Plot with servlets

Hi, I have a servlet, and after some input, it gives me a vector of numbers. How can I plot this vector in the web page? What alternatives do I have?

Check out JFreeChart at http://www.jfree.org/jfreechart/. It's super easy to use, although you may want to check the license to avoid conflicts.
Joe

Similar Messages

How to plot with multi colors in a single XY graph?

Hi,
  I'm making hesteresis measurements. In this case, I collect data while sweeping voltage first from 0 to 2V, and then back from 2V to 0V, and the data are plotted in a single XY graph. In the XY graph, I want forward sweep plot of one color while the reverse sweep with another color so I can easily make comparisons. And I want to see the data real time. I tried to wire "plot color" in "property node", but this will change the color globally and can not be applied to a section of data. Can anyone advise me how to do this? Thanks!
Guanglei
Solved!
Go to Solution.

Hi Graham,
  Thank you very much for the reply, I really appreciate it.
  However I don't quite understand your descripton. Yes I do spit my data in two arrays, one for forward sweep, and the other for reverse sweep. I can plot with different colors in XY graph by appending several XY graphs into one, but by doing this I can not see the data real time. I quickly made a vi to demonstrate my problem, hope this will give you a better understanding. Thanks.
Guanglei
Attachments:
demo_GL.vi ‏108 KB

Communicate with servlet after using Java Web Start?

Is it possible to communicate with servlet to get data back and forth
after using Web Start to download the client application?
The demos come with Java Web Start are applications which are
standalone, don't need communicate with the servlet on Web server
after being launched. I am wondering if it is possible, and how (HTTP
& JAX-RPC)?
Thanx in advance.

I've done this using HTTP. I get the server and port from the codebase:
BasicService bs = null;
try {
bs = (BasicService)ServiceManager.lookup("javax.jnlp.BasicService");
String codeBase = bs.getCodeBase().toString();
and use the java.net.HttpURLConnection and java.net.URL classes to send HTTP parameter values to the servlet and to receive results from the HttpURLConnection's input stream.

Displaying *.pdf file on browser with servlet

hi all
this RAMESH,struggling to display a pdf file on browser from a remote mechine
earlier i tried with servlet
response.setContentenType("application/pdf")
out.println();
by this i am getting only some data as below
endobj
4 0 obj
<<
/ProcSet [ /PDF /Text /ImageB ]
/Font << /Fo0 21 0 R /Fo12 24 0 R /Fo13 27 0 R /Fo16 30 0 R /Fo18 33 0 R /Fo19 36 0 R >>
>>
endobj
For this purpose i have gone thru www.lowagie.com
and gone thru all examples but i am not getting how to display on browser or at least awt frame
please requesting all for suggest me some way
tanks all
-Ramesh

are you trying to
a) create a PDF dynamically
b) send an existing PDF

How to use JNI with Servlets

Hi
i was trying to do some example with JNI. I can use JNI with standalone Java application but I just cannot figure out how I can use JNI with Servlet.
Can some one show me a sample code using JNI with Servlets.
thanks very much

hi,
I am also facing the same problem,
when I am using JNI with stand alone application it works fine but when i tried to use it with a servlet It gives unsatisfied linker error
stack: java.lang.UnsatisfiedLinkError: createSocket
     at RelayConnector.createSocket(Native Method)
     at RelayServlet.doGet(RelayServlet.java:70)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at com.iplanet.server.http.servlet.NSServletRunner.invokeServletService(NSServletRunner.java:891)
     at com.iplanet.server.http.servlet.NSServletRunner.Service(NSServletRunner.java:458)
It seems i have to do some path settings in my iplenet web server.
If some one have faced the problem i would be glad to know the solution for this, i am literally bugged up,....

Problem with Servlets

Hi,
I am Tejas , a newbie with servlets. Now, I have a servlet which contains a Javascript method. On clicking a link , the Javascript method is called.
But however, I find that there is some trouble. I created a class called MainFrames.java, the object of which I am instantiating in the Javascript method.
But this code doesnt work properly. I have given the snippet below
out.println("<script type='text/javascript'>");
out.println("function threader()");
out.println("{");
out.println("alert('Inside Threader');");
out.println("<%@ page import=\"XcForm.MainFrames\"%>"); //I have a hunch that this statement is the problem
out.println("<%");
out.println("MainFrames mainframes = new MainFrames();"); //without the import statement above, the MainFrames.java class is not being recognised
out.println("%>");
out.println("}");
out.println("</script>");
Thanks in advance,
Tejas

Do not put presentation code in servlets. Put them in JSPs. And mixing serverside code (scriptlets) and clientside code (javascript) this way is indeed not going to work. That code will certainly not be executed in the order as you write. Serverside code is executed at the server and is finished when the response is completed. So any serverside code inside clientside code is alreay executed. Clientside code is executed at the client and will only execute when the response is completed (onload, etc) or when the client invokes it (onclick, onsubmit, etc). Further on, do not put business code in presentation code. Put them in servlets.

JSF 1.2 with SERVLET 2.3

Hi, i've download the latest JSF 1.2 RI but i can't see any page as i get the following error:
ava.lang.NoSuchMethodError: javax.servlet.http.HttpServletResponse.getContentType()Ljava/lang/String;
at com.sun.faces.context.ExternalContextImpl.getResponseContentType(ExternalContextImpl.java:277)
at com.sun.faces.renderkit.RenderKitImpl.createResponseWriter(RenderKitImpl.java:167)
at com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:87)
at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:222)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:198)
The getContentType method that the exception describes is only available in servlet 2.4 but i'm using a servlet 2.3 only container. Can i use JSF 1.2 with servlet 2.3 ?
Thanks

I'm 90% sure that you cannot. JSF 1.2 is intended to be part of Java EE 5.0. Since Servlets 2.3 are part of J2EE 1.3, I don't think that it will work.
Adam

Some problems with servlet.jar and tomcat 4.1.27

Hello everybody,
I used to work with tomcat 3.3.1 and i've decided to use tomcat 4.1.27 now. The manual explains that we have to change de version of servlet.jar, it's done with servlet-2.3.jar but on tomcat starting i have this message:
jar not loaded. See servlet spec [...]. Offending class: javax/servlet/Servlet.class
what can i do, i've red all de documentation and i think all versions a OK??
thanks per advance
antoine

I am running Tomcat 4.1.18, so your configuration may be slightly different. I found the Servlet.class file you are missing residing in the Tomcat/common/lib directory in the Servlet.jar file. Check your path and also make sure your Servlet.jar file contains the missing class.

Polar plot with legend points

I can put one Polar Plot with legend in points?
Case:
I have magnitude and phase arrays for build polar plot and i want put rotation legend in each point of measurement. Then we have 3 arrays (magnitude, phase and rotation), but rotation need stay like legend for each point.
Somebody already do it?
thx for tip.
Leonardo de S. Cavadas
Maintenance Engineer and Inspection - Bureau Veritas do Brasil
Engineer Metallurgist with emphasis in Advanced Materials
Technologist in Computer Science

Unclebump,
i do one simple modification to be possible add rotation value to image, isn't better solution but i think that i'm near to solution way. Look these VIs, Re-link is necessary.
Leonardo de S. Cavadas
Maintenance Engineer and Inspection - Bureau Veritas do Brasil
Engineer Metallurgist with emphasis in Advanced Materials
Technologist in Computer Science
Attachments:
Plot Polar Data with Legend.vi ‏74 KB
OtherPolarPlot.vi ‏67 KB
Polar Plot with Legend.vi ‏75 KB

Communicating with Servlets....

hi!
Wat are all the different ways in which the JSP used to communicate with Servlet?
Thanx,
Rgds,
Sasi

Jsp page communication with Servlets....
web.xml -- Servlets loaded during application startup
struts config -- Servlet mapping (w.r.t struts).
and u can import servlets in jsp and can use it... there are so many possible ways of using servlets coz jsp pages inturn convert into servlets and got executed.....

Forward with servlets

Im using tomcat 4.06 and i have some problems with servlets and forwarding:
This is my servlet:
import java.io.PrintWriter;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
public class NTenant extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
String email = request.getParameter("tenant");
//insert new tenant into database.
System.out.println("Redirigiendo");
ServletContext sc = getServletConfig().getServletContext();
RequestDispatcher rdNext = sc.getRequestDispatcher("/tenantForm.html");
rdNext.forward(request, response);
System.out.println("Redirigido");
I get this error:
type Status report
message Servlet invoker is currently unavailable
description The requested service (Servlet invoker is currently unavailable) is not currently available.
This is my dir structure:
webapps\form\NewTenant.html
webapps\form\tenantForm.html
webapps\form\WEB-INF\web.xml
webapps\form\WEB-INF\classes\NTenant.class
webapps\form\WEB-INF\classes\TenantServlet.class
The problem is that i cannot find my html, what must i write here? sc.getRequestDispatcher("/tenantForm.html"); <-----
Thank you very much

I heve tried with "../tenantForm.html"
java.lang.IllegalArgumentException: Path ../tenantForm.html does not start with a "/" character
     at org.apache.catalina.core.ApplicationContext.getRequestDispatcher(ApplicationContext.java:572)
     at org.apache.catalina.core.ApplicationContextFacade.getRequestDispatcher(ApplicationContextFacade.java:174)
     at NTenant.doPost(NTenant.java:19)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
Now Im trying with:
RequestDispatcher rdNext = sc.getRequestDispatcher "/../tenantForm.html");
And I got:
type Exception report
message Internal Server Error
description The server encountered an internal error (Internal Server Error) that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
     at NTenant.doPost(NTenant.java:20)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:465)
     at org.apache.catalina.servlets.InvokerServlet.doPost(InvokerServlet.java:216)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:190)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
     at org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:246)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
     at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2347)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
     at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
     at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:468)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
     at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
     at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:1027)
     at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1125)
     at java.lang.Thread.run(Thread.java:536)
Any other idea?

Dialogs with servlets

Hi
Does anyone know how to use dialogs with servlets? I'd like to show a confirm dialog on the client machine. My first idea was to use JOptionPane.showConfirmDialog as such in the servlet, but then of course de dialog pops-up on the server side, and not on client side.
Many thanks for the help,
Nic

You need to use javascript to confirm, ask questions, etc...
You can see :
http://www.webreference.com/programming/javascript/confirm/
Or
http://www.bodo.com/javacool.htm
Fred

Swings with servlets

Hi,
how we can use swings with servlets or jsps.
or
how we can display the browser in the swings.
please give me a valid answer with examples.

Hi,
Your question is not clear... are you trying to display HTML using swing components or are you trying to use swing in a server-side application?
Some Swing components (e.g. JLabel) natively support simple html, so:
JLabel lbl = new JLabel("<html>hello <b>world</b></html>");would result in a JLabel that looks with the word "world" in bold. If you need also frames, css and javascript support - you'll need to reach for a 3^rd^ party library, I'm afraid.
As for using swing in servers, look at this article:
http://today.java.net/pub/a/today/2006/04/20/bringing-swing-to-the-web.html
If you meant neither, please explain more.
Hope this helps, though.
Michael Bar-Sinai

[Help] To prevent timeout error of browser in clinet with servlet in server

Hi all,
If a browser (for example, Internet Explorer) do not get any response from a server for more than sometime (in case of IE, default is 5 min), it will stop waiting and return some timeout error message.
But I have a servlet, which has a really long-time(at least 10 min) job to do before it could send a response to the browser. So, before the browser in client can get the result, it stops waiting.
I know I can change the time-out setting of browser in client machines, but there are hundred of thousands.
So, what I am asking is if it is possible to do it with servlet in server, and how?
(for example, send something to the client every few minutes, but I do not know how to do it .)
thanks a lot!

What you would have to do is set up some sort of 'Buffer' servlet.
It starts the job in the background, and then returns a page saying job started - client does not time out.
You would have to start it in a seperate process - probably a new Thread.
The client would then have to send back requests asking - is it finished yet?
While the job is not finished the buffer servlet returns a "not yet" message.
On completion, the job can be sent back to the client.
Couple of pointers:
It may be easier to have the background process generate the result to file - then your buffer servlet can just pick up the file when it is completed.
To get your page to refresh multiple times, you can use javascript: window.setTimeout("[reload page]");
Good luck,
evnafets

Help with servlet

I have a project with servlets in the 2 following folders
myprojects and myclasses
In my projects I have the helloProject and inside it I have the helloHtml folder and the helloPackage.
So in the helloHtml folder I have the hello.html file and in the helloPackage I have the Hello.java (which is the servlet)
when I compile this .java file the class file is inserted in the file myclasses\helloProject\helloPackage
First in the file hello.html I have the code
action="http://localhost:8080/servlet/helloPackage.Hello
and so the servlet is executed fine.
The problem is that I need to put a button in the code of Hello.java
so that I can have reloaded the first page which is the hello.html
But I am confused if I write onclick=history.go(-1) I have what I want but this page is not reloaded so I have some parameters there that I do not want
Can I write sth like onclick=location.href=http://locahost:8080/.....??
Could you please give me an advice considering the above description of my files??
Thank tou very much....

use sendRedircet(String AbsoluteURL) to send the Browser a redirect header so the browser send a new (fresh) request to the serlvet (with any parameter you specified).

Plot with servlets

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