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Struts example source code file (JspServlet.java)
The Struts JspServlet.java source code/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.struts2.jasper.servlet; import java.io.IOException; import java.lang.reflect.Constructor; import java.util.Enumeration; import javax.servlet.ServletConfig; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.struts2.jasper.Constants; import org.apache.struts2.jasper.EmbeddedServletOptions; import org.apache.struts2.jasper.Options; import org.apache.struts2.jasper.compiler.JspRuntimeContext; import org.apache.struts2.jasper.compiler.Localizer; import org.apache.struts2.jasper.security.SecurityUtil; import org.apache.juli.logging.Log; import org.apache.juli.logging.LogFactory; import org.apache.PeriodicEventListener; /** * The JSP engine (a.k.a Jasper). * * The servlet container is responsible for providing a * URLClassLoader for the web application context Jasper * is being used in. Jasper will try get the Tomcat * ServletContext attribute for its ServletContext class * loader, if that fails, it uses the parent class loader. * In either case, it must be a URLClassLoader. * * @author Anil K. Vijendran * @author Harish Prabandham * @author Remy Maucherat * @author Kin-man Chung * @author Glenn Nielsen */ public class JspServlet extends HttpServlet implements PeriodicEventListener { // Logger private Log log = LogFactory.getLog(JspServlet.class); private ServletContext context; private ServletConfig config; private Options options; private JspRuntimeContext rctxt; /* * Initializes this JspServlet. */ public void init(ServletConfig config) throws ServletException { super.init(config); this.config = config; this.context = config.getServletContext(); // Initialize the JSP Runtime Context // Check for a custom Options implementation String engineOptionsName = config.getInitParameter("engineOptionsClass"); if (engineOptionsName != null) { // Instantiate the indicated Options implementation try { ClassLoader loader = Thread.currentThread() .getContextClassLoader(); Class engineOptionsClass = loader.loadClass(engineOptionsName); Class[] ctorSig = { ServletConfig.class, ServletContext.class }; Constructor ctor = engineOptionsClass.getConstructor(ctorSig); Object[] args = { config, context }; options = (Options) ctor.newInstance(args); } catch (Throwable e) { // Need to localize this. log.warn("Failed to load engineOptionsClass", e); // Use the default Options implementation options = new EmbeddedServletOptions(config, context); } } else { // Use the default Options implementation options = new EmbeddedServletOptions(config, context); } rctxt = new JspRuntimeContext(context, options); if (log.isDebugEnabled()) { log.debug(Localizer.getMessage("jsp.message.scratch.dir.is", options.getScratchDir().toString())); log.debug(Localizer.getMessage("jsp.message.dont.modify.servlets")); } } /** * Returns the number of JSPs for which JspServletWrappers exist, i.e., * the number of JSPs that have been loaded into the webapp with which * this JspServlet is associated. * * <p>This info may be used for monitoring purposes. * * @return The number of JSPs that have been loaded into the webapp with * which this JspServlet is associated */ public int getJspCount() { return this.rctxt.getJspCount(); } /** * Resets the JSP reload counter. * * @param count Value to which to reset the JSP reload counter */ public void setJspReloadCount(int count) { this.rctxt.setJspReloadCount(count); } /** * Gets the number of JSPs that have been reloaded. * * <p>This info may be used for monitoring purposes. * * @return The number of JSPs (in the webapp with which this JspServlet is * associated) that have been reloaded */ public int getJspReloadCount() { return this.rctxt.getJspReloadCount(); } /** * <p>Look for a precompilation request as described in * Section 8.4.2 of the JSP 1.2 Specification. <strong>WARNING - * we cannot use <code>request.getParameter() for this, because * that will trigger parsing all of the request parameters, and not give * a servlet the opportunity to call * <code>request.setCharacterEncoding() first. * * @param request The servlet requset we are processing * * @exception ServletException if an invalid parameter value for the * <code>jsp_precompile parameter name is specified */ boolean preCompile(HttpServletRequest request) throws ServletException { String queryString = request.getQueryString(); if (queryString == null) { return (false); } int start = queryString.indexOf(Constants.PRECOMPILE); if (start < 0) { return (false); } queryString = queryString.substring(start + Constants.PRECOMPILE.length()); if (queryString.length() == 0) { return (true); // ?jsp_precompile } if (queryString.startsWith("&")) { return (true); // ?jsp_precompile&foo=bar... } if (!queryString.startsWith("=")) { return (false); // part of some other name or value } int limit = queryString.length(); int ampersand = queryString.indexOf("&"); if (ampersand > 0) { limit = ampersand; } String value = queryString.substring(1, limit); if (value.equals("true")) { return (true); // ?jsp_precompile=true } else if (value.equals("false")) { // Spec says if jsp_precompile=false, the request should not // be delivered to the JSP page; the easiest way to implement // this is to set the flag to true, and precompile the page anyway. // This still conforms to the spec, since it says the // precompilation request can be ignored. return (true); // ?jsp_precompile=false } else { throw new ServletException("Cannot have request parameter " + Constants.PRECOMPILE + " set to " + value); } } public void service (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String jspUri = null; String jspFile = (String) request.getAttribute(Constants.JSP_FILE); if (jspFile != null) { // JSP is specified via <jsp-file> in Other Struts examples (source code examples)Here is a short list of links related to this Struts JspServlet.java source code file: |
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