01点睛Spring4.1-依赖注入

package com.wisely.di;

import org.springframework.stereotype.Service;

@Service//写为@Component,@Controller,@Repository效果相同,视具体情况使用
public class Demo1Service {

    public String sayHello(String word ){
        return "Hello "+word;
    }
}

package com.wisely.di;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class Demo2Service {
    @Autowired //注入Demo1Service,还可使用JavaEE的@Inject(JSR-330),@Resource(JSR-250)效果相同
    Demo1Service demo1Service;
    public String callDemo1SayHello(String word){
        return demo1Service.sayHello(word);
    }

}

package com.wisely.di;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;


public class Main {

    public static void main(String[] args) {
        //设定此包下的类被注册成spring的bean,包含@Configuration,@Component,@Service,@Repository,@Controller
        AnnotationConfigApplicationContext context =
                new AnnotationConfigApplicationContext("com.wisely.di");
        Demo2Service demo2Service = context.getBean(Demo2Service.class);
        System.out.println(demo2Service.callDemo1SayHello("World"));
        context.close();
    }

}