org.apache.jasper.servlet.JspServlet Maven / Gradle / Ivy
/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed 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.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.jasper.Constants;
import org.apache.jasper.EmbeddedServletOptions;
import org.apache.jasper.Options;
import org.apache.jasper.compiler.JspRuntimeContext;
import org.apache.jasper.compiler.Localizer;
/**
* 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 {
// Logger
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.
// 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);
}
/**
* 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.
*
* 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.
*
*
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();
}
/**
*
Look for a precompilation request as described in
* Section 8.4.2 of the JSP 1.2 Specification. WARNING -
* we cannot use request.getParameter() for this, because
* that will trigger parsing all of the request parameters, and not give
* a servlet the opportunity to call
* request.setCharacterEncoding() first.
*
* @param request The servlet requset we are processing
*
* @exception ServletException if an invalid parameter value for the
* 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 in declaration
jspUri = jspFile;
} else {
/*
* Check to see if the requested JSP has been the target of a
* RequestDispatcher.include()
*/
jspUri = (String) request.getAttribute(Constants.INC_SERVLET_PATH);
if (jspUri != null) {
/*
* Requested JSP has been target of
* RequestDispatcher.include(). Its path is assembled from the
* relevant javax.servlet.include.* request attributes
*/
String pathInfo = (String) request.getAttribute(
"javax.servlet.include.path_info");
if (pathInfo != null) {
jspUri += pathInfo;
}
} else {
/*
* Requested JSP has not been the target of a
* RequestDispatcher.include(). Reconstruct its path from the
* request's getServletPath() and getPathInfo()
*/
jspUri = request.getServletPath();
String pathInfo = request.getPathInfo();
if (pathInfo != null) {
jspUri += pathInfo;
}
}
}
try {
boolean precompile = preCompile(request);
serviceJspFile(request, response, jspUri, null, precompile);
} catch (RuntimeException e) {
throw e;
} catch (ServletException e) {
throw e;
} catch (IOException e) {
throw e;
} catch (Throwable e) {
throw new ServletException(e);
}
}
public void destroy() {
rctxt.destroy();
}
// -------------------------------------------------------- Private Methods
private void serviceJspFile(HttpServletRequest request,
HttpServletResponse response, String jspUri,
Throwable exception, boolean precompile)
throws ServletException, IOException {
JspServletWrapper wrapper =
(JspServletWrapper) rctxt.getWrapper(jspUri);
if (wrapper == null) {
synchronized(this) {
wrapper = (JspServletWrapper) rctxt.getWrapper(jspUri);
if (wrapper == null) {
// Check if the requested JSP page exists, to avoid
// creating unnecessary directories and files.
if (null == context.getResource(jspUri)) {
response.sendError(HttpServletResponse.SC_NOT_FOUND,
jspUri);
return;
}
boolean isErrorPage = exception != null;
wrapper = new JspServletWrapper(config, options, jspUri,
isErrorPage, rctxt);
rctxt.addWrapper(jspUri,wrapper);
}
}
}
wrapper.service(request, response, precompile);
}
}