The following example shows how to implement a filter:
package com.ibm.websphere;
import java.io.*;
import javax.servlet.*;
public class LoggingFilter implements Filter
{
File _loggingFile = null;
// implement the required init method
public void init(FilterConfig fc)
{
// create the logging file
xxx;
}
// implement the required doFilter method...this is where most of
the work is done
public void doFilter(ServletRequest request,
ServletResponse response, FilterChain chain)
{
try
{
// add request info to the log file
synchronized(_loggingFile)
{
xxx;
}
// pass the request on to the next resource in the chain
chain.doFilter(request, response);
}
catch (Throwable t)
{
// handle problem...
}
}
// implement the required destroy method
public void destroy()
{
// make sure logging file is closed
_loggingFile.close();
}
}