Spring In Action-2.1-01-@Component注解

代码下载：http://download.csdn.net/download/poiuy1991719/9959474

//@Component注解会告诉Spring创建这个类的实例bean（注意，启动Component注解功能需要在xml里面配置，下面会将）
@Component

//接口
package soundsystem;

import org.springframework.stereotype.Component;

public interface CompactDisc {
	void play();
}

　　

//接口实现类
package soundsystem;

import org.springframework.stereotype.Component;

//@Component注解会告诉Spring创建这个类的实例bean（注意，启动Component注解功能需要在xml里面配置）
@Component
public class SgtPeppers implements CompactDisc {

	private String title="Pepper's Lonely";
	private String artist="The beatles";
	
	SgtPeppers(){
		System.out.println("SgtPeppers类实例化");
	}
	
	public void play() {
		System.out.println("Sgt Playing:title="+title+" artist="+artist);
	}

}

　　

扫描有两种方式：

一、java代码方式：

//配置类
package soundsystem;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

//ComponentScan：本类所在包的所有子包都会被扫描，并自动为其创建bean
@Configuration
@ComponentScan
public class CDPlayerSpringConfig {

}

　　

//测试类
package soundsystem;

import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)//Spring的Junit测试，会在测试开始时，创建Spring的应用上下文
@ContextConfiguration(classes=CDPlayerSpringConfig.class)//表明配置类
public class SpringTest1 {

	//自动装配
	@Autowired
	private SgtPeppers sp;
	
	@Test 
	public void instanceSpring(){
		sp.play();
	}
}

　　

二、xml配置方式：

package soundsystem;

import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringTest2 {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@Test 
	public void instanceSpring(){
		//将配置传过去，实例化容器
		ApplicationContext ctx = new ClassPathXmlApplicationContext("bean.xml");
		SgtPeppers sp = (SgtPeppers)ctx.getBean("sgtPeppers");
		sp.play();
	}
}

　　

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">
           
    <!-- 自动扫描配置 -->
    <context:component-scan base-package="soundsystem" />

</beans>