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