2019/10/4 */
@Controller
public class UserController { 
    @Autowired
    private UserService userService;
    @RequestMapping("/userList")
    @ResponseBody
    public List<User> userList(){ 
        return userService.getAllUser();
    }
}

启动类
@MapperScan是在插件包中定义的注解，该注解的参数是一个包名字符串，只要在@MapperScan中配置需要扫描的Mybatis接口的包路径，Spring就会自动扫描包下面的java接口，把这些类注册为Spring的bean

package com.example.app;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.example.app.mapper")
public class AppApplication { 
    public static void main(String[] args) { 
        SpringApplication.run(AppApplication.class, args);
    }
}