09. Spring - Exception handling globally.

 

Exception handling globally.

////////////////////////////////// ---------  Extra code for custom exception.----------- //////////////////////////////////

 

Understand bellow code to get understand about how java custom exceptions can be handled.

public class Test {

public static void main(String[] args) throws Exception {

try{

myMethod();

}catch(Exception e){

System.out.println(e);

}

}

static void myMethod() throws MyException {

throw new MyException("Custom occured");

}

}

class MyException extends Exception {

MyException(String s) { super(s);}

}

///////////////////////////////// ----------------------------------------------------------------- //////////////////////////////////

@ControllerAdvice – Every controller get advice from this class.

Create a custom exception handle class and global exception handler class and jsp page for show exception.

@Controller

publicclassPageController {

@RequestMapping(value = "/show/{id}/product")

Public ModelAndView showSingleProduct(@PathVariableint id) throws ProductNotFoundException {

return mv;

}

}

import java.io.PrintWriter;

import java.io.StringWriter;

import org.springframework.web.bind.annotation.ControllerAdvice;

import org.springframework.web.bind.annotation.ExceptionHandler;

import org.springframework.web.servlet.ModelAndView;

import org.springframework.web.servlet.NoHandlerFoundException;

@ControllerAdvice

public class GlobalDefaultExceptionHandler {

@ExceptionHandler(NoHandlerFoundException.class)

public ModelAndView handlerNoHandlerFoundException() {

ModelAndView mv = new ModelAndView("error");

mv.addObject("errorTitle", "The page is not constructed!");

mv.addObject("errorDescription", "The page you are looking for is not available now!");

mv.addObject("title", "404 Error Page");

return mv;

}

@ExceptionHandler(ProductNotFoundException.class)

public ModelAndView handlerProductNotFoundException() {

ModelAndView mv = new ModelAndView("error");

mv.addObject("errorTitle", "Product not available!");

mv.addObject("errorDescription", "The product you are looking for is not available right now!");

mv.addObject("title", "Product Unavailable");

return mv;

}

@ExceptionHandler(Exception.class)

public ModelAndView handlerException(Exceptionex) {

ModelAndView mv = new ModelAndView("error");

mv.addObject("errorTitle", "Contact Your Administrator!!");

/* only for debugging your application*/

StringWriter sw = new StringWriter();

PrintWriter pw = new PrintWriter(sw);

ex.printStackTrace(pw);

mv.addObject("errorDescription", sw.toString());

mv.addObject("title", "Error");

return mv;

}

}

import java.io.Serializable;

public class ProductNotFoundException extends Exception implements Serializable {

private static final long serialVersionUID = 1L;

private String message;

public ProductNotFoundException() {

this("Product is not available!");

}

Public ProductNotFoundException(String message) {

this.message = System.currentTimeMillis() + ": " + message;

}

Public String getMessage() {

return message;

}

}

Do modification in web.xml like bellow.

<servlet>

<servlet-name>dispatcher</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<!-- FOr throwing exception -->

<init-param>

<param-name>throwExceptionIfNoHandlerFound</param-name>

<param-value>true</param-value>

</init-param>

</servlet>