Servlet Filter - Reading Request Error

Question

I have a servlet filter that sits in front of a webservice servlet (AXIS) - what I want the filter to do is to look at the content of the ServletRequest and if a particular string is located in the request, I want to call another service. Everything works just fine except (isin't there always an execept) that when I execute the following code in the filter:
BufferedReader inReader = request.getReader();
String line = null;
StringBuffer sbuf = new StringBuffer();
// Read the current request into a buffer
while((line = inReader.readLine()) != null) {
sbuf.append(line);
sbuf.append("\n\r");
if (sbuf.toString().indexOf("mystring") > -1) {
// I do some code
} else {
chain.doFilter(request, wrapper);
When I execute this code, at the chain.doFilter I get an "java.lang.IllegalStateException: getReader() has already been called for this request"
I know that this is because I obtained the Reader from the request. But my question is - How can I look at the request string so that I can evaluate it and not have this exception thrown..
Thx in advance...

Answer 1

My guess is that when you do the chain.doFilter you pass the request to another resource that then tries to access the request.getInputStream method.
From the JavaDocs:
getReader
public java.io.BufferedReader getReader()
throws java.io.IOException
Retrieves the body of the request as character data using a BufferedReader. The reader translates the character data according to the character encoding used on the body. Either this method or getInputStream() may be called to read the body, not both.
Returns:
a BufferedReader containing the body of the request
Throws:
java.io.UnsupportedEncodingException - if the character set encoding used is not supported and the text cannot be decoded
IllegalStateException - if getInputStream() method has been called on this request
java.io.IOException - if an input or output exception occurred