Deal with the errors : Errors « JSP « Java
Deal with the errors
// generateError.jsp
<%@ page errorPage="processError.jsp" %>
<%-- Declare the page to send errors to --%>
<%-- After clicking the button, it will call itself again the generate error --%>
<%-- This scriptlet checks a hidden field to see whether or not to throw an exception --%>
<%
String hiddenField = request.getParameter("hiddenValue");
if ( hiddenField.equals("error"))
throw new java.lang.NullPointerException();
%>
<HTML>
<HEAD><TITLE>Generate Error</TITLE></HEAD>
<BODY>
This page generates an error when you click the button.<P>
<FORM METHOD="POST" ACTION="generateError.jsp">
<INPUT TYPE="HIDDEN" NAME="hiddenValue" VALUE="error">
<INPUT TYPE="SUBMIT" VALUE="Generate exception!">
</FORM>
</BODY>
</HTML>
//Another JSP file: processError.jsp
<%@ page isErrorPage="true" %>
<HTML>
<HEAD><TITLE> Process Error</TITLE></HEAD>
<BODY>
<% if ( exception != null ) {
out.write("\nAn error occurred. This page is to tell you what you did wrong.\n");
}
else {
out.write("\nYou have reached this page, but no error information is available.\n");
}
%>
</BODY>
</HTML>
