Struts包介紹
包名 |
說明 |
org.apache.struts2. components |
該包封裝視圖組件,Struts2在視圖組件上有了很大加強,不僅增加了組件的屬性個數,更新增了幾個非常有用的組件,如updownselect、doubleselect、datetimepicker、token、tree等。 另外,Struts2可視化視圖組件開始支持主題(theme),缺省情況下,使用自帶的缺省主題,如果要自定義頁面效果,需要將組件的theme屬性設置爲simple。 |
org.apache.struts2. config |
該包定義與配置相關的接口和類。實際上,工程中的xml和properties文件的讀取和解析都是由WebWork完成的,Struts只做了少量的工作。 |
org.apache.struts2.dispatcher |
Struts2的核心包,最重要的類都放在該包中。 |
org.apache.struts2.impl |
該包只定義了3個類,他們是StrutsActionProxy、StrutsActionProxyFactory、StrutsObjectFactory,這三個類都是對xwork的擴展。 |
org.apache.struts2.interceptor |
定義內置的截攔器。 |
org.apache.struts2.util |
實用包。 |
org.apache.struts2.validators |
只定義了一個類:DWRValidator。 |
org.apache.struts2.views |
提供freemarker、jsp、velocity等不同類型的頁面呈現。 |
下表是對一些重要類的說明:
類名 |
說明 |
org.apache.struts2.dispatcher. Dispatcher |
該類有兩個作用: 1、初始化 2、調用指定的Action的execute()方法。 |
org.apache.struts2.dispatcher. FilterDispatcher |
這是一個過濾器。文檔中已明確說明,如果沒有經驗,配置時請將url-pattern的值設成/*。 該類有四個作用: 1、執行Action 2、清理ActionContext,避免內存泄漏 3、處理靜態內容(Serving static content) 4、爲請求啓動xwork’s的截攔器鏈。 |
com.opensymphony.xwork2. ActionProxy |
Action的代理接口。 |
com.opensymphony.xwork2. ctionProxyFactory |
生產ActionProxy的工廠。 |
com.opensymphony.xwork2.ActionInvocation |
負責調用Action和截攔器。 |
com.opensymphony.xwork2.config.providers. XmlConfigurationProvider |
負責Struts2的配置文件的解析。 |
- public void init() {
- if (configurationManager == null) {
- configurationManager = new ConfigurationManager(BeanSelectionProvider.DEFAULT_BEAN_NAME);
- }
- init_DefaultProperties(); // [1]
- init_TraditionalXmlConfigurations(); // [2]
- init_LegacyStrutsProperties(); // [3]
- init_ZeroConfiguration(); // [4]
- init_CustomConfigurationProviders(); // [5]
- init_MethodConfigurationProvider();
- init_FilterInitParameters() ; // [6]
- init_AliasStandardObjects() ; // [7]
- Container container = init_PreloadConfiguration();
- init_CheckConfigurationReloading(container);
- init_CheckWebLogicWorkaround(container);
- }
- private void init_DefaultProperties() {
- configurationManager.addConfigurationProvider(new DefaultPropertiesProvider());
- }
- //DefaultPropertiesProvider
- public void register(ContainerBuilder builder, LocatableProperties props)
- throws ConfigurationException {
- Settings defaultSettings = null;
- try {
- defaultSettings = new PropertiesSettings("org/apache/struts2/default");
- } catch (Exception e) {
- throw new ConfigurationException("Could not find or error in org/apache/struts2/default.properties", e);
- }
- loadSettings(props, defaultSettings);
- }
- //PropertiesSettings
- //讀取org/apache/struts2/default.properties的配置信息,如果項目中需要覆蓋,可以在classpath裏的struts.properties裏覆寫
- public PropertiesSettings(String name) {
- URL settingsUrl = ClassLoaderUtils.getResource(name + ".properties", getClass());
- if (settingsUrl == null) {
- LOG.debug(name + ".properties missing");
- settings = new LocatableProperties();
- return;
- }
- //settings的類型爲LocatableProperties,繼承Properties
- settings = new LocatableProperties(new LocationImpl(null, settingsUrl.toString()));
- // Load settings
- InputStream in = null;
- try {
- in = settingsUrl.openStream();
- settings.load(in);
- } catch (IOException e) {
- throw new StrutsException("Could not load " + name + ".properties:" + e, e);
- } finally {
- if(in != null) {
- try {
- in.close();
- } catch(IOException io) {
- LOG.warn("Unable to close input stream", io);
- }
- }
- }
- }
- private void init_TraditionalXmlConfigurations() {
- //首先讀取web.xml中的config初始參數值
- //如果沒有配置就使用默認的"struts-default.xml,struts-plugin.xml,struts.xml",
- //這兒就可以看出爲什麼默認的配置文件必須取名爲這三個名稱了
- //如果不想使用默認的名稱,直接在web.xml中配置config初始參數即可
- String configPaths = initParams.get("config");
- if (configPaths == null) {
- configPaths = DEFAULT_CONFIGURATION_PATHS;
- }
- String[] files = configPaths.split("//s*[,]//s*");
- //依次解析配置文件,xwork.xml單獨解析
- for (String file : files) {
- if (file.endsWith(".xml")) {
- if ("xwork.xml".equals(file)) {
- configurationManager.addConfigurationProvider(new XmlConfigurationProvider(file, false));
- } else {
- configurationManager.addConfigurationProvider(new StrutsXmlConfigurationProvider(file, false, servletContext));
- }
- } else {
- throw new IllegalArgumentException("Invalid configuration file name");
- }
- }
- }
- protected PackageConfig addPackage(Element packageElement) throws ConfigurationException {
- PackageConfig.Builder newPackage = buildPackageContext(packageElement);
- if (newPackage.isNeedsRefresh()) {
- return newPackage.build();
- }
- if (LOG.isDebugEnabled()) {
- LOG.debug("Loaded " + newPackage);
- }
- // add result types (and default result) to this package
- addResultTypes(newPackage, packageElement);
- // load the interceptors and interceptor stacks for this package
- loadInterceptors(newPackage, packageElement);
- // load the default interceptor reference for this package
- loadDefaultInterceptorRef(newPackage, packageElement);
- // load the default class ref for this package
- loadDefaultClassRef(newPackage, packageElement);
- // load the global result list for this package
- loadGlobalResults(newPackage, packageElement);
- // load the global exception handler list for this package
- loadGobalExceptionMappings(newPackage, packageElement);
- // get actions
- NodeList actionList = packageElement.getElementsByTagName("action");
- for (int i = 0; i < actionList.getLength(); i++) {
- Element actionElement = (Element) actionList.item(i);
- addAction(actionElement, newPackage);
- }
- // load the default action reference for this package
- loadDefaultActionRef(newPackage, packageElement);
- PackageConfig cfg = newPackage.build();
- configuration.addPackageConfig(cfg.getName(), cfg);
- return cfg;
- }
- private List loadConfigurationFiles(String fileName, Element includeElement) {
- List<Document> docs = new ArrayList<Document>();
- if (!includedFileNames.contains(fileName)) {
- ...........
- 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();
- //解析每個action配置是,對於include文件可以使用通配符*來進行配置
- //如Struts.xml中可配置成<include file="actions_*.xml"/>
- if (nodeName.equals("include")) {
- String includeFileName = child.getAttribute("file");
- if(includeFileName.indexOf('*') != -1 ) {
- // handleWildCardIncludes(includeFileName, docs, child);
- ClassPathFinder wildcardFinder = new ClassPathFinder();
- wildcardFinder.setPattern(includeFileName);
- Vector<String> wildcardMatches = wildcardFinder.findMatches();
- for (String match : wildcardMatches) {
- docs.addAll(loadConfigurationFiles(match, child));
- }
- }
- else {
- docs.addAll(loadConfigurationFiles(includeFileName, child));
- }
- }
- }
- }
- docs.add(doc);
- loadedFileUrls.add(url.toString());
- }
- }
- return docs;
- }
- public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
- HttpServletRequest request = (HttpServletRequest) req;
- HttpServletResponse response = (HttpServletResponse) res;
- ServletContext servletContext = getServletContext();
- String timerKey = "FilterDispatcher_doFilter: ";
- try {
- UtilTimerStack.push(timerKey);
- //根據content type來使用不同的Request封裝,可以參見Dispatcher的wrapRequest
- request = prepareDispatcherAndWrapRequest(request, response);
- ActionMapping mapping;
- try {
- //根據url取得對應的Action的配置信息--ActionMapping,actionMapper是通過Container的inject注入的
- mapping = actionMapper.getMapping(request, dispatcher.getConfigurationManager());
- } catch (Exception ex) {
- LOG.error("error getting ActionMapping", ex);
- dispatcher.sendError(request, response, servletContext, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex);
- return;
- }
- //如果找不到對應的action配置,則直接返回。比如你輸入***.jsp等等
- //這兒有個例外,就是如果path是以“/struts”開頭,則到初始參數packages配置的包路徑去查找對應的靜態資源並輸出到頁面流中,當然.class文件除外。如果再沒有則跳轉到404
- if (mapping == null) {
- // there is no action in this request, should we look for a static resource?
- String resourcePath = RequestUtils.getServletPath(request);
- if ("".equals(resourcePath) && null != request.getPathInfo()) {
- resourcePath = request.getPathInfo();
- }
- if (serveStatic && resourcePath.startsWith("/struts")) {
- String name = resourcePath.substring("/struts".length());
- findStaticResource(name, request, response);
- } else {
- // this is a normal request, let it pass through
- chain.doFilter(request, response);
- }
- // The framework did its job here
- return;
- }
- //正式開始執行Action的方法了
- dispatcher.serviceAction(request, response, servletContext, mapping);
- } finally {
- try {
- ActionContextCleanUp.cleanUp(req);
- } finally {
- UtilTimerStack.pop(timerKey);
- }
- }
- }
- public void serviceAction(HttpServletRequest request, HttpServletResponse response, ServletContext context,
- ActionMapping mapping) throws ServletException {
- Map<String, Object> extraContext = createContextMap(request, response, mapping, context);
- // If there was a previous value stack, then create a new copy and pass it in to be used by the new Action
- ValueStack stack = (ValueStack) request.getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);
- if (stack != null) {
- extraContext.put(ActionContext.VALUE_STACK, ValueStackFactory.getFactory().createValueStack(stack));
- }
- String timerKey = "Handling request from Dispatcher";
- try {
- UtilTimerStack.push(timerKey);
- String namespace = mapping.getNamespace();
- String name = mapping.getName();
- String method = mapping.getMethod();
- Configuration config = configurationManager.getConfiguration();
- ActionProxy proxy = config.getContainer().getInstance(ActionProxyFactory.class).createActionProxy(namespace, name, extraContext, true, false);
- proxy.setMethod(method);
- request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, proxy.getInvocation().getStack());
- // if the ActionMapping says to go straight to a result, do it!
- if (mapping.getResult() != null) {
- Result result = mapping.getResult();
- result.execute(proxy.getInvocation());
- } else {
- proxy.execute();
- }
- // If there was a previous value stack then set it back onto the request
- if (stack != null) {
- request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, stack);
- }
- } catch (ConfigurationException e) {
- LOG.error("Could not find action or result", e);
- sendError(request, response, context, HttpServletResponse.SC_NOT_FOUND, e);
- } catch (Exception e) {
- throw new ServletException(e);
- } finally {
- UtilTimerStack.pop(timerKey);
- }
- }
- public HashMap<String,Object> createContextMap(Map requestMap,
- Map parameterMap,
- Map sessionMap,
- Map applicationMap,
- HttpServletRequest request,
- HttpServletResponse response,
- ServletContext servletContext) {
- HashMap<String,Object> extraContext = new HashMap<String,Object>();
- extraContext.put(ActionContext.PARAMETERS, new HashMap(parameterMap));
- extraContext.put(ActionContext.SESSION, sessionMap);
- extraContext.put(ActionContext.APPLICATION, applicationMap);
- Locale locale;
- if (defaultLocale != null) {
- locale = LocalizedTextUtil.localeFromString(defaultLocale, request.getLocale());
- } else {
- locale = request.getLocale();
- }
- extraContext.put(ActionContext.LOCALE, locale);
- //extraContext.put(ActionContext.DEV_MODE, Boolean.valueOf(devMode));
- extraContext.put(StrutsStatics.HTTP_REQUEST, request);
- extraContext.put(StrutsStatics.HTTP_RESPONSE, response);
- extraContext.put(StrutsStatics.SERVLET_CONTEXT, servletContext);
- // helpers to get access to request/session/application scope
- extraContext.put("request", requestMap);
- extraContext.put("session", sessionMap);
- extraContext.put("application", applicationMap);
- extraContext.put("parameters", parameterMap);
- AttributeMap attrMap = new AttributeMap(extraContext);
- extraContext.put("attr", attrMap);
- return extraContext;
- }
- public void init(ActionProxy proxy) {
- this.proxy = proxy;
- Map contextMap = createContextMap();
- //設置ActionContext,把ActionInvocation和Action壓入ValueStack
- ActionContext actionContext = ActionContext.getContext();
- if(actionContext != null) {
- actionContext.setActionInvocation(this);
- }
- //創建Action,可以看出Struts2裏是每次請求都新建一個Action,careateAction方法可以自己參考
- createAction(contextMap);
- if (pushAction) {
- stack.push(action);
- contextMap.put("action", action);
- }
- invocationContext = new ActionContext(contextMap);
- invocationContext.setName(proxy.getActionName());
- List interceptorList = new ArrayList(proxy.getConfig().getInterceptors());
- interceptors = interceptorList.iterator();
- }
- protected void createAction(Map contextMap) {
- String timerKey = "actionCreate: "+proxy.getActionName();
- try {
- UtilTimerStack.push(timerKey);
- //這兒默認建立Action是StrutsObjectFactory,實際中我使用的時候都是使用Spring創建的Action,這個時候使用的是SpringObjectFactory
- action = objectFactory.buildAction(proxy.getActionName(), proxy.getNamespace(), proxy.getConfig(), contextMap);
- }
- .......
- catch (Exception e) {
- ........
- throw new XWorkException(gripe, e, proxy.getConfig());
- } finally {
- UtilTimerStack.pop(timerKey);
- }
- if (actionEventListener != null) {
- action = actionEventListener.prepare(action, stack);
- }
- }
- public String invoke() throws Exception {
- String profileKey = "invoke: ";
- try {
- UtilTimerStack.push(profileKey);
- if (executed) {
- throw new IllegalStateException("Action has already executed");
- }
- //先執行interceptors
- if (interceptors.hasNext()) {
- final InterceptorMapping interceptor = (InterceptorMapping) interceptors.next();
- UtilTimerStack.profile("interceptor: "+interceptor.getName(),
- new UtilTimerStack.ProfilingBlock<String>() {
- public String doProfiling() throws Exception {
- resultCode = interceptor.getInterceptor().intercept(DefaultActionInvocation.this);
- return null;
- }
- });
- } else {
- //interceptor執行完了之後執行action
- resultCode = invokeActionOnly();
- }
- if (!executed) {
- if (preResultListeners != null) {
- for (Iterator iterator = preResultListeners.iterator();
- iterator.hasNext();) {
- PreResultListener listener = (PreResultListener) iterator.next();
- String _profileKey="preResultListener: ";
- try {
- UtilTimerStack.push(_profileKey);
- listener.beforeResult(this, resultCode);
- }
- finally {
- UtilTimerStack.pop(_profileKey);
- }
- }
- }
- // now execute the result, if we're supposed to
- if (proxy.getExecuteResult()) {
- executeResult();
- }
- executed = true;
- }
- return resultCode;
- }
- finally {
- UtilTimerStack.pop(profileKey);
- }
- }
- protected String invokeAction(Object action, ActionConfig actionConfig) throws Exception {
- String methodName = proxy.getMethod();
- String timerKey = "invokeAction: "+proxy.getActionName();
- try {
- UtilTimerStack.push(timerKey);
- boolean methodCalled = false;
- Object methodResult = null;
- Method method = null;
- try {
- //獲得Action對應的方法
- method = getAction().getClass().getMethod(methodName, new Class[0]);
- } catch (NoSuchMethodException e) {
- try {
- //如果沒有對應的方法,則使用do+Xxxx來再次獲得方法
- String altMethodName = "do" + methodName.substring(0, 1).toUpperCase() + methodName.substring(1);
- method = getAction().getClass().getMethod(altMethodName, new Class[0]);
- } catch (NoSuchMethodException e1) {
- .....
- }
- }
- if (!methodCalled) {
- methodResult = method.invoke(action, new Object[0]);
- }
- //根據不同的Result類型返回不同值
- if (methodResult instanceof Result) {
- this.explicitResult = (Result) methodResult;
- return null;
- } else {
- return (String) methodResult;
- }
- }
- ....
- } finally {
- UtilTimerStack.pop(timerKey);
- }
- }
- private void executeResult() throws Exception {
- //根據ResultConfig創建Result
- result = createResult();
- String timerKey = "executeResult: "+getResultCode();
- try {
- UtilTimerStack.push(timerKey);
- if (result != null) {
- //這兒正式執行:)
- //可以參考Result的實現,如用了比較多的ServletDispatcherResult,ServletActionRedirectResult,ServletRedirectResult
- result.execute(this);
- } else if (resultCode != null && !Action.NONE.equals(resultCode)) {
- throw new ConfigurationException("No result defined for action " + getAction().getClass().getName()
- + " and result " + getResultCode(), proxy.getConfig());
- } else {
- if (LOG.isDebugEnabled()) {
- LOG.debug("No result returned for action "+getAction().getClass().getName()+" at "+proxy.getConfig().getLocation());
- }
- }
- } finally {
- UtilTimerStack.pop(timerKey);
- }
- }
- public Result createResult() throws Exception {
- if (explicitResult != null) {
- Result ret = explicitResult;
- explicitResult = null;;
- return ret;
- }
- ActionConfig config = proxy.getConfig();
- Map results = config.getResults();
- ResultConfig resultConfig = null;
- synchronized (config) {
- try {
- //根據result名稱獲得ResultConfig,resultCode就是result的name
- resultConfig = (ResultConfig) results.get(resultCode);
- } catch (NullPointerException e) {
- }
- if (resultConfig == null) {
- //如果找不到對應name的ResultConfig,則使用name爲*的Result
- resultConfig = (ResultConfig) results.get("*");
- }
- }
- if (resultConfig != null) {
- try {
- //參照StrutsObjectFactory的代碼
- Result result = objectFactory.buildResult(resultConfig, invocationContext.getContextMap());
- return result;
- } catch (Exception e) {
- LOG.error("There was an exception while instantiating the result of type " + resultConfig.getClassName(), e);
- throw new XWorkException(e, resultConfig);
- }
- } else if (resultCode != null && !Action.NONE.equals(resultCode) && unknownHandler != null) {
- return unknownHandler.handleUnknownResult(invocationContext, proxy.getActionName(), proxy.getConfig(), resultCode);
- }
- return null;
- }
- //StrutsObjectFactory
- public Result buildResult(ResultConfig resultConfig, Map extraContext) throws Exception {
- String resultClassName = resultConfig.getClassName();
- if (resultClassName == null)
- return null;
- //創建Result,因爲Result是有狀態的,所以每次請求都新建一個
- Object result = buildBean(resultClassName, extraContext);
- reflectionProvider.setProperties(resultConfig.getParams(), result, extraContext);
- if (result instanceof Result)
- return (Result) result;
- throw new ConfigurationException(result.getClass().getName() + " does not implement Result.");
- }