SpringBoot学习笔记(二)——整合Mybatis并实现用户查询

	org.mybatis.spring.boot
	mybatis-spring-boot-starter
	2.2.2


	mysql
	mysql-connector-java

# application-dev.properties
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/login?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root123
mybatis.mapper-locations:classpath:mapping/*.xml

package com.galago.demo_web.entry;

public class User {
    private Integer id;
    private String username;
    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}

package com.galago.demo_web.mapper;

import com.galago.demo_web.entry.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

@Mapper // 该注解可以帮助mybatis找到mapper接口，生成动态代理类。或者在启动文件配置@MapperScan
public interface UserMapper {

    User getUser(Integer id);

}

 
    
        
        
        
        
    

    
        select * from t_user where id = #{id}
    

注意：resources/mapping目录下的xml文件名需和Mapper接口名一致

4.4 编写UserService接口——Service层

package com.galago.demo_web.services;

import com.galago.demo_web.entry.User;
import com.galago.demo_web.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

public interface UserService {
    User getUser(Integer id);
}

4.5 编写UserServiceImpl实现类——service层

package com.galago.demo_web.impl;

import com.galago.demo_web.entry.User;
import com.galago.demo_web.mapper.UserMapper;
import com.galago.demo_web.services.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserserviceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    public User getUser(Integer id) {
        return userMapper.getUser(id);
    }
}

4.6 编写UserController类——Controller层

package com.galago.demo_web.controller;

import com.galago.demo_web.entry.User;
import com.galago.demo_web.impl.UserserviceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@RequestMapping("/user") // 此处表示该类中所有相应请求的方法都是以该地址作为父地址, /user/selectone
@Controller
public class UserController {

    @Autowired
    UserserviceImpl userserviceImpl;

    @RequestMapping("/selectone")
    @ResponseBody // 返回值转为json数据
    public User getUser(Integer id) {
        System.out.println(id);
        return  userserviceImpl.getUser(id);
    }
}