Spring入门Blog[五、Spring容器组建注解@Component和Resouces实现完全注解配置]

@Resource和@Component实现零XML配置1、@Resource的注解：@Resource是J2EE的注解。意思是说在容器里面找相应的资源。也可以通过name属性指定它name的资源。可以注解到field或者setter上面public class UserAction {private UserService userService;@Resource(name="userService")public void setUserService(UserService userService) {this.userService = userService;}public void addUser(){userService.HelloWorld();}}2、@Component@Component和<context:component-scan base-package="com.spring"></context:component-scan>配合实现无XML配置，只通过注解配置及可将类放入资源容器中。案例解析：1、xml文件：配置容器资源扫描的包<?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-2.5.xsd           http://www.springframework.org/schema/context           http://www.springframework.org/schema/context/spring-context-2.5.xsd">         <context:annotation-config/>    <!-- 配置容器资源扫描的包 -->   <context:component-scan base-package="com.spring"></context:component-scan></beans>2、Java文件：标注资源的注解@Component。括号里面指定的是存入容器的name属性为userService那么将来我们拿的时候则getBean(“userService”)即可。如果我们不指定userService它默认存入容器bean的key为userServiceImpl这样就可以得到一个装有UserServiceImpl对象的容器package com.spring.service;import org.springframework.stereotype.Component;import com.spring.dao.UserDao;@Component("userService")public class UserServiceImpl implements UserService{private UserDao userDao;public void init(){System.out.println("init");}public void destory(){System.out.println("destory");}public UserDao getUserDao() {return userDao;}public void setUserDao(UserDao userDao) {this.userDao = userDao;}public void HelloWorld(){System.out.println("helloworld");}}通过@Resource将资源注入进来因为上文已经配置了容器里面的资源。所以我这里将资源通过@Resource注解将资源注入到相关的属性。请看代码：@Component("userAction")public class UserAction {private UserService userService;//它会将beans的xml文件配置加入进去//也可以使用name属性指定byName的指定@Resource(name="userService")public void setUserService(UserService userService) {this.userService = userService;}public void addUser(){userService.HelloWorld();}}测试实现：通过上文配置的userAction案例来得到这个对象然后调用它里面的方法，因为上文通过了@ Component注解将UserAction的对象配置到了容器里面。所以获得容器之后就可以用这种方法getbean即可@Testpublic void test01(){BeanFactory applicationContext = new ClassPathXmlApplicationContext("beans.xml");UserAction user = (UserAction) applicationContext.getBean("userAction");user.addUser();}@Scope和@PostConstruct、@PreDestroy很简单就相当于前面讲到的作用于和initmethod和destorymethod请看下面代码。不再多说：@Scope("Singleton")@Component("userService")public class UserServiceImpl implements UserService{private UserDao userDao;@PostConstructpublic void init(){System.out.println("init");}@PreDestroypublic void destory(){System.out.println("destory");}public UserDao getUserDao() {return userDao;}public void setUserDao(UserDao userDao) {this.userDao = userDao;}public void HelloWorld(){System.out.println("helloworld");}}