org.apache.struts.action
Class ExceptionHandler

java.lang.Object
  org.apache.struts.action.ExceptionHandler

public class ExceptionHandler
extends Object

An ExceptionHandler is configured in the Struts configuration file to handle a specific type of exception thrown by an Action.execute method.

Since:

Struts 1.1

Field Summary

static String	INCLUDE_PATH The name of a configuration property which can be set to specify an alternative path which should be used when the HttpServletResponse has already been committed.
static String	SILENT_IF_COMMITTED The name of a configuration property which indicates that Struts should do nothing if the response has already been committed.

Constructor Summary

ExceptionHandler()

Method Summary

protected String	determineIncludePath(ExceptionConfig config, ActionForward actionForward) Return a path to which an include should be attempted in the case when the response was committed before the ExceptionHandler was invoked.
ActionForward	execute(Exception ex, ExceptionConfig ae, ActionMapping mapping, ActionForm formInstance, HttpServletRequest request, HttpServletResponse response) Handle the Exception.
protected void	handleCommittedResponse(Exception ex, ExceptionConfig config, ActionMapping mapping, ActionForm formInstance, HttpServletRequest request, HttpServletResponse response, ActionForward actionForward) Attempt to give good information when the response has already been committed when the exception was thrown.
protected void	logException(Exception e) Logs the Exception using commons-logging.
protected void	storeException(HttpServletRequest request, String property, ActionMessage error, ActionForward forward, String scope) Default implementation for handling an ActionMessage generated from an Exception during Action delegation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INCLUDE_PATH

public static final String INCLUDE_PATH

The name of a configuration property which can be set to specify an alternative path which should be used when the HttpServletResponse has already been committed.

To use this, in your struts-config.xml specify the exception handler like this:

   <exception
       key="GlobalExceptionHandler.default"
       type="java.lang.Exception"
       path="/ErrorPage.jsp">
       <set-property key="INCLUDE_PATH" value="/error.jsp" />
   </exception>
  

You would want to use this when your normal ExceptionHandler path is a Tiles definition or otherwise unsuitable for use in an include context. If you do not use this, and you do not specify "SILENT_IF_COMMITTED" then the ExceptionHandler will attempt to forward to the same path which would be used in normal circumstances, specified using the "path" attribute in the <exception> element.

Since:

Struts 1.3

See Also:

Constant Field Values

SILENT_IF_COMMITTED

public static final String SILENT_IF_COMMITTED

The name of a configuration property which indicates that Struts should do nothing if the response has already been committed. This suppresses the default behavior, which is to use an "include" rather than a "forward" in this case in hopes of providing some meaningful information to the browser.

To use this, in your struts-config.xml specify the exception handler like this:

   <exception
       key="GlobalExceptionHandler.default"
       type="java.lang.Exception"
       path="/ErrorPage.jsp">
       <set-property key="SILENT_IF_COMMITTED" value="true" />
   </exception>
  

To be effective, this value must be defined to the literal String "true". If it is not defined or defined to any other value, the default behavior will be used.

You only need to use this if you do not want error information displayed in the browser when Struts intercepts an exception after the response has been committed.

Since:

Struts 1.3

See Also:

Constant Field Values

Constructor Detail

ExceptionHandler

public ExceptionHandler()

Method Detail

execute

public ActionForward execute(Exception ex,
                             ExceptionConfig ae,
                             ActionMapping mapping,
                             ActionForm formInstance,
                             HttpServletRequest request,
                             HttpServletResponse response)
                      throws ServletException

Handle the Exception. Return the ActionForward instance (if any) returned by the called ExceptionHandler.

Parameters:

ex - The exception to handle

ae - The ExceptionConfig corresponding to the exception

mapping - The ActionMapping we are processing

formInstance - The ActionForm we are processing

request - The servlet request we are processing

response - The servlet response we are creating

Returns:

The ActionForward instance (if any) returned by the called ExceptionHandler.

Throws:

ServletException - if a servlet exception occurs

Since:

Struts 1.1

handleCommittedResponse

protected void handleCommittedResponse(Exception ex,
                                       ExceptionConfig config,
                                       ActionMapping mapping,
                                       ActionForm formInstance,
                                       HttpServletRequest request,
                                       HttpServletResponse response,
                                       ActionForward actionForward)

Attempt to give good information when the response has already been committed when the exception was thrown. This happens often when Tiles is used. Base implementation will see if the INCLUDE_PATH property has been set, or if not, it will attempt to use the same path to which control would have been forwarded.

Parameters:

ex - The exception to handle

config - The ExceptionConfig we are processing

mapping - The ActionMapping we are processing

formInstance - The ActionForm we are processing

request - The servlet request we are processing

response - The servlet response we are creating

actionForward - The ActionForward we are processing

Since:

Struts 1.3

determineIncludePath

protected String determineIncludePath(ExceptionConfig config,
                                      ActionForward actionForward)

Return a path to which an include should be attempted in the case when the response was committed before the ExceptionHandler was invoked.

If the ExceptionConfig has the property INCLUDE_PATH defined, then the value of that property will be returned. Otherwise, the ActionForward path is returned.

Parameters:

config - Configuration element

actionForward - Forward to use on error

Returns:

Path of resource to include

Since:

Struts 1.3

logException

protected void logException(Exception e)

Logs the Exception using commons-logging.

Parameters:

e - The Exception to LOG.

Since:

Struts 1.2

storeException

protected void storeException(HttpServletRequest request,
                              String property,
                              ActionMessage error,
                              ActionForward forward,
                              String scope)

Default implementation for handling an ActionMessage generated from an Exception during Action delegation. The default implementation is to set an attribute of the request or session, as defined by the scope provided (the scope from the exception mapping). An ActionMessages instance is created, the error is added to the collection and the collection is set under the Globals.ERROR_KEY.

Parameters:

request - The request we are handling

property - The property name to use for this error

error - The error generated from the exception mapping

forward - The forward generated from the input path (from the form or exception mapping)

scope - The scope of the exception mapping.

Since:

Struts 1.2