Showing Exception Message in client side

[yekkala krishna]

Hi,

Actually in my servlet i am reading devices from a file.
But when FileNotFoundException occurs i need to see that exception in the jsp page.
how can i show the exception message in jsp?
could any body suggest?

	public void doPost(HttpServletRequest req,HttpServletResponse resp)throws Exception{
		String contractName=req.getParameter("contractname");
                                TreeMap  deviceMap=loadDevices(contractName);


                }

private TreeMap<String,String> loadDevices(String contractName){
		System.err.println("DashboardController in loadDevices");
		DataInputStream in=null;
		TreeMap<String,String> deviceMap=new TreeMap<String, String>();
		String filePrefix=dbProps.getFilePrefix();
		TreeMap<String, String> fileMap= currPerspective.getFiles();
		 String filePath=null;
		 if(contractName!=null){
         filePath=fileMap.get(contractName);
         System.out.println("filePath is ::"+filePath);
		}
		try{
			//if(filePath!=null){
			System.out.println("value of filePrefix is :::"+filePrefix);
			//if(filePath!=null){
		//	if(!filePath.equals("")){
			FileInputStream fstream = new FileInputStream(filePrefix+filePath);

		    in = new DataInputStream(fstream);
		        BufferedReader br = new BufferedReader(new InputStreamReader(in));
		    String strLine;
			while ((strLine = br.readLine()) != null)   {
				  int ind1=strLine.indexOf("+");
				  int ind2=strLine.indexOf("#");
				  strLine=strLine.substring(ind1+1, ind2);
				     deviceMap.put(strLine,strLine);
				  System.out.println ("device name is::"+strLine);
				  System.out.println("device Map is ::+"+deviceMap);
				}
			currPerspective.setDevices(deviceMap);
			//}//if
            }
		catch(NullPointerException e){
			deviceMap=null;
			System.err.println("DashboardController.loadDevices: Null Pointer Exception: "+e.getMessage());
			e.printStackTrace();
		}
		catch (FileNotFoundException e){
			deviceMap=null;
			System.err.println("DashboardController.loadDevices: XML file not found: "+e.getMessage());
			e.printStackTrace();
		    }
		 catch (IOException e) {
			 e.printStackTrace();
			 System.err.println("DashboardController.loadDevices: An IO exception has occurred\n"+e.getMessage());
			}
		finally{

		    try {
		    	if(in!=null){
				in.close();
		    	}
			} catch (IOException e) {
				e.printStackTrace();
			}
            }
	return deviceMap;
	}

Regards,
Rama

[Bear Bibeault]

You can map an error handling page in the deployment descriptor.

But be aware that showing exceptions to uses is generally considered a bad practice. Rather, it is more customary to log the exceptions for the developers, and to show the users a more generic "sorry, but something went wrong" message.

[Kumar Raja]

As Bear suggested, you can configure errors and exceptions in web.xml. Please see the link