Mega Code Archive
Servlet exception handler
<![CDATA[
package com.ack.web.servlet;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Map the location of the servlet to handle at error
* with the supplied status code
*
<web-app>
...
<error-page>
<exception-type>javax.servlet.ServletException</exception-type>
<location>/servlet/com.ack.web.servlet.ServletExceptionHandler</location>
</error-page>
</web-app>
*/
public class ServletExceptionHandler extends HttpServlet {
public void doGet( HttpServletRequest req, HttpServletResponse res )
throws ServletException, IOException {
res.setContentType( "text/html" );
PrintWriter pw = res.getWriter();
String exceptionType = getRequestAttribute( req,
"javax.servlet.error.exception_type",
"status code not supplied" );
String errorMsg = getRequestAttribute( req,
"javax.servlet.error.message",
"error msg not supplied" );
// exception attribute available as of servlet 2.3 API
Object exception = req.getAttribute( "javax.servlet.error.exception" );
pw.println( "<h1>Custom Exception Handler</h1>" );
pw.println( "<h2>Exception type: " + exceptionType + "</h1>" );
pw.println( "<h2>Exception Message: " + errorMsg + "</h1>" );
pw.println( "<p>Problem accessing: " + req.getRequestURI() + "</p>" );
// if we have the exception dump it out to the page
if( exception != null ) {
ByteArrayOutputStream bos = null;
try {
pw.println( "<p><hr noshade><p><pre>" );
bos = new ByteArrayOutputStream();
PrintWriter writer = new PrintWriter( bos, true );
( (Exception) exception ).printStackTrace( writer );
pw.println( bos.toString() );
}
finally {
pw.println( "</pre>" );
if( bos != null ) bos.close();
}
}
// output date and time of error
pw.println( "<p><hr><p>" );
pw.println( new java.util.Date( System.currentTimeMillis() ) );
}
private String getRequestAttribute( HttpServletRequest req,
String name,
String defaultValue ) {
Object value = req.getAttribute( name );
return ( value != null ) ? value.toString() : defaultValue;
}
}
]]>