spring_annotation_scan(Component)

spring自动
项目结构如下：
[img]http://dl2.iteye.com/upload/attachment/0095/2809/87a7ae0a-ca46-37f7-884f-63066f54e586.jpg[/img]

一。实体类（不重要）

public class User {
	private String username;
	private String password;
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}

}

二。自动扫描applicationContext.xml配置

<?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"
		xmlns:tx="http://www.springframework.org/schema/tx"
		xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
				http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd" >

	<context:annotation-config />
	<context:component-scan base-package="com.job"/>
</beans>

<context:component-scan base-package="com.job"/>配置扫描的包路径

三。服务类

@Scope("prototype")
@Component
public class UserService {

	private UserDAO userDAO;

	@PostConstruct //相当于xml中bean配置init-method方法，在初始化之前执行此方法
	public void init(){
		System.out.println("init");
	}
	public void add(User u){
		this.userDAO.save(u);
	}

	public UserDAO getUserDAO() {
		return userDAO;
	}
	@Resource(name="u")
	public void setUserDAO(@Qualifier("userDAOImpl")UserDAO userDAO) {
		this.userDAO = userDAO;
	}

	@PreDestroy //相当于xml中bean配置destroy-method方法，在初始化之后执此方法
	public void destory(){
		System.out.println("destory");
	}
}

@Component表示自动扫描时的服务组件（也可用@Service）
@Resource(name="u")表示自动注入组件名为"u"

@Scope("prototype")表示获得时新创建一个实例
@PostConstruct/@PreDestroy 表示实例创建和消毁时执行的方法
在applicationContext.xml配置方式如下：

	<bean id="userService" class="com.job.service.UserService" lazy-init="true" init-method="init" destroy-method="destroy" scope="prototype">
		<property name="userDAO" ref="userDAOImpl"></property>
	</bean>

四。服务类实现

@Component("u")
public class UserDAOImpl implements UserDAO{

	@Override
	public void save(User u) {
		System.out.println(u.getUsername()+"user---haha!");
	}
}

@Component("u")表示组件，也可用（@Repository("u")）

五。服务实现接口（不重要）

public interface UserDAO {
	public void save(User u);
}

六。测试

public class UserServiceTest {
	@Test
	public void test(){
		ApplicationContext ac =  new ClassPathXmlApplicationContext("applicationContext.xml");
		UserService service = (UserService)ac.getBean("userService");
		User u = new User();
		u.setUsername("me haha  ");
		service.add(u);

	}
}

七。测试结果

me haha user---haha!