Class ExceptionMappingInterceptor
- All Implemented Interfaces:
- Serializable,- ConditionalInterceptor,- Interceptor
 This interceptor forms the core functionality of the exception handling feature. Exception handling allows you to map
 an exception to a result code, just as if the action returned a result code instead of throwing an unexpected
 exception. When an exception is encountered, it is wrapped with an ExceptionHolder and pushed on the stack,
 providing easy access to the exception from within your result.
 
Note: While you can configure exception mapping in your configuration file at any point, the configuration will not have any effect if this interceptor is not in the interceptor stack for your actions. It is recommended that you make this interceptor the first interceptor on the stack, ensuring that it has full access to catch any exception, even those caused by other interceptors.
Interceptor parameters:
- logEnabled (optional) - Should exceptions also be logged? (boolean true|false)
- logLevel (optional) - what log level should we use (trace, debug, info, warn, error, fatal)? - defaut isdebug
- logCategory (optional) - If provided we would use this category (eg. com.mycompany.app). Default is to useExceptionMappingInterceptor.
The parameters above enables us to log all thrown exceptions with stacktace in our own logfile, and present a friendly webpage (with no stacktrace) to the end user.
Extending the interceptor:
 If you want to add custom handling for publishing the Exception, you may override
 publishException(org.apache.struts2.ActionInvocation, ExceptionHolder). The default implementation
 pushes the given ExceptionHolder on value stack. A custom implementation could add additional logging etc.
 
Example code:
 
 <xwork>
     <package name="default" extends="xwork-default">
         <global-results>
             <result name="error" type="freemarker">error.ftl</result>
         </global-results>
         <global-exception-mappings>
             <exception-mapping exception="java.lang.Exception" result="error"/>
         </global-exception-mappings>
         <action name="test">
             <interceptor-ref name="exception"/>
             <interceptor-ref name="basicStack"/>
             <exception-mapping exception="com.acme.CustomException" result="custom_error"/>
             <result name="custom_error">custom_error.ftl</result>
             <result name="success" type="freemarker">test.ftl</result>
         </action>
     </package>
 </xwork>
 
 
 
 This second example will also log the exceptions using our own category
 com.mycompany.app.unhandled at WARN level.
 
 
 <xwork>
   <package name="something" extends="xwork-default">
      <interceptors>
          <interceptor-stack name="exceptionmappingStack">
              <interceptor-ref name="exception">
                  <param name="logEnabled">true</param>
                  <param name="logCategory">com.mycompany.app.unhandled</param>
                  <param name="logLevel">WARN</param>
              </interceptor-ref>
              <interceptor-ref name="i18n"/>
              <interceptor-ref name="staticParams"/>
              <interceptor-ref name="params"/>
              <interceptor-ref name="validation">
                  <param name="excludeMethods">input,back,cancel,browse</param>
              </interceptor-ref>
          </interceptor-stack>
      </interceptors>
      <default-interceptor-ref name="exceptionmappingStack"/>
      <global-results>
           <result name="unhandledException">/unhandled-exception.jsp</result>
      </global-results>
      <global-exception-mappings>
           <exception-mapping exception="java.lang.Exception" result="unhandledException"/>
      </global-exception-mappings>
      <action name="exceptionDemo" class="org.apache.struts2.showcase.exceptionmapping.ExceptionMappingAction">
          <exception-mapping exception="org.apache.struts2.showcase.exceptionmapping.ExceptionMappingException"
                             result="damm"/>
          <result name="input">index.jsp</result>
          <result name="success">success.jsp</result>
          <result name="damm">damm.jsp</result>
      </action>
   </package>
 </xwork>
 
 - Author:
- Matthew E. Porter (matthew dot porter at metissian dot com), Claus Ibsen
- See Also:
- 
Field SummaryFields
- 
Constructor SummaryConstructors
- 
Method SummaryModifier and TypeMethodDescriptionprotected voidPerforms the actual logging.protected ExceptionMappingConfigfindMappingFromExceptions(List<ExceptionMappingConfig> exceptionMappings, Throwable t) Try to find appropriateExceptionMappingConfigbased on provided ThrowableintReturn the depth to the superclass matching.protected voidHandles the logging of the exception.intercept(ActionInvocation invocation) Override to handle interceptionbooleanprotected voidpublishException(ActionInvocation invocation, ExceptionHolder exceptionHolder) Default implementation to handle ExceptionHolder publishing.voidsetLogCategory(String logCatgory) voidsetLogEnabled(boolean logEnabled) voidsetLogLevel(String logLevel) Methods inherited from class org.apache.struts2.interceptor.AbstractInterceptordestroy, init, setDisabled, shouldIntercept
- 
Field Details- 
categoryLoggerprotected org.apache.logging.log4j.Logger categoryLogger
- 
logEnabledprotected boolean logEnabled
- 
logCategory
- 
logLevel
 
- 
- 
Constructor Details- 
ExceptionMappingInterceptorpublic ExceptionMappingInterceptor()
 
- 
- 
Method Details- 
isLogEnabledpublic boolean isLogEnabled()
- 
setLogEnabledpublic void setLogEnabled(boolean logEnabled) 
- 
getLogCategory
- 
setLogCategory
- 
getLogLevel
- 
setLogLevel
- 
interceptDescription copied from class:AbstractInterceptorOverride to handle interception- Specified by:
- interceptin interface- Interceptor
- Specified by:
- interceptin class- AbstractInterceptor
- Parameters:
- invocation- the action invocation
- Returns:
- the return code, either returned from ActionInvocation.invoke(), or from the interceptor itself.
- Throws:
- Exception- any system-level error, as defined in- Action.execute().
 
- 
handleLoggingHandles the logging of the exception.- Parameters:
- e- the exception to log.
 
- 
doLogPerforms the actual logging.- Parameters:
- logger- the provided logger to use.
- e- the exception to log.
 
- 
findMappingFromExceptionsprotected ExceptionMappingConfig findMappingFromExceptions(List<ExceptionMappingConfig> exceptionMappings, Throwable t) Try to find appropriateExceptionMappingConfigbased on provided Throwable- Parameters:
- exceptionMappings- list of defined exception mappings
- t- caught exception
- Returns:
- appropriate mapping or null
 
- 
getDepthReturn the depth to the superclass matching. 0 means ex matches exactly. Returns -1 if there's no match. Otherwise, returns depth. Lowest depth wins.- Parameters:
- exceptionMapping- the mapping classname
- t- the cause
- Returns:
- the depth, if not found -1 is returned.
 
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publishExceptionDefault implementation to handle ExceptionHolder publishing. Pushes given ExceptionHolder on the stack. Subclasses may override this to customize publishing.- Parameters:
- invocation- The invocation to publish Exception for.
- exceptionHolder- The exceptionHolder wrapping the Exception to publish.
 
 
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