Exception Handling in Struts2 with Spring3

Question

I am new to these technologies and I am using the following frameworks to develop an application:

• Struts 2
• Spring 3

I am implementing all business logic in Spring so in case any exception has occurred I will show the custom message to the end user.

Could you please explain me how to develop an exception handling functionality in these technologies?

Answer 1

As per my understanding the best approach is to define some predefined Exceptions for your Business layer and throws these Exception back to your Action classes.

S2 provides a number of way to handle those exception and display them to the user, here are few of them

Global Exception Handling

Using the Struts 2 framework you can specify in the struts.xml how the framework should handle uncaught exceptions. The handling logic can apply to all actions (global exception handling) or to a specific action. Let's first discuss how to enable global exception handling.

 <global-exception-mappings>
    <exception-mapping exception="org.apache.struts.register.exceptions.SecurityBreachException" result="securityerror" />
     <exception-mapping exception="java.lang.Exception" result="error" />
   </global-exception-mappings>

  <global-results>
        <result name="securityerror">/securityerror.jsp</result>
    <result name="error">/error.jsp</result>
   </global-results>

Even if you want a fine level control you are free to configure exception handling at per Action basis

 <action name="actionspecificexception" class="org.apache.struts.register.action.Register" method="throwSecurityException">
     <exception-mapping exception="org.apache.struts.register.exceptions.SecurityBreachException" 
          result="login" />
      <result>/register.jsp</result>
      <result name="login">/login.jsp</result>
   </action>

Its your preference, how you want to configure them.For details refer to the doc

• Exception-Handling

You have even the option to access Exception details from Value-Stack.By default, the ExceptionMappingInterceptor adds the following values to the Value Stack:

• exception The exception object itself
• exceptionStack The value from the stack trace

and here is the way to access those object in JSP

 <s:property value="%{exception.message}"/>
 <s:property value="%{exceptionStack}"/>

For details refer to the details

• Exception-Configuration

Answer 2

You can pick those

Struts 2

Spring 3