How to catch client side errors - html

I have angular2 project, how can I catch errors on client side, error 'Failed to load'. I want to control situation if some of html files doesn't exists my page wouldn't fail, but I'll get exception in console.
Thank you.

As per my understanding, you want to handle exception, so you can done it in typescript using try catch and finally block. typescript allow us to use try catch.
A reference for Try Catch
https://www.c-sharpcorner.com/UploadFile/5089e0/try-catch-statement-in-typescript/
If you need in html, then you need to handle as case in html using some variables

Related

How to manipulate ParseException in Javacc

I have created a lexer and parser in javacc and I am trying to handle errors. I initially tried using try-catch blocks for each symbol that is missing in the parser but I read online something about catching the ParseException only once in the main block with a try-catch and manipulating it to get the last token read and next token and more similar things. I am trying to know more about it but I did not come across anything else as most places use try-catch blocks.
Till now, I know I can do : e.currentToken.image if I catch (ParseException e) and also e.getErrorOffset(), but would like to know if there are other methods that can be used to print a more human-readable and informative error. If anyone has any examples or could direct me to some document.Thanks in advance.
The best way to get better (or different) error messages may be to modify the ParseException class itself.

ejb-3.0 customized exception

My ejb3 application running on JBOSS6 already has a customized Exception handler "Ejbexception.java" which extends Exception class
I want to use the same to trap Exceptions with some number and send back the same to the Client Code for handling gentel message .
ex:
try{
.....
}catch(SQLException ex){
throw new EjbException("1001");
}
Now HOWto get the "1001" on the Client Code ?????
thx in advance
karthik
Did you write this Ejbexception class yourself? If so, that's a poor choice of name, because there's already a javax.ejb.EJBException in the library. However, it will work: when you throw it, the container will transport it to the client, who can then catch it. The string you inserted will be available from the exception's getMessage() method, just like normal.
If you're actually throwing a javax.ejb.EJBException here, then things are slightly different. That exception is aimed at the container, not the client. I actually don't know how it's made visible to the client. My suggestion would be to switch to using a custom exception, which the container will then pass to the client.

kohana how to handle exceptions

I have a question about kohana exceptions.
I have a site that I want to put in production, and I don't want the exceptions to be simply thrown (like they are now), but I want to redirect the user to another page in case of an exception occured.
I use kohana 3, and I wonder: how can I catch an exception and redirect the user to another page if an exception happens:
example of code:
instead of
if ( ! $sale->loaded())
{
throw new Kohana_Request_Exception('Sale not found.');
}
I want: something like: page not found.
thank you!
What you'll need to do is register your own exception handler.
Take a look at the Error Handling documentation for an idea on what to do. Basically, you can capture any type of exception you want and do something specific with it (such as display a 404 page).

How to handle exception in Struts

How can we handle exceptions in Struts? Please share the sample code.
The following URL should help http://www.objectsource.com/j2eechapters/Ch18-Exception_Handling.htm
Use log4j to log the exceptions,
Never use System.out.println in struts application to catch exceptions, as it is expensive ,
Tutorials for log4j> http://logging.apache.org/log4j/1.2/manual.html
to handle the errors:
in struts project to handle the error objet by using ActionError object and to handle the errors by using ActionErrors object.
for suppose
ActionError ae1=new ActionError("err.one");
ActionError ae2=new ActionError("err.two");
Action Errors aes=new ActionErrors();
aes.add(ae1);
aes.add(ae2);
saveErrors(request,aes);//store the errors object in request object
to handle exception:
1)using try and cach blocks
2)using declarative exception handling technique
to handle the exceptions by using global exceptons tag in struts-config.xml
whenever that exception will be came it executes the gen.jsp page.

Windows Service Error Event

In ASP.Net I can use a http handler or module to catch errors.
I need something equivalent for my windows service.
I'm thinking something like Application.OnError += ErrorHandlingMethod;
Any ideas?
The asp.net features this possibility, as it has a complex execution pipeline, where you want to catch a general error.
This is not the case in windows services, as it only provides you the OnStart method, to start your service stuff.
that also means, that you can easily wrap everything in there with a try ... catch block.
so no need for a general error handling method.
if you want it even more general, than go to the Program.cs, and add that catch block there...