Spring中常用注解

@Service用于标注业务层组件

@Controller用于标注控制层组件（如struts中的action）

@Repository用于标注数据访问组件，即DAO组件

@Component泛指组件，当组件不好归类的时候，我们可以使用这个注解进行标注

如下是一个测试例子：

applicationContext.xml

<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/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
	<!-- <context:annotation-config /> -->
	<context:component-scan base-package="com.zzt.test" />
</beans>

IUserService.java

package com.zzt.test;

public interface IUserService {
	public void service();
}

UserServiceImpl.java

package com.zzt.test;

import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements IUserService {

	@Override
	public void service() {
		System.out.println("service ...");
	}

}

Person.java

package com.zzt.test;


public interface Person {
	void testPerson();
}

Man.java

package com.zzt.test;

import org.springframework.stereotype.Component;


@Component//("man")
public class Man implements Person {

	@Override
	public void testPerson() {
		System.out.println("===========man===========");
		
	}

}

Woman.java

package com.zzt.test;

import org.springframework.stereotype.Component;

@Component//("woman")
public class Woman implements Person {

	@Override
	public void testPerson() {
		System.out.println("===========woman=========");
		
	}

}

用于测试的类：TestAction.java

package com.zzt.test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;

@Controller
public class TestAction {

	@Autowired
	public IUserService userService;

	@Autowired
	@Qualifier("woman")
	private Person person;

	public void test() {
		userService.service();
		person.testPerson();
	}

}

程序入口：Demo.java

package com.zzt.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Demo {

	public static void main(String[] args) throws InterruptedException {

		ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

		TestAction action = (TestAction) context.getBean("testAction");
		action.test();
	}
}

getBean的默认名称是类名（头字母小写），如果想自定义，可以@Service(“aaaaa”)这样来指定，这种bean默认是单例的，如果想改变，可以使用 @Service(“beanName”) @Scope(“prototype”)来改变。可以使用以下方式指定初始化方法和销毁方法（方法名任意）：

@PostConstruct public void init() {

}

@PreDestroy public void destory() {

}

关于更多注解的使用，参考：http://www.iteye.com/topic/295348

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