/** 
   * <p>Initialize this servlet. Most of the processing has been factored into 
   * support methods so that you can overrideparticular functionality at a 
   * fairly granular level.</p> 
   * 
   * @exception ServletException if we cannotconfigure ourselves correctly 
   */ 
  publicvoidinit() throwsServletException { 
  
    // Wraps the entire initialization in a try/catch tobetter handle 
    // unexpected exceptions and errors to provide better feedback 
    // to the developer 
    try { 
      initInternal(); 
      initOther(); 
      initServlet(); 
   
      getServletContext().setAttribute(Globals.ACTION_SERVLET_KEY, this); 
      initModuleConfigFactory(); 
      // Initialize modules as needed 
      ModuleConfig moduleConfig =initModuleConfig("", config); 
      initModuleMessageResources(moduleConfig); 
      initModuleDataSources(moduleConfig); 
      initModulePlugIns(moduleConfig); 
      moduleConfig.freeze(); 
   
      Enumeration names =getServletConfig().getInitParameterNames(); 
      while (names.hasMoreElements()) { 
        String name = (String)namesnextElement(); 
        if (!name.startsWith("config/")) { 
          continue; 
        } 
        String prefix =name.substring(6); 
        moduleConfig = initModuleConfig 
          (prefix,getServletConfig().getInitParameter(name)); 
        initModuleMessageResources(moduleConfig); 
        initModuleDataSources(moduleConfig); 
        initModulePlugIns(moduleConfig); 
        moduleConfig.freeze(); 
      } 
   
      this.initModulePrefixes(this.getServletContext()); 
   
      thisdestroyConfigDigester(); 
    } catch (UnavailableException ex) { 
      throw ex; 
    } catch (Throwable t) { 
  
      // The follow error message is not retrieved from internal message 
      // resources as they may not have been able to have been 
      // initialized 
      logerror("Unable to initialize Struts ActionServlet due to an " 
        + "unexpected exception or error thrown, so marking the " 
        + "servlet as unavailable. Mostlikely, this is due to an " 
        + "incorrect or missing library dependency.", t); 
      throw new UnavailableException(t.getMessage()); 
    }   
} 

/** 
   * <p>Initialize our internal MessageResourcesbundle</p> 
   * 
   * @exception ServletException if we cannotinitialize these resources 
   */ 
  protectedvoidinitInternal() throwsServletException { 
  
    // :FIXME: Document UnavailableException 
  
    try { 
      internal = MessageResourcesgetMessageResources(internalName); 
    } catch (MissingResourceException e) { 
      log.error("Cannot load internal resources from '"+ internalName+ "'", 
        e); 
      throw new UnavailableException 
        ("Cannot load internal resources from '"+ internalName+ "'"); 
    } 
  
} 

/** 
   * Create and return an instance of <code>MessageResources</code> for the 
   * created by the default <code>MessageResourcesFactory</code>. 
   * 
   * @param config Configuration parameterfor this message bundle. 
   */ 
  publicsynchronizedstaticMessageResources getMessageResources(String config) { 
  
    if (defaultFactory == null) { 
      defaultFactory =MessageResourcesFactory.createFactory(); 
    } 
  
    return defaultFactory.createResources(config); 
} 

/** 
   * Create and return a <code>MessageResourcesFactory</code> instance ofthe 
   * appropriate class, which can be used tocreate customized 
   * <code>MessageResources</code>instances If no such factory can be 
   * created, return <code>null</code> instead 
   */ 
  publicstaticMessageResourcesFactory createFactory(){ 
  
    // Construct a new instance of the specified factory class 
    try { 
      if (clazz == null) 
        clazz = RequestUtils.applicationClass(factoryClass); 
      MessageResourcesFactory factory = 
        (MessageResourcesFactory) clazz.newInstance(); 
      return (factory); 
    } catch (Throwable t) { 
      LOG.error("MessageResourcesFactory.createFactory",t); 
      return (null); 
    } 
  
} 

/** 
   * <p>Initialize other global characteristics ofthe controller servlet</p> 
   * 
   * @exception ServletException if we cannotinitialize these resources 
   */ 
  protectedvoidinitOther() throwsServletException { 
  
    String value = null; 
    value =getServletConfig().getInitParameter("config"); 
    if (value != null) { 
      config = value; 
    } 
  
    // Backwards compatibility for form beans of Java wrapper classes 
    // Set to true for strict Struts 0 compatibility 
    value =getServletConfig().getInitParameter("convertNull"); 
    if ("true".equalsIgnoreCase(value) 
      || "yes".equalsIgnoreCase(value) 
      || "on".equalsIgnoreCase(value) 
      || "y".equalsIgnoreCase(value) 
      || "1".equalsIgnoreCase(value)) { 
  
      convertNull = true; 
    } 
  
    if (convertNull) { 
      ConvertUtils.deregister(); 
      ConvertUtils.register(new BigDecimalConverter(null), BigDecimal.class); 
      ConvertUtils.register(new BigIntegerConverter(null), BigInteger.class); 
      ConvertUtils.register(new BooleanConverter(null), Boolean.class); 
      ConvertUtils.register(new ByteConverter(null), Byte.class); 
      ConvertUtils.register(new CharacterConverter(null), Character.class); 
      ConvertUtils.register(new DoubleConverter(null), Double.class); 
      ConvertUtils.register(new FloatConverter(null), Float.class); 
      ConvertUtils.register(new IntegerConverter(null), Integer.class); 
      ConvertUtils.register(new LongConverter(null), Long.class); 
      ConvertUtils.register(new ShortConverter(null), Short.class); 
    } 
  
} 

/** 
 * <p>Initialize the servlet mapping under which our controller servlet 
 * is being accessed. This will be used in the <code>&html:form></code> 
 * tag to generate correct destination URLs for form submissions.</p> 
 * 
 * @throws ServletException if error happens while scanning web.xml 
 */ 
protected void initServlet() throws ServletException { 
 
  // Remember our servlet name 
  this.servletName = getServletConfig().getServletName(); 
 
  // Prepare a Digester to scan the web application deployment descriptor 
  Digester digester = new Digester(); 
  digester.push(this); 
  digester.setNamespaceAware(true); 
  digester.setValidating(false); 
 
  // Register our local copy of the DTDs that we can find 
  for (int i = 0; i < registrations.length; i += 2) { 
    URL url = this.getClass().getResource(registrations[i+1]); 
    if (url != null) { 
      digester.register(registrations[i], url.toString()); 
    } 
  } 
 
  // Configure the processing rules that we need 
  digester.addCallMethod("web-app/servlet-mapping", 
              "addServletMapping", 2); 
  digester.addCallParam("web-app/servlet-mapping/servlet-name", 0); 
  digester.addCallParam("web-app/servlet-mapping/url-pattern", 1); 
 
  // Process the web application deployment descriptor 
  if (log.isDebugEnabled()) { 
    log.debug("Scanning web.xml for controller servlet mapping"); 
  } 
 
  InputStream input = 
    getServletContext().getResourceAsStream("/WEB-INF/web.xml"); 
 
  if (input == null) { 
    log.error(internal.getMessage("configWebXml")); 
    throw new ServletException(internal.getMessage("configWebXml")); 
  } 
 
  try { 
    digester.parse(input); 
 
  } catch (IOException e) { 
    log.error(internal.getMessage("configWebXml"), e); 
    throw new ServletException(e); 
 
  } catch (SAXException e) { 
    log.error(internal.getMessage("configWebXml"), e); 
    throw new ServletException(e); 
 
  } finally { 
    try { 
      input.close(); 
    } catch (IOException e) { 
      log.error(internal.getMessage("configWebXml"), e); 
      throw new ServletException(e); 
    } 
  } 
 
  // Record a servlet context attribute (if appropriate) 
  if (log.isDebugEnabled()) { 
    logdebug("Mapping for servlet '" + servletName + "' = '" + 
      servletMapping + "'"); 
  } 
 
  if (servletMapping != null) { 
    getServletContext().setAttribute(Globals.SERVLET_KEY, servletMapping); 
  } 
 
} 

public void init() throws ServletException { 
  
 try { 
    //初始化资源类 
   initInternal(); 
   //注册转换类 
   initOther(); 
   //利用digester读取webxml文件并且将其放到servletContext中 
   initServlet(); 
   getServletContext().setAttribute(Globals.ACTION_SERVLET_KEY, this); 
    
   initModuleConfigFactory(); 
   ModuleConfig moduleConfig = initModuleConfig("", config); 
   initModuleMessageResources(moduleConfig); 
   initModuleDataSources(moduleConfig); 
   initModulePlugIns(moduleConfig); 
   moduleConfig.freeze(); 
 
   Enumeration names = getServletConfig().getInitParameterNames(); 
   while (names.hasMoreElements()) { 
     String name = (String) names.nextElement(); 
     if (!name.startsWith("config/")) { 
       continue; 
     } 
     String prefix = name.substring(6); 
     moduleConfig = initModuleConfig 
       (prefix, getServletConfig()getInitParameter(name)); 
     initModuleMessageResources(moduleConfig); 
     initModuleDataSources(moduleConfig); 
     initModulePlugIns(moduleConfig); 
     moduleConfig.freeze(); 
   } 
 
   this.initModulePrefixes(this.getServletContext()); 
 
   this.destroyConfigDigester(); 
 } catch (UnavailableException ex) { 
   throw ex; 
 } catch (Throwable t) { 
   log.error("Unable to initialize Struts ActionServlet due to an " 
     + "unexpected exception or error thrown, so marking the " 
     + "servlet as unavailable Most likely, this is due to an " 
     + "incorrect or missing library dependency", t); 
   throw new UnavailableException(t.getMessage()); 
 }   
} 

public static final String ACTION_SERVLET_KEY= "org.apache.struts.action.ACTION_SERVLET"; 

protected voidinitModuleConfigFactory(){ 
    String configFactory =getServletConfig().getInitParameter("configFactory"); 
    if (configFactory != null) { 
      ModuleConfigFactory.setFactoryClass(configFactory); 
    } 
} 

public static void setFactoryClass(String factoryClass) { 
    ModuleConfigFactory.factoryClass = factoryClass; 
    ModuleConfigFactory.clazz = null; 
  } 

protected static String factoryClass = 
    "org.apache.struts.config.impl.DefaultModuleConfigFactory"; 
} 

protected ModuleConfig initModuleConfig(Stringprefix, String paths) 
    throws ServletException { 
  
    // :FIXME: Document UnavailableException? (Doesn't actually throw anything) 
  
    if (log.isDebugEnabled()) { 
      log.debug( 
        "Initializing module path '" 
          + prefix 
          + "' configuration from '" 
          + paths 
          + "'"); 
    } 
  
    // Parse the configuration for this module 
    ModuleConfigFactory factoryObject= ModuleConfigFactory.createFactory(); 
    ModuleConfig config =factoryObject.createModuleConfig(prefix); 
  
    // Configure the Digester instance we will use 
    Digester digester =initConfigDigester(); 
  
    // Process each specified resource path 
    while (paths.length() > 0) { 
      digester.push(config); 
      String path = null; 
      int comma = paths.indexOf(','); 
      if (comma >= 0) { 
        path =paths.substring(0, comma).trim(); 
        paths =paths.substring(comma + 1); 
      } else { 
        path = pathstrim(); 
        paths = ""; 
      } 
  
      if (pathlength() < 1){ 
        break; 
      } 
  
      this.parseModuleConfigFile(digester,path); 
    } 
  
    getServletContext().setAttribute( 
      Globals.MODULE_KEY +config.getPrefix(), 
      config); 
  
  
    // Force creation and registration of DynaActionFormClass instances 
    // for all dynamic form beans we wil be using 
    FormBeanConfig fbs[] =config.findFormBeanConfigs(); 
    for (int i = 0; i < fbs.length; i++) { 
      if (fbs[i].getDynamic()) { 
        fbs[i].getDynaActionFormClass(); 
      } 
    } 
  
    return config; 
}