1. HelloWorld的例子改成用注解来实现

HelloWorld类，采用@Component注解

package com.spring.annotation;
import org.springframework.stereotype.Component;
@Component
public class HelloWorld {
   public String getHello() {
        return "Hello World";
   }
}

HelloWorldApp类，采用@ComponentScan注解

package com.spring.annotation;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;

@ComponentScan
public class HelloApp {

public static void main(String[] args) {
  ApplicationContext context = new AnnotationConfigApplicationContext(HelloApp.class);
  HelloWorld  helloWorld = context.getBean(HelloWorld.class);
  System.out.println(helloWorld.getHello());
    }
}

运行结果

image.png

2、Student和Phone的例子改成用注解的方法实现

Lombok插件的使用
打开Settings,选择Plugins，搜索Lombok，安装，重启IDEA
添加依赖

<dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.16.18</version>
      <scope>provided</scope>
  </dependency>

Phone类

 package com.spring.annotation;
import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

/**
* 采用注解和Lombok开发的Phone类
*/
@Component
@Data
public class Phone {
@Value("iPhoneX")
private String brand;

@Value("6666.66")
private double price;
}

Student类

package com.spring.annotation;

import lombok.Data;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
@Data
public class Student {
@Value("Tom")
private  String name;

@Value("20")
private int age;
//使用@Autowired注入一个Phone类型的bean
@Autowired
private Phone phone;
}

StudentApp类

package com.spring.annotation;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
@ComponentScan
public class StudentApp {
public static void main(String[] args) {
  ApplicationContext context=new AnnotationConfigApplicationContext(StudentApp.class);
  Student student=context.getBean(Student.class);
  System.out.println(student);
     }
}