All about Alan Campbell

How do I send XML message in POST body

I managed to get it to work by creating a wrapper around the request object and modifying the values that way. I got the idea from another post in this forum.

I have posted the code below in case anyone else is looking to do something similar (sorry if its a bit of a long post).

This is my HTML page:-

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
<LINK href="theme/Master.css" rel="stylesheet" type="text/css">
<TITLE>WMB Proxy Servlet Test Message Poster</TITLE>
</HEAD>
<FORM METHOD="POST" ACTION="/ServletTest/ServletTest">
<table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="AutoNumber1">
<tr>
<td width="150%" align="center" colspan="3"><b>
<font face="Verdana" size="5">Servlet Test</font></b></td>
</tr>
<tr>
<td width="16%" align="left"> </td>
<td width="134%" align="left" colspan="2"> </td>
</tr>
<tr>
<td width="16%" align="left"><font face="Verdana" size="2">Servlet</font></td>
<td width="134%" align="left" colspan="2"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ServletName" size="94"></font></td>
</tr>
<tr>
<td width="16%" align="left"> </td>
<td width="38%" align="left"> </td>
<td width="96%" align="left"> </td>
</tr>
<tr>
<td width="16%" align="left"> </td>
<td width="38%" align="left"><font face="Verdana" size="2">Name</font></td>
<td width="96%" align="left"><font face="Verdana" size="2">Value</font></td>
</tr>
<tr>
<td width="16%" align="left"><font face="Verdana" size="2">Parameter 1</font></td>
<td width="38%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamName1" size="33"></font></td>
<td width="96%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamValue1" size="57"></font></td>
</tr>
<tr>
<td width="16%" align="left"><font face="Verdana" size="2">Parameter 2</font></td>
<td width="38%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamName2" size="33"></font></td>
<td width="96%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamValue2" size="57"></font></td>
</tr>
<tr>
<td width="16%" align="left"><font face="Verdana" size="2">Parameter 3</font></td>
<td width="38%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamName3" size="33"></font></td>
<td width="96%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamValue3" size="57"></font></td>
</tr>
<tr>
<td width="16%" align="left"><font face="Verdana" size="2">Parameter 4</font></td>
<td width="38%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamName4" size="33"></font></td>
<td width="96%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamValue4" size="57"></font></td>
</tr>
<tr>
<td width="16%" align="left"><font face="Verdana" size="2">Parameter 5</font></td>
<td width="38%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamName5" size="33"></font></td>
<td width="96%" align="left"><font face="Verdana">
<INPUT TYPE="TEXT" NAME="ParamValue5" size="57"></font></td>
</tr>
</table>
<P>
 <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="AutoNumber2">
<tr>
<td width="16%">
<p align="left"><font face="Verdana" size="2">Test message</font></td>
<td width="84%">
<p align="left">
<font face="Verdana">
<TEXTAREA NAME="TestMessage" ROWS=17 COLS=90>
</TEXTAREA></font></td>
</tr>
</table>
<P align="left">
<font face="Verdana">
<INPUT TYPE=SUBMIT NAME="SendTest" VALUE="Send Test"><font size="2"> </font>
</font>
</FORM>
</BODY>
</HTML>

This is my servlet code:-

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class ServletTest extends HttpServlet implements Servlet {
public ServletTest() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
RequestDispatcher dispatcher = null;
ServletTestReqWrapper requestWrapper = null;
String paramTestMessage = null;
String extServlet = null;
String extServletContext = null;
String extServletName = null;
StringBuffer parameterStringBuffer = new StringBuffer();
String parameterName = null;
String parameterValue = null;
int seperatorPos = 0;
int loopCounter = 0;
// Get the name of the servlet, including its context
extServlet = request.getParameter("ServletName");
if (extServlet == null) {
throw new ServletException("Servlet parameter not found");
}
seperatorPos = extServlet.indexOf('/');
if (seperatorPos == -1) {
throw new ServletException("Invalid servlet name - it must start with /");
} else {
seperatorPos = extServlet.indexOf('/', (seperatorPos + 1));
if (seperatorPos == -1) {
throw new ServletException("Invalid servlet name - it must be conext/servlet");
}
}
extServletContext = extServlet.substring(0, seperatorPos);
extServletName = extServlet.substring(seperatorPos);
// Get each of the parameters (max of 5) and build a parameter string.
for (loopCounter = 0; loopCounter < 6; loopCounter = loopCounter + 1) {
parameterName = request.getParameter(("ParamName" + loopCounter));
if (parameterName != null) {
if (parameterName.length() > 0) {
parameterValue = request.getParameter(("ParamValue" + loopCounter));
if (parameterValue != null) {
if (parameterStringBuffer.length() > 0) {
parameterStringBuffer.append("&");
}
parameterStringBuffer.append(parameterName);
parameterStringBuffer.append("=");
parameterStringBuffer.append(parameterValue);
}
}
}
}
// Get the test message.
paramTestMessage = request.getParameter("TestMessage");
// Create a request wrapper so that we can modify the values of the
// request object.
HttpServletRequest httpServletRequest = (HttpServletRequest)request;
try {
requestWrapper = new ServletTestReqWrapper(httpServletRequest);
} catch (IOException ex) {
throw new ServletException("Unable to create request wrapper", ex);
}
// Override these values in the wrapper request.
requestWrapper.setPayload(paramTestMessage);
requestWrapper.setQueryString(parameterStringBuffer.toString());
// Get our local context.
ServletContext context = getServletContext();
if (context == null) {
throw new ServletException("Cannot get local context");
}
// get the context of the external servlet.
ServletContext externalContext = context.getContext(extServletContext);
if (externalContext == null) {
throw new ServletException("Cannot get external context");
} else {
// Get the dispatcher for the external context
dispatcher = externalContext.getRequestDispatcher(extServletName);
if (dispatcher == null) {
throw new ServletException("Cannot get dispatcher");
}
}
// Forward this new wrapper request to the external servlet.
dispatcher.forward(requestWrapper, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}

And this is my wrapper code:-

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ServletTestReqWrapper extends HttpServletRequestWrapper {
private String wrapperXmlPayload;
private String wrapperQueryString;
public ServletTestReqWrapper (HttpServletRequest request) throws IOException {
super(request);
// read the original payload into the xmlPayload variable
StringBuffer stringBuffer = new StringBuffer();
BufferedReader bufferedReader = null;
try {
// read the payload into the StringBuilder
InputStream inputStream = request.getInputStream();
if (inputStream != null) {
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
char[] charBuffer = new char[128];
int bytesRead = -1;
while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
stringBuffer.append(charBuffer, 0, bytesRead);
}
} else {
// make an empty string because there is no payload
stringBuffer.append("");
}
} catch (IOException ex) {
throw ex;
} finally {
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException iox) {
// ignore
}
}
}
wrapperXmlPayload = stringBuffer.toString();
wrapperQueryString = request.getQueryString();
}
/**
* Override of the getInputStream() method which returns an InputStream that reads from the
* stored XML payload string instead of from the request's actual InputStream.
*/
//@Override
public ServletInputStream getInputStream () throws IOException {
final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(wrapperXmlPayload.getBytes());
ServletInputStream inputStream = new ServletInputStream() {
public int read () throws IOException {
return byteArrayInputStream.read();
}
};
return inputStream;
}
/**
* Override of the getQueryString() method to return the value in the local variable.
*/
public String getQueryString() {
return wrapperQueryString;
}
/**
* New setPayload() method which sets the local variables value.
*/
public boolean setPayload(String newPayload) throws ServletException {
wrapperXmlPayload = newPayload;
return true;
}
/**
* New setQueryString() method which sets the local variables value.
*/
public boolean setQueryString(String newQueryString) throws ServletException {
wrapperQueryString = newQueryString;
return true;
}
}

16 years ago

Servlets

How do I send XML message in POST body

Originally posted by Paul Clapham:
There's been a lot of conversation since you posted this but I'm surprised you haven't realized that the answer is:

YES.

There may have been a lot of conversation but no one actually said that I could or couldnt do it. I just wanted clarification.

Thank you both for your time and patience.

Alan

16 years ago

Servlets

How do I send XML message in POST body

Originally posted by Bear Bibeault:
Will it always be true that they apps reside in the same instance? A forward, even a cross-context forward cannot span servers.

Yes, this will always be the case.

In any case, it's moot here because you need to generate a new request to satisfy the expected requirements of the web service.

So, does that mean that its not possible to create a new request object?
[ November 26, 2008: Message edited by: Alan Campbell ]

16 years ago

Servlets

How do I send XML message in POST body

Originally posted by Bear Bibeault:
What's the relationship between the sender and receiver? If they're not in the same web application, a forward is out of the question.

If the receiving server is remote, you need to create a new request to it. How could it possibly have anything to do with the current request on a different server?

Really? I have to admit, I am new to working with servlets (been doing it 3 days now!), but the code that I posted above (the MBProxyTest servlet) calls the DisplayParameters servlet. Both of these servlets run on the same server and in the same instance of Tomcat, but in different contexts ( had to switch this on in Tomcat, by default it was disabled - crossContext=true). They are seperate web applications. It works in that MBProxyTest can successfully forward to DisplayParameters, which displays the parameters that were entered in the HTML form.
[ November 26, 2008: Message edited by: Alan Campbell ]

16 years ago

Servlets

How do I send XML message in POST body

Thanks for replying.

I had thought about creating a new connection but thought that using forward (servlet to servlet) might be more efficient from a connectivity point of view (not having to go through the tcp/ip, http connectiong 'thing').

I am rapidly coming to the conclusion it is not possible to create a new request object 'on the fly' and that the only way would be to create a brand new connection. Is this a correct conclusion?

Alan

16 years ago

Servlets

How do I send XML message in POST body

Hi,

I am trying to write a test web page with associated servlet (running in Tomcat) to send a test message to a third part servlet (also running in Tomcat).

The third party servlet expects a request in the following format:-

I have written a HTML page that will allow the tester to put in up to 5 parameters (name and value) put a XML message:-

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
<LINK href="theme/Master.css" rel="stylesheet" type="text/css">
<TITLE>WMB Proxy Servlet Test Message Poster</TITLE>
</HEAD>
<FORM METHOD="POST" ACTION="/MBProxyTest/MBProxyTest">
<table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="AutoNumber1">
<tr>
<td width="16%"> </td>
<td width="38%">Name</td>
<td width="96%">Value</td>
</tr>
<tr>
<td width="16%">Parameter 1</td>
<td width="38%"><INPUT TYPE="TEXT" NAME="ParamName1"></td>
<td width="96%"><INPUT TYPE="TEXT" NAME="ParamValue1"></td>
</tr>
<tr>
<td width="16%">Parameter 2</td>
<td width="38%"><INPUT TYPE="TEXT" NAME="ParamName2"></td>
<td width="96%"><INPUT TYPE="TEXT" NAME="ParamValue2"></td>
</tr>
<tr>
<td width="16%">Parameter 3</td>
<td width="38%"><INPUT TYPE="TEXT" NAME="ParamName3"></td>
<td width="96%"><INPUT TYPE="TEXT" NAME="ParamValue3"></td>
</tr>
<tr>
<td width="16%">Parameter 4</td>
<td width="38%"><INPUT TYPE="TEXT" NAME="ParamName4"></td>
<td width="96%"><INPUT TYPE="TEXT" NAME="ParamValue4"></td>
</tr>
<tr>
<td width="16%">Parameter 5</td>
<td width="38%"><INPUT TYPE="TEXT" NAME="ParamName5"></td>
<td width="96%"><INPUT TYPE="TEXT" NAME="ParamValue5"></td>
</tr>
</table>
<P>
 <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="AutoNumber2">
<tr>
<td width="50%">Test message</td>
<td width="50%">
<TEXTAREA NAME="TestMessage" ROWS=5 COLS=60>
</TEXTAREA></td>
</tr>
</table>
<P>
<INPUT TYPE=SUBMIT NAME="SendTest" VALUE="Send Test">
</FORM>
</BODY>
</HTML>

When the form posts to the servlet, all of the parameters are specified in the body, which isnt what the third party servlet wants. So, I placed my own servlet in the path MBProxyTest which could take the request and rebuild it in the correct format and forward it to the third party servlet.

import java.io.IOException;
import javax.servlet.Servlet;
import javax.servlet.ServletContext;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
public class MBProxyTest extends HttpServlet implements Servlet {
public MBProxyTest() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
boolean useLocalContext = false;
RequestDispatcher dispatcher = null;
HttpServletRequest newRequest = null;
HttpServletResponse newResponse = null;
PrintWriter out = response.getWriter();
ServletContext context = getServletContext();
if (context == null) {
out.println("ERROR:Cannot get local context\n");
}
ServletContext externalContext = context.getContext("/DisplayParameters");
if (externalContext == null) {
out.println("ERROR:Cannot get external context\n");
} else {
dispatcher = externalContext.getRequestDispatcher("/DisplayParameters");
if (dispatcher == null) {
out.println("ERROR:Cannot get dispatcher\n");
}
}
dispatcher.forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}

The problem is that I cant work out how to create a new request so that I can pass the correctly formated message to the third party servlet.

Any suggestions?

Alan

16 years ago

Servlets

Alan Campbell

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