练习

在 Spring 项⽬中，通过 main ⽅法获取到 Controller 类，调⽤ Controller ⾥⾯通过注⼊的⽅式调⽤ Service 类，Service 再通过注⼊的⽅式获取到 Repository 类，Repository 类⾥⾯有⼀个⽅法构建⼀个 User 对象，返回给 main ⽅法。Repository ⽆需连接数据库，使⽤伪代码即可。

User类

package com.java.demo.model;public class User {private int id;private String name;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic String toString() {return "User{" +"id=" + id +", name='" + name + '\'' +'}';}
}

UserController类

package com.java.demo.controller;import com.java.demo.model.User;
import com.java.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;@Controller
public class UserController {@Autowiredprivate UserService userService;public User getUser() {return userService.getUser();}
}

UserRepository类

package com.java.demo.repository;import com.java.demo.model.User;
import org.springframework.stereotype.Repository;@Repository
public class UserRepository {public User getUser() {// 伪代码User user = new User();user.setId(1);user.setName("张三");return user;}
}

UserService类

package com.java.demo.service;import com.java.demo.model.User;
import com.java.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class UserService {@Autowiredprivate UserRepository userRepository;public User getUser() {return userRepository.getUser();}
}

App类

package com.java.demo;import com.java.demo.controller.UserController;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {public static void main(String[] args) {ApplicationContext context =new ClassPathXmlApplicationContext("spring-config.xml");UserController userController = context.getBean("userController", UserController.class);System.out.println(userController.getUser());}
}