接着上一节的课程继续学习

MesasageService 类

package hello;import org.springframework.stereotype.Component;
//注解的加入
@Component
public class MesasageService {public MesasageService() {super();System.out.println("MessageService...");}/*** 执行打印功能* @return 返回要打印的字符串*/public String getMessage(){return "Hello World";}
}

MessagePrinter类

package hello;import org.springframework.stereotype.Component;
//注解的加入
@Component
public class MessagePrinter {//无参构造方法的加入public MessagePrinter() {super();System.out.println("MessagePrinter...");}private MesasageService service;/** 简历和MessageService的关系* *///设置service的值public void setService(MesasageService service){this.service =service;}public void printMessage(){System.out.println(this.service.getMessage());}
}

ApplicationSpring类

package hello;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;//加入扫描
@ComponentScan
public class ApplicationSpring {public static void main(String[] args){System.out.println("appliaction....");//初始化springApplicationContext context =new AnnotationConfigApplicationContext(ApplicationSpring.class);//获取messagePrinter对象MessagePrinter printer=context.getBean(MessagePrinter.class);//获取messafeService对象MesasageService service=context.getBean(MesasageService.class);System.out.println(printer);System.out.println(service);printer.setService(service);//打印消息printer.printMessage();}
}

运行结果

appliaction....
10月 27, 2019 6:30:54 下午 org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@3d012ddd: startup date [Sun Oct 27 18:30:54 CST 2019]; root of context hierarchy
MessageService...
MessagePrinter...
hello.MessagePrinter@10e92f8f
hello.MesasageService@7ce3cb8e
Hello World