關於Struts2.3.16 struts.xml 位置的坑，你肯定掉過~~~

　　最近在整一個簡單的框架，Spring4.0.6-Mybatis3-Struts2.3.16. 當中出現了一些坑讓人費解。

　　本來Spring配置都是完美ok的，但是栽在了struts的配置文件上。下面邊聽蝦米，邊開寫了 --！

 

　　背景：Spring4.0.6-Mybatis3-Struts2.3.16 + maven3

　　文件結構：

　　工程文件目錄結構

　　

　　配置文件目錄結構

　　

 

　　web.xml 中的struts配置

    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
        <init-param>
            <param-name>config</param-name>
            <param-value>struts-default.xml,struts-plugin.xml,/WEB-INF/classes/struts/action/struts.xml</param-value>
        </init-param>
    </filter>

　　按照spring的Listener的習慣，給配置文件前面加上了路徑/WEB-INF/classes/

　　跑到chrome里面一輸入地址，蹦出個404 action not found ... 

　　what happened ? 明明控制台沒有錯誤輸出的啊......

　　

　　輾轉反側,又加上了log4j來輸出日志，難道struts2這貨要依靠log4j來替自己說話?

　　果然，在配置了log4j之后，struts把他的不痛快吐了一地....

　　關於log4j的配置,童鞋們可以上百度，上谷歌，很詳細的有木有啊...

　

2014-08-07 17:06:02 INFO [com.opensymphony.xwork2.config.providers.XmlConfigurationProvider] Parsing configuration file [struts-default.xml]
2014-08-07 17:06:02 INFO [com.opensymphony.xwork2.config.providers.XmlConfigurationProvider] Unable to locate configuration files of the name struts-plugin.xml, skipping
2014-08-07 17:06:02 INFO [com.opensymphony.xwork2.config.providers.XmlConfigurationProvider] Parsing configuration file [struts-plugin.xml]
2014-08-07 17:06:02 INFO [com.opensymphony.xwork2.config.providers.XmlConfigurationProvider] Unable to locate configuration files of the name \WEB-INF\classes\struts/action/struts.xml, skipping
2014-08-07 17:06:02 INFO [com.opensymphony.xwork2.config.providers.XmlConfigurationProvider] Parsing configuration file [\WEB-INF\classes\struts/action/struts.xml]

　　很明顯，沒有加載到struts.xml文件，然后把百度和谷歌翻了個遍，大部分答案都是一樣的

　　1.當自定義struts的配置文件的時候需要加載 struts-default.xml,struts-plugin.xml 這兩個

　　2.struts2 加載配置文件是基於src目錄

　　當然上面這兩條是正確的.　但是有人說把/WEB-INF/classes/struts.xml 改成 ../struts.xml ，我還真沒成功....

　　why ?

　　

　　試了網上的幾種方法都不成功都，決定自己看sruts的源碼，斷點進入struts的內部一看究竟

　　(這里介紹一個eclipse的插件--Java Attach Source ：jar包源碼下載插件 , 直接在eclipse market里搜索安裝后,找到你想到下載源碼的jar包，

　　右鍵->Attach Java Source 然后看到progress 完成后就可以點開源碼了.)

　　(當想要研究某個框架的時候，需要用容器啟動斷點怎么辦？最好的辦法就是你寫一個類繼續它，然后配置里寫這個類，打上斷點就ok了。)

　　好直接上struts  org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter的代碼

public void init(FilterConfig filterConfig) throws ServletException {
        InitOperations init = new InitOperations();
        Dispatcher dispatcher = null;
        try {
            //初始化filterConfig
            FilterHostConfig config = new FilterHostConfig(filterConfig);
            //加載與log4j關聯的日志類
            init.initLogging(config);
            //初始化配置文件 大頭來了
            dispatcher = init.initDispatcher(config);
            //設置配置文件中的內容
            init.initStaticContentLoader(config, dispatcher);
            //后面這些是對 url 的解析與 action method 的執行
            prepare = new PrepareOperations(filterConfig.getServletContext(), dispatcher);
            execute = new ExecuteOperations(filterConfig.getServletContext(), dispatcher);
            this.excludedPatterns = init.buildExcludedPatternsList(dispatcher);
            
            postInit(dispatcher, filterConfig);
        } finally {
            if (dispatcher != null) {
                dispatcher.cleanUpAfterInit();
            }
            init.cleanup();
        }
    }

 

　　當啟動進入到StrutsPrepareAndExecuteFilter  類時就進入init方法.

　　看到這里的  filterConfig , 網上就有一大幫人說,自定義 struts.xml 時, param-name 要寫成filterConfig.

　　這是個坑,這里的filterConfig 和 param-name 中的值木有半毛錢關系.... 關於why寫config后面再細說.

    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
        <init-param>
            <param-name>filterConfig</param-name> <!-- 這里絕對是錯誤的，各位小心 -->
            <param-value>struts-default.xml,struts-plugin.xml,\WEB-INF\classes\struts/action/struts.xml</param-value>
        </init-param>
    </filter>

　　好，既然我們找到了加載配置文件的大頭,那么我們進入到 org.apache.struts2.dispatcher.ng.InitOperations 

　　dispatcher = init.initDispatcher(config); 一探天地吧.

public Dispatcher initDispatcher( HostConfig filterConfig ) {
        //創建Dispatcher filter
        Dispatcher dispatcher = createDispatcher(filterConfig);
        //類的初始化
        dispatcher.init();
        return dispatcher;
    }

　　進入到org.apache.struts2.dispatcher.Dispatcher  dispatcher.init();  ok , 凶手出來鳥~~~

    /**
     * Load configurations, including both XML and zero-configuration strategies,
     * and update optional settings, including whether to reload configurations and resource files.
     *注釋中有說到加載配置的順序
     * 1.加載xml文件
     * 2.加載 類似 struts.properties 文件
     * 3.更新操作設置
     * 4.配置是否自動reload加載
     */
    public void init() {

        if (configurationManager == null) {
            configurationManager = createConfigurationManager(DefaultBeanSelectionProvider.DEFAULT_BEAN_NAME);
        }

        try {
            //初始化FileManer
            init_FileManager();
            //加載struts.properties 文件 一般都在struts.xml文件中配置了
            init_DefaultProperties(); // [1]
            //加載struts.xml 文件
            init_TraditionalXmlConfigurations(); // [2]
            //解析配置文件、設置變量等等
            init_LegacyStrutsProperties(); // [3] //加載默認配置文件解析器 PropertiesConfigurationProvider configg provider
            init_CustomConfigurationProviders(); // [5] 加載用戶自定義的 configuration provider 
            init_FilterInitParameters() ; // [6] //struts.xml 重新加載相關
            init_AliasStandardObjects() ; // [7] //國際化相關
　　　　　　　　
            Container container = init_PreloadConfiguration();//   
            container.inject(this);
            init_CheckWebLogicWorkaround(container);

            if (!dispatcherListeners.isEmpty()) {
                for (DispatcherListener l : dispatcherListeners) {
                    l.dispatcherInitialized(this);
                }
            }
        } catch (Exception ex) {
            if (LOG.isErrorEnabled())
                LOG.error("Dispatcher initialization failed", ex);
            throw new StrutsException(ex);
        }
    }

 

　　我們具體到org.apache.struts2.dispatcher.Dispatcher init_TraditionalXmlConfigurations() 看怎么加載struts.xml的

private void init_TraditionalXmlConfigurations() {
        //這里就是我們在web.xml中需要些的param-name 的 name -> config 而不是網上所說的 filterConfig 
        String configPaths = initParams.get("config");
        if (configPaths == null) {
            configPaths = DEFAULT_CONFIGURATION_PATHS;
        }
        // 將我們要加載的struts 相關的 配置文件 如 struts.xml 但不支持struts*.xml
        String[] files = configPaths.split("\\s*[,]\\s*");
        for (String file : files) {
            if (file.endsWith(".xml")) {
                if ("xwork.xml".equals(file)) {
                    configurationManager.addContainerProvider(createXmlConfigurationProvider(file, false));
                } else {
                    //加載 xml 解釋器 ， 加載 struts.xml 到 configurationManager 中
                    configurationManager.addContainerProvider(createStrutsXmlConfigurationProvider(file, false, servletContext));
                }
            } else {
                throw new IllegalArgumentException("Invalid configuration file name");
            }
        }
    }

 

關鍵時刻到來了 

 Container container = init_PreloadConfiguration(); // 加載 struts.xml 配置文件  

 

 public static Iterator<URL> getResources(String resourceName, Class callingClass, boolean aggregate) throws IOException {
        //這里的resourceName 即 struts.xml 
        // callingClass 指類加載器的class
         AggregateIterator<URL> iterator = new AggregateIterator<URL>();

         iterator.addEnumeration(Thread.currentThread().getContextClassLoader().getResources(resourceName));

         if (!iterator.hasNext() || aggregate) {
             iterator.addEnumeration(ClassLoaderUtil.class.getClassLoader().getResources(resourceName));
         }

         if (!iterator.hasNext() || aggregate) {
             ClassLoader cl = callingClass.getClassLoader();

             if (cl != null) {
                 iterator.addEnumeration(cl.getResources(resourceName));
             }
         }

         if (!iterator.hasNext() && (resourceName != null) && ((resourceName.length() == 0) || (resourceName.charAt(0) != '/'))) { 
            //獲取 struts.xml 所在的根路徑
             return getResources('/' + resourceName, callingClass, aggregate);
         }

         return iterator;
     }
     
     
     
     package org.apache.struts2.dispatcher.Dispatcher
     
     private Container init_PreloadConfiguration() {
        // 獲取 xml 配置
        Configuration config = configurationManager.getConfiguration();
        Container container = config.getContainer();

        boolean reloadi18n = Boolean.valueOf(container.getInstance(String.class, StrutsConstants.STRUTS_I18N_RELOAD));
        LocalizedTextUtil.setReloadBundles(reloadi18n);

        ContainerHolder.store(container);

        return container;
    }

    package com.opensymphony.xwork2.config.ConfigurationManager
    
    public synchronized Configuration getConfiguration() {
        if (configuration == null) {
            setConfiguration(createConfiguration(defaultFrameworkBeanName));
            try {
                // 加載 配置解析器 providers
                configuration.reloadContainer(getContainerProviders());
            } catch (ConfigurationException e) {
                setConfiguration(null);
                throw new ConfigurationException("Unable to load configuration.", e);
            }
        } else {
            conditionalReload();
        }

        return configuration;
    }
    
    package com.opensymphony.xwork2.config.impl.DefaultConfiguration implements Configuration
    
    public synchronized List<PackageProvider> reloadContainer(List<ContainerProvider> providers) throws ConfigurationException {
    packageContexts.clear();
    loadedFileNames.clear();
    List<PackageProvider> packageProviders = new ArrayList<PackageProvider>();

    ContainerProperties props = new ContainerProperties();
    ContainerBuilder builder = new ContainerBuilder();
    Container bootstrap = createBootstrapContainer(providers);
    for (final ContainerProvider containerProvider : providers)
    {
        //類加載器注入 xml 解析器
        bootstrap.inject(containerProvider);
        // 執行各個解析器的init方法 , 有我們前面加載的proerties,xml 的解析器等等 -- 即加載文件操作
        containerProvider.init(this);
        // 注冊 xml 即 解析操作
        containerProvider.register(builder, props);
    }

 

 先執行 XmlConfigurationProvider 中的 init()

com.opensymphony.xwork2.config.providers
    public class XmlConfigurationProvider implements ConfigurationProvider {
    public void init(Configuration configuration) {
        this.configuration = configuration;
        this.includedFileNames = configuration.getLoadedFileNames();
        //加載 struts.xml 文檔
        loadDocuments(configFileName);
    }
    
    private void loadDocuments(String configFileName) {
        try {
            loadedFileUrls.clear();
            //繼續加載文檔
            documents = loadConfigurationFiles(configFileName, null);
        } catch (ConfigurationException e) {
            throw e;
        } catch (Exception e) {
            throw new ConfigurationException("Error loading configuration file " + configFileName, e);
        }
    }
    
    private List<Document> loadConfigurationFiles(String fileName, Element includeElement) {
        List<Document> docs = new ArrayList<Document>();
        List<Document> finalDocs = new ArrayList<Document>();
        if (!includedFileNames.contains(fileName)) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Loading action configurations from: " + fileName);
            }

            includedFileNames.add(fileName);

            Iterator<URL> urls = null;
            InputStream is = null;

            IOException ioException = null;
            try {
                // 亮點在此
                urls = getConfigurationUrls(fileName);
            } catch (IOException ex) {
                ioException = ex;
            }

            if (urls == null || !urls.hasNext()) {
                if (errorIfMissing) {
                    throw new ConfigurationException("Could not open files of the name " + fileName, ioException);
                } else {
                    if (LOG.isInfoEnabled()) {
                    // 沒有找到 配置文件的 日志輸出在此
                    LOG.info("Unable to locate configuration files of the name "
                            + fileName + ", skipping");
                    }
                    return docs;
                }
            }

            URL url = null;
            while (urls.hasNext()) {
                try {
                    url = urls.next();
                    //找到配置文件，並存在的 加載文件
                    is = fileManager.loadFile(url);

                    InputSource in = new InputSource(is);

                    in.setSystemId(url.toString());

                    docs.add(DomHelper.parse(in, dtdMappings));
                } catch (XWorkException e) {
                    if (includeElement != null) {
                        throw new ConfigurationException("Unable to load " + url, e, includeElement);
                    } else {
                        throw new ConfigurationException("Unable to load " + url, e);
                    }
                } catch (Exception e) {
                    throw new ConfigurationException("Caught exception while loading file " + fileName, e, includeElement);
                } finally {
                    if (is != null) {
                        try {
                            is.close();
                        } catch (IOException e) {
                            LOG.error("Unable to close input stream", e);
                        }
                    }
                }
            }

 

　　好，直接來最終的判斷struts,xml的文件路徑的方法，終於等到你...

　

 public static Iterator<URL> getResources(String resourceName, Class callingClass, boolean aggregate) throws IOException {
        //這里的resourceName 即 struts.xml 
        // callingClass 指類加載器的class
         AggregateIterator<URL> iterator = new AggregateIterator<URL>();
　　　　　// 在這里就獲取到了struts.xml 所在的path了
         iterator.addEnumeration(Thread.currentThread().getContextClassLoader().getResources(resourceName));
　　　　　///E:/Soft/tomcat-6.0.39-x64/apache-tomcat-6.0.39/webapps/TestDemos/WEB-INF/classes/struts/action/struts.xml 
　　　　　　　//原來他是從WEB-INF/classes 開始滴.... 真是愁死我了...
         if (!iterator.hasNext() || aggregate) {
             iterator.addEnumeration(ClassLoaderUtil.class.getClassLoader().getResources(resourceName));
         }

         if (!iterator.hasNext() || aggregate) {
             ClassLoader cl = callingClass.getClassLoader();

             if (cl != null) {
                 iterator.addEnumeration(cl.getResources(resourceName));
             }
         }

         if (!iterator.hasNext() && (resourceName != null) && ((resourceName.length() == 0) || (resourceName.charAt(0) != '/'))) { 
            
             return getResources('/' + resourceName, callingClass, aggregate);
         }

         return iterator;
     }

 　ok, struts2 加載配置文件到此結束了，接下來的就是 register 解析 注冊 配置文件了,看了近一天的源碼終於弄明白了......各種淚奔啊

　下面簡單貼下 解析過程的代碼了,解析的部分就類型xml的解析,獲取關鍵字,mapping配置文件中的action和result

// 各種做事情都是 這個provider 這里就是適配器模式來適配各種配置文件.xml,.propertis,.dtd等等
// N 個provider 循環執行
// for (final ContainerProvider containerProvider : providers)
        {
            bootstrap.inject(containerProvider);
            containerProvider.init(this);
            containerProvider.register(builder, props);
        }
        
package com.opensymphony.xwork2.config.providers.XmlConfigurationProvider implements ConfigurationProvider

public void register(ContainerBuilder containerBuilder, LocatableProperties props) throws ConfigurationException {
        if (LOG.isInfoEnabled()) {
            LOG.info("Parsing configuration file [" + configFileName + "]");
        }
        Map<String, Node> loadedBeans = new HashMap<String, Node>();
        for (Document doc : documents) {
            Element rootElement = doc.getDocumentElement();
            NodeList children = rootElement.getChildNodes();
            int childSize = children.getLength();

            for (int i = 0; i < childSize; i++) {
                Node childNode = children.item(i);

                if (childNode instanceof Element) {
                    Element child = (Element) childNode;

                    final String nodeName = child.getNodeName();
                    // 加載spring中的bean
                    if ("bean".equals(nodeName)) {
                        String type = child.getAttribute("type");
                        String name = child.getAttribute("name");
                        String impl = child.getAttribute("class");
                        String onlyStatic = child.getAttribute("static");
                        String scopeStr = child.getAttribute("scope");
                        boolean optional = "true".equals(child.getAttribute("optional"));
                        Scope scope = Scope.SINGLETON;
                        if ("default".equals(scopeStr)) {
                            scope = Scope.DEFAULT;
                        } else if ("request".equals(scopeStr)) {
                            scope = Scope.REQUEST;
                        } else if ("session".equals(scopeStr)) {
                            scope = Scope.SESSION;
                        } else if ("singleton".equals(scopeStr)) {
                            scope = Scope.SINGLETON;
                        } else if ("thread".equals(scopeStr)) {
                            scope = Scope.THREAD;
                        }

                        if (StringUtils.isEmpty(name)) {
                            name = Container.DEFAULT_NAME;
                        }

                        try {
                            Class cimpl = ClassLoaderUtil.loadClass(impl, getClass());
                            Class ctype = cimpl;
                            if (StringUtils.isNotEmpty(type)) {
                                ctype = ClassLoaderUtil.loadClass(type, getClass());
                            }
                            if ("true".equals(onlyStatic)) {
                                // Force loading of class to detect no class def found exceptions
                                cimpl.getDeclaredClasses();
                                containerBuilder.injectStatics(cimpl);
                            } else {
                                if (containerBuilder.contains(ctype, name)) {
                                    Location loc = LocationUtils.getLocation(loadedBeans.get(ctype.getName() + name));
                                    if (throwExceptionOnDuplicateBeans) {
                                        throw new ConfigurationException("Bean type " + ctype + " with the name " +
                                                name + " has already been loaded by " + loc, child);
                                    }
                                }

                                // Force loading of class to detect no class def found exceptions
                                cimpl.getDeclaredConstructors();

                                if (LOG.isDebugEnabled()) {
                                    LOG.debug("Loaded type:" + type + " name:" + name + " impl:" + impl);
                                }
                                containerBuilder.factory(ctype, name, new LocatableFactory(name, ctype, cimpl, scope, childNode), scope);
                            }
                            loadedBeans.put(ctype.getName() + name, child);
                        } catch (Throwable ex) {
                            if (!optional) {
                                throw new ConfigurationException("Unable to load bean: type:" + type + " class:" + impl, ex, childNode);
                            } else {
                                if (LOG.isDebugEnabled()) {
                                    LOG.debug("Unable to load optional class: #0", impl);
                                }
                            }
                        }
                        //解析struts.xml 中的action
                    } else if ("constant".equals(nodeName)) {
                        String name = child.getAttribute("name");
                        String value = child.getAttribute("value");
                        props.setProperty(name, value, childNode);
                    } else if (nodeName.equals("unknown-handler-stack")) {
                        List<UnknownHandlerConfig> unknownHandlerStack = new ArrayList<UnknownHandlerConfig>();
                        NodeList unknownHandlers = child.getElementsByTagName("unknown-handler-ref");
                        int unknownHandlersSize = unknownHandlers.getLength();

                        for (int k = 0; k < unknownHandlersSize; k++) {
                            Element unknownHandler = (Element) unknownHandlers.item(k);
                            unknownHandlerStack.add(new UnknownHandlerConfig(unknownHandler.getAttribute("name")));
                        }

                        if (!unknownHandlerStack.isEmpty())
                            configuration.setUnknownHandlerStack(unknownHandlerStack);
                    }
                }
            }
        }
    }

 

ok，現在struts 加載完了配置文件、就要進行后面的工作了，后面的內容如果有機會，將在下一篇文章中發出了

這篇有點小長，但是總體還是比較精細，歡迎各位來點評、拍磚.

 

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