spring 获取bean的几种方法

1. 实现BeanFactoryAware

   public class ServiceLocator implements BeanFactoryAware {
   
    	private static BeanFactory beanFactory;
    
    	@Override
    	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
    		ServiceLocator.beanFactory = beanFactory;
    	}
    
    	/**
    	 * 根据提供的bean名称得到相应的服务类
    	 * 
    	 * @param servName
    	 * bean名称
    	 */
    	public static Object getService(String servName) {
    		return beanFactory.getBean(servName);
    	}
    
    }
   

   spring配置文件

    <bean id="serviceLocator" class="com.taobao.appcenter.common.ServiceLocator" lazy-init="false"/>
   

2. 实现ApplicationContextAware

    public class SpringContextsUtil implements ApplicationContextAware {
    	
    	private static ApplicationContext applicationContext;    //Spring context   
    
    	@Override
    	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    		SpringContextsUtil.applicationContext = applicationContext;
    	}
    	
    	/**
    	  * @return ApplicationContext
    	  */
    	  public static ApplicationContext getApplicationContext() {
    	    return applicationContext;
    	  }
    	 
    	  /**
    	  * 获取对象  
    	  * @param name
    	  * @return Object 一个以所给名字注册的bean的实例
    	  * @throws BeansException
    	  */
    	  public static Object getBean(String name) throws BeansException {
    	    return applicationContext.getBean(name);
    	  }
    }
   

   spring xml配置文件

    <bean id="springContext" class="com.taobao.appcenter.common.SpringContext" lazy-init="false"/>
   

3. 通过servlet 或listener设置spring的ApplicationContext,以便后来引用,这个是针对web 工程的

    	public class SpringContext {
    	private static ApplicationContext applicationContext; // Spring应用上下文环境
    
    	public static void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    		SpringContext.applicationContext = applicationContext;
    	}
    
    	/**
    	 * @return ApplicationContext
    	 */
    	public static ApplicationContext getApplicationContext() {
    		return applicationContext;
    	}
    
    	public static Object getBean(String name) throws BeansException {
    		return applicationContext.getBean(name);
    	}
    }
   

   上面的SpingContext谁没实现任何接口的，不是回调的方式。而是在listener或者servlet中set进来

    public class SpringContextLoaderListener extends ContextLoaderListener {
    	
    	
    	public void contextInitialized(ServletContextEvent event){
    		super.contextInitialized(event);
    		SpringContext.setApplicationContext(WebApplicationContextUtils.getWebApplicationContext(event.getServletContext()));
    	}
    	
    	
    }
   

   替换web.xml文件的listener为上面的文件

    <listener>
    	<listener-class>com.taobao.appcenter.common.SpringContextLoaderListener</listener-class>
    </listener>
   

   servlet的代码如下

    public class SpringContextLoaderServlet extends ContextLoaderServlet {
     private ContextLoader contextLoader;
        public void init() throws ServletException {
            this.contextLoader = createContextLoader();
            SpringContext.setApplicationContext(this.contextLoader.initWebApplicationContext(getServletContext()));
        }
    }
   

   然后配置web.xml中的servlt和mapping即可。

4. 调用

   由于使用的都是静态函数,使用getBean(Stirng name)或者getService(String serviceName)就可以获得xml配置的业务自己bean。