在Web中任意位置得到Spring ApplicationContext

Access the Spring-ApplicationContext from everywhere in your Application

-- from  http://blog.jdevelop.eu/2008/07/06/access-the-spring-applicationcontext-from-everywhere-in-your-application/

In this blog i will show you a short hint how you can access your Spring-ApplicationContext from everywhere in your Application.

Imagine you have an application (e.g. a web or swing-application) which you now want to be Spring-enabled. Ok you add the Spring libraries and the Configuration-file and create your Spring-beans. But there are still some old class-files which you can’t use in this way. These files still need access to the Spring-Honeypot where all the goodies exists and you don’t want to redesign your application.

First create the class “ApplicationContextProvider“. This class implements theApplicationContextAware. A bean which implements the ApplicationContextAware-interface and is deployed into the context, will be called back on creation of the bean, using the interface’s setApplicationContext(…) method, and provided with a reference to the context, which may be stored for later interaction with the context.

ApplicationContextProvider.java

 
    
    package 
     context;

 
    
    import 
     org.springframework.beans.BeansException;
 
    
    import 
     org.springframework.context.ApplicationContext;
 
    
    import 
     org.springframework.context.ApplicationContextAware;

 
    
    /**
 
    
     * This class provides an application-wide access to the
 
    
     * Spring ApplicationContext! The ApplicationContext is
 
    
     * injected in a static method of the class "AppContext".
 
    
     *
 
    
     * Use AppContext.getApplicationContext() to get access
 
    
     * to all Spring Beans.
 
    
     *
 
    
     * @author Siegfried Bolz
 
    
     */
 
    
    public 
      
    class 
     ApplicationContextProvider  
    implements 
     ApplicationContextAware {

 
   
          
    public 
      
    void 
     setApplicationContext(ApplicationContext ctx)  
    throws 
     BeansException {
 
   
              
    // Wiring the ApplicationContext into a static method
 
   
             AppContext.setApplicationContext(ctx);
 
   
         }
 
   
     }  
    // .EOF

This bean must be initialized in the Spring-Configuration file:

applicationContext.xml

 
    
    < 
    bean 
      
    id 
    = 
    "contextApplicationContextProvider" 
      
    class 
    = 
    "context.ApplicationContextProvider" 
    > 
    </ 
    bean 
    >

The key for success is located in the in the method “setApplicationContext(…)“, here we are wiring the injected ApplicationContext into the static method “public static void setApplicationContext(ApplicationContext applicationContext) of the class “AppContext“:

AppContext.java

 
    
    package 
     context;

 
    
    import 
     org.springframework.context.ApplicationContext;

 
    
    /**
 
    
     * This class provides application-wide access to the Spring ApplicationContext.
 
    
     * The ApplicationContext is injected by the class "ApplicationContextProvider".
 
    
     *
 
    
     * @author Siegfried Bolz
 
    
     */
 
    
    public 
      
    class 
     AppContext {

 
   
          
    private 
      
    static 
     ApplicationContext ctx;

 
   
          
    /**
 
    
         * Injected from the class "ApplicationContextProvider" which is automatically
 
    
         * loaded during Spring-Initialization.
 
    
         */
 
   
          
    public 
      
    static 
      
    void 
     setApplicationContext(ApplicationContext applicationContext) {
 
   
             ctx = applicationContext;
 
   
         }

 
   
          
    /**
 
    
         * Get access to the Spring ApplicationContext from everywhere in your Application.
 
    
         *
 
    
         * @return
 
    
         */
 
   
          
    public 
      
    static 
     ApplicationContext getApplicationContext() {
 
   
              
    return 
     ctx;
 
   
         }
 
   
     }  
    // .EOF

Now you have access from all class-files to the Spring-ApplicationContext in your application, if you call the static method:

Poorfile.java

 
    
    ApplicationContext ctx = AppContext.getApplicationContext();
 
   
     Honeypotbean honey = (HoneyPotBean) ctx.getBean( 
    "honey" 
    );

Do you have any improvements? Please drop a comment below.