In J2EE / servlet web application, you can map error page to specify exception like this :

web.xml

      	
       
        404
       	
       
        /WEB-INF/pages/404.jsp
         
         
      	
       
        com.mkyong.web.exception.CustomException
       	
       
        /WEB-INF/pages/error/custom_error.jsp
         
         
      	
       
        java.lang.Exception
       	
       
        /WEB-INF/pages/generic_error.jsp
         
      

The above code should be self-exploratory. If the exception handling function exists in the servlet container, why we still need to use the Spring to handle the exception?

Generally, there are two reasons :

1. Customize Error Page – The servlet container will render the error page directly; While the Spring allows you to populate model or data to the error page, so that you can customize a more user friendly error page.
2. Business logic – Spring allow you to apply extra business logic before rendering the error page, like logging, auditing and etc.

In this tutorial, we will show you two examples to handle the exception in Spring.

1. For Spring 2.x, we use SimpleMappingExceptionResolver in the XML file.
2. For Spring 3.x, we can simplify the XML configuration via @ExceptionHandler annotation.

1. SimpleMappingExceptionResolver Example

Review the directory structure.

A custom exception.

CustomGenericException.java

package com.mkyong.web.exception; public class CustomGenericException extends RuntimeException {
      	private static final long serialVersionUID = 1L; 	private String errCode;	private String errMsg; 	//getter and setter methods 	public CustomGenericException(String errCode, String errMsg) {
     		this.errCode = errCode;		this.errMsg = errMsg;	} }

This controller class, just throw a CustomGenericException with custom error code and error description.

CustomerController.java

package com.mkyong.web.controller; import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.mvc.AbstractController;import com.mkyong.web.exception.CustomGenericException; public class CustomerController extends AbstractController {
        @Override  protected ModelAndView handleRequestInternal(HttpServletRequest request,	HttpServletResponse response) throws Exception {
      	throw new CustomGenericException("E888", "This is custom message - ABC");   } }

Review the SimpleMappingExceptionResolver below :

mvc-dispatcher-servlet.xml

      
        	
        	
        	
       	
        	
       	  
        		
         			
          
           				error/generic_error			
          			
          
           error/exception_error
          		
         	  
        	
        	
       		
        			
         
          /WEB-INF/pages/
         		
        		
        			
         
          .jsp
         		
        	
        	
        
      

In above, when

1. CustomGenericException is thrown, it will map to the view name “error/generic_error”.
2. Any other Exceptions is thrown, it will map to the view name “error/exception_error”.

In the JSP page, you can access the exception instance via ${exception}.

pages/error/generic_error.jsp.jsp

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> 	
      		
       
${exception.errCode} : System Errors
	
       	
      		
       
System Errors
	
       	
      		
       
${exception.errMsg}
	
       

Demo – http://localhost:8080/SpringMvcExample/customer

Download it –   (13KB)

 

2. @ExceptionHandler Example

Since Spring 3.0, there is a new annotation @ExceptionHandler to simplify the XML configuration. Below is the equivalent version using @ExceptionHandler.

CustomerController.java

package com.mkyong.web.controller; import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.servlet.ModelAndView;import com.mkyong.web.exception.CustomGenericException; @Controllerpublic class CustomerController {
      	@RequestMapping(value = "/customer", method = RequestMethod.GET)	public ModelAndView getPages() throws Exception {
      		throw new CustomGenericException("E888", "This is custom message X"); 	} 	@ExceptionHandler(CustomGenericException.class)	public ModelAndView handleCustomException(CustomGenericException ex) {
      		ModelAndView model = new ModelAndView("error/generic_error");		model.addObject("exception", ex);		return model; 	} 	@ExceptionHandler(Exception.class)	public ModelAndView handleAllException(Exception ex) {
      		ModelAndView model = new ModelAndView("error/exception_error");		return model; 	} }

Nothing to declare in Spring XML file.

mvc-dispatcher-servlet.xml

      
        	
        	
       		
        			
         
          /WEB-INF/pages/
         		
        		
        			
         
          .jsp
         		
        	
        	
        
      

Download it –   (15KB)

Note

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