Capturing JSP Content Within My Strut Action Servlet

Greenhorn

Posts: 16

posted 16 years ago

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Last night I was able to find the following code online which works great in JBoss and Tomcat (same containers I believe), however it will not work with WebLogic. This code wraps the response and buffers it so the calling Servlet can then view the rendered content of the JSP.

The one thing I do notice is that the ByteArrayOutputSteam is not explicity written to... is this handled by JBoss' container implicitly? (I made note of it in the code below lines 52 - 58) If anyone has any ideas, can you let me know...

Thanks

/* ... do stuff in Servlet or Struts Action ... */
 
BufferedHttpResponseWrapper wrapper = new BufferedHttpResponseWrapper(response);
	
ServletContext context = request.getSession().getServletContext();
String url = response.encodeRedirectURL("/email.jsp");
RequestDispatcher dispatcher = context.getRequestDispatcher(url);
 
/* must use include. With forward the RequestDispatcher seems to hold an internal state
   which prevents to do a forward after this to return to the webclient */
dispatcher.include(request, wrapper);
String email = new String(wrapper.getOutput());
System.out.println("email:" + email);
 
/* ... add other stuff like returning something to the webclient ... */
 
-------------------------------
BufferedHttpResponseWrapper source
-------------------------------
 
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
 
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
 
/**
 * This class wraps a HttpServletResponse with a buffered output.
 * You can use this to forward or include a Servlet or JSP page
 * and capture the output from it.
 * 
 * Use getOutput to get the output which was written to the response.
 * Only buffers the Writer. Not the OutputStream !!
 *  
 * @author Joost den Boer
 */
public class BufferedHttpResponseWrapper extends HttpServletResponseWrapper {
 
	PrintWriter writer = null;
	ByteArrayOutputStream baos = null;
 
	/**
	 * Constructor for BufferedHttpResponseWrapper.
	 * Create a new buffered Writer
	 * 
	 * @param response The response object to wrap
	 */
	public BufferedHttpResponseWrapper(HttpServletResponse response) {
		super(response);
               /*

I do not see explicit population of the ByteArrayOutputStream here (I am relearning Streams again, so my logic may be off)

*/
		baos = new ByteArrayOutputStream();
		writer = new PrintWriter(baos);
	}
 
	/**
	 * Return the buffered Writer
	 *  
	 * @see javax.servlet.ServletResponse#getWriter()
	 */
	public PrintWriter getWriter() throws IOException {
		return writer;
	}
 
	/**
	 * Return the output written to the Writer.
	 * To get the output, the Writer must be flushed and closed.
	 * The content is captured by the ByteArrayOutputStream.
	 *  
	 * @return
	 */
	public String getOutput() {
		writer.flush();
		writer.close();
		return baos.toString();
	}
}

Divya Manoj

Greenhorn

Posts: 1

posted 16 years ago

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Hi,

Do you get the content even when the jsp contains struts tags. I am experiencing problems in getting the contents of JSP having the struts tags. What happens is i do get the content but it throws an exception on the browser like ..

=========================================================================

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Stream closed
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:515)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)
org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:99)
jcifs.http.NtlmHttpFilter.doFilter(NtlmHttpFilter.java:147)

root cause

java.io.IOException: Stream closed
org.apache.jasper.runtime.JspWriterImpl.ensureOpen(JspWriterImpl.java:203)
org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:113)
org.apache.jasper.runtime.JspWriterImpl.flush(JspWriterImpl.java:171)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:954)
org.apache.jasper.runtime.PageContextImpl.include(PageContextImpl.java:601)
org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:119)
org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:178)
com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:348)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:221)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:48)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:123)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:186)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:105)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:83)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:207)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:74)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:127)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:107)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:206)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:115)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:143)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:121)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:170)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:123)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:50)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:504)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)
org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:99)
jcifs.http.NtlmHttpFilter.doFilter(NtlmHttpFilter.java:147)

=========================================================================

Could any one help me with this.

Thanks

Dean O'olish

Greenhorn

Posts: 16

posted 16 years ago

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I finally figured out how to get the content of the JSP from my servlet code. I used a ResponseWrapper object. I am running into an issue now though when I try and change the responses content type to "text/plain". The JSP still renders as HTML and not as plain text.

Below is the pseudo code as the real code is at work and I dont have access to it:

The following does not work as the content type is ultimately now changed. The only thing I can think of is that there are other filters (which there are) that are setting the content type. I thought this wouldnt be an issue since I placed my filter at the end of the filter section within the web.xml file. Since the web.xml file calls the filters in the order in which they are placed, I figured my filter would be called last and the response would be able to set the content type.

Does anyone have any ideas on how I might fix this?

- D

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