I am new to web programming. I am using this simple code in my get method
response.setContentType( "text/html" );
PrintWriter out = response.getWriter();
out.println( "<html><head><title>Guest Book</title></head><body>" );
out.println(" </body></html> ");
I am getting the below error while clicking on run on server
enter image description here
Note: When i removed the html code, the servlet is working fine.Is it my Html code problem or any tomcat sevrver issue.
The servlet is in my package cs3220homework and servlet name is #WebServlet("/MainFolder").
I tried everywhere to look for the issue and i was not able to find it.If its duplicate please let me know.
Thanks for your reply
Harminder
Its working fine. App is named Test and Servlet class is also named Test. This is the url http://localhost:8080/Test/Test
package foo;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/Test")
public class Test extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType( "text/html" );
PrintWriter out = response.getWriter();
out.println( "<html><head><title>Guest Book</title></head><body>" );
out.println(" </body></html> ");
}
}
Related
I need verify header before receive the request. I found that tomcat valve can help in it. I follow these steps but valve is not called:
make a maven project and do this code in it.
package cz.ValveTest;
import java.io.IOException;
import java.util.Enumeration;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.valves.ValveBase;
public class ProcessingValve extends ValveBase {
private static final Logger logger = Logger.getLogger(ProcessingValve.class.getName());
#Override
public void invoke(Request request, Response response) throws IOException,
ServletException {
HttpServletRequest httpServletRequest = request.getRequest();
Enumeration<String> headerNames = httpServletRequest.getHeaderNames();
logger.info("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
while (headerNames.hasMoreElements()) {
String header = headerNames.nextElement();
logger.log(Level.INFO, "Header --> {0} Value --> {1}", new Object[]{header, httpServletRequest.getHeader(header)});
}
getNext().invoke(request, response);
}
}
make jar and put jar inside tomcat/lib folder
add this line in server.xml
<valve className="cz.ValveTest.ProcessingValve"/>
restart tomcat.
Now I hit my web service with header:
Expect : 100-continue
but using this configuration and code valve is not called on http hit.If any one knew why tomcat valve is not called please help.
The tags in server.xml are case sensitive.
So try this :
<Valve className="cz.ValveTest.ProcessingValve"/>
I have a folder that has only .java files. There are no .html, .jsp, .jsf etc. files only .java. I was told that this is a web application, but I have no idea on how to run it.
Here is a sample code from one of the .java files:
public List<String> generateHtml(String name, String css) {
List<String> html = new ArrayList<>();
html.add("<!DOCTYPE HTML><html><head><link rel=\"stylesheet\" type=\"text/css\" href=\"" + css
+ "\"/></head><body>");
html.add("<div class='screen page_size " + name + "'>");
for (HtmlElement element : orderedElements) {
element.generateHtml(html);
}
html.add("</div>");
html.add("</body></html>");
return html;
}
I tried making a web project in eclipse and importing the files and running it, but no luck. It gives me a lot of errors with something to do with jetty. After installing jetty it still didnt work. Maybe I am installing it wrong. Anyone has any idea?
If you want to create a runnable war with jetty, have a look a the Embedded Jetty examples
You can call the generateHtml method from the servlet below.
package org.eclipse.jetty.embedded;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletHandler;
public class MinimalServlets
{
public static void main( String[] args ) throws Exception
{
Server server = new Server(8080);
ServletHandler handler = new ServletHandler();
server.setHandler(handler);
handler.addServletWithMapping(HelloServlet.class, "/*");
server.start();
server.join();
}
#SuppressWarnings("serial")
public static class HelloServlet extends HttpServlet
{
#Override
protected void doGet( HttpServletRequest request,
HttpServletResponse response ) throws ServletException,
IOException
{
response.setContentType("text/html");
response.setStatus(HttpServletResponse.SC_OK);
//From here you can call the generateHtml method
response.getWriter().println("<h1>Hello from HelloServlet</h1>");
}
}
}
Among the COMET,SOCKETS,SSE i felt server sent events is easy to implement.
And i am using tomcat server so i used servlets to implement SSE.
But i am facing big problem here and searched a lot but i did not got any solution to it.
The problem is if you see the basic example at sever sent event
The output is repeating for every 4-seconds,can't we make it to change output in same line.
In detail:
After 4 seconds a new updated result is printing in next line of previous output,
i want it to be printed in the same line of previous output(over write on previous output) and it should looks like a digital watch.
And my servlet code is like this what kind of changes i have to do.
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#WebServlet("/SseServer")
public class SseServer extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/event-stream;charset=UTF-8");
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Connection", "keep-alive");
PrintWriter out = response.getWriter();
while (true) {
out.print("id: " + "ServerTime" + "\n");
out.print("data: " + new Date().toLocaleString() + "\n\n");
out.flush();
try {
Thread.currentThread().sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
I thought using while loop make it as a repeated result.
GREAT THANKS FOR ANY HELP
The example you linked to uses the following code:
document.getElementById("result").innerHTML += event.data + "<br>";
So, it appends the new event data to the content of the result element. To replace it, just change it to
document.getElementById("result").innerHTML = event.data + "<br>";
In short, your question doesn't have anything to do with how you produce the event at server-side, but everything to do with how you consume the event, in the browser.
For my use, I created a PDF file using flying-saucer library. It was a legacy HTML so I cleaned out the XHTML using HTMLCleaner library.
After this I serialize the XML as string then pass it to the iText module of flying-saucer to render it and subsequently create the PDF.
This PDF I place it in the OutputStream. After the response is committed I get a dialog asking to save or open it. However it does not get saved as PDF file. I have to right-click and open it in Adobe or any PDF reader.
How do I make it display in the PDF reader. And make the file be saved as .pdf file. What would be an effective and user-friendly way to handle this issue? Help as always will be greatly appreciated!
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.StringBufferInputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.htmlcleaner.CleanerProperties;
import org.htmlcleaner.DomSerializer;
import org.htmlcleaner.HtmlCleaner;
import org.htmlcleaner.PrettyXmlSerializer;
import org.htmlcleaner.TagNode;
import org.htmlcleaner.XmlSerializer;
import org.w3c.dom.Document;
import org.xhtmlrenderer.pdf.ITextRenderer;
import org.xhtmlrenderer.resource.XMLResource;
public class MyPDF extends HttpServlet {
public MyPDF() {
super();
}
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/pdf");
String html = request.getParameter("source");
try
{
HtmlCleaner cleaner = new HtmlCleaner();
CleanerProperties props = cleaner.getProperties();
TagNode node = cleaner.clean(html);
//String content = "<" + node.getName() + ">" + cleaner.getInnerHtml(node) + "</" + node.getName() + ">";
//System.out.println("content " +content);
OutputStream os = response.getOutputStream();
System.out.println("encoding " +response.getCharacterEncoding());
final XmlSerializer xmlSerializer = new PrettyXmlSerializer(props);
final String html1 = xmlSerializer.getAsString(node);
ITextRenderer renderer = new ITextRenderer();
renderer.setDocumentFromString(html1);
renderer.layout();
renderer.createPDF(os);
os.close();
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
public void init() throws ServletException {
}
}
Your MIME type is incorrect for PDF. It should be application/pdf.
Change
response.setContentType("text/pdf");
to
response.setContentType("application/pdf");
See https://www.rfc-editor.org/rfc/rfc3778 for the RFC for the PDF MIME type.
Edit: Totally overlooked the "Save as .pdf" question.
You'll also need to add something like:
response.setHeader("content-disposition", "attachment; filename=yourFileName.pdf");
to tell the browser what the default file name should be.
I am a newbie for servlet applications, trying to learn the subject. On my way, I wrote a servlet class called FormWebServlet that uses the org.apache.http.impl.client.DefaultHttpClient class. However, I get the exception
java.lang.ClassNotFoundException: org.apache.http.impl.client.DefaultHttpClient
... that clearly shows that this class does not exist, although I have added the jar file to the project.
The server returns an "HTTP Status 500" error with the message that the "root cause" is this missing class:
java.lang.NoClassDefFoundError: org/apache/http/impl/client/DefaultHttpClient
testPackage.FormWebServlet.doGet(FormWebServlet.java:45)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
TRIES
1) I searched for the missing jar file and added it to the project (by going on the project in "Eclipse JAVA EE IDE for Web Developers, 20100917-0705"'s project explorer, select "Properties", selected the "Java Build Path" and clicked the [Add External JARs...] button.) The added jar file is from the Apache site and is called httpclient-4.1.1.jar.
2) As I still get the same error, I extracted with 7-ZIP the DefaultHttpClient.class file and put it into the WebContent/WEB-INF/lib directory.
QUESTION
What am I doing wrong? Neither of the other two JAR files do contain the class, nor is there a class with this name in the WEB-INF/lib folder.
DETAILS
Inculded JARs:
common-httpclient-3.0.1.jar
httpclient-4.1.1.jar
httpcore-4.1.jar
FormWebServlet.jar:
/**
*
*/
package testPackage;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import coreServlets.ServletUtilities;
/**
*
*/
#WebServlet(description = "Gets the book's barcode with a form", urlPatterns = { "/FormWebServlet" })
public class FormWebServlet extends HttpServlet {
/** */
private static final long serialVersionUID = 6008315960327824633L;
/**
* #see HttpServlet#doGet(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doGet(final HttpServletRequest request,
final HttpServletResponse response)
throws IOException, ServletException {
final String BAR_CODE = request.getParameter("barCode");
response.setContentType("text/html");
final PrintWriter out = response.getWriter();
if (BAR_CODE != null) {
HttpClient client = new DefaultHttpClient();
final String ADDRESS = ServletUtilities.getHttpAddress(BAR_CODE);
out.println("ADDRESS = \"" + ADDRESS + '\"');
HttpGet get = new HttpGet(ADDRESS);
HttpResponse httpResponse = null;
// Removed commented code that will use these objects
}
}
}
Just put the JAR files themselves into WEB-INF/lib, not the class file. That way they will be included in your deployment.