In Java, is there any way to get(catch) all exceptions
instead of catch the exception individually?
This question is related to
java
exception
file
exception-handling
While I agree it's not good style to catch a raw Exception, there are ways of handling exceptions which provide for superior logging, and the ability to handle the unexpected. Since you are in an exceptional state, you are probably more interested in getting good information than in response time, so instanceof performance shouldn't be a big hit.
try{
// IO code
} catch (Exception e){
if(e instanceof IOException){
// handle this exception type
} else if (e instanceof AnotherExceptionType){
//handle this one
} else {
// We didn't expect this one. What could it be? Let's log it, and let it bubble up the hierarchy.
throw e;
}
}
However, this doesn't take into consideration the fact that IO can also throw Errors. Errors are not Exceptions. Errors are a under a different inheritance hierarchy than Exceptions, though both share the base class Throwable. Since IO can throw Errors, you may want to go so far as to catch Throwable
try{
// IO code
} catch (Throwable t){
if(t instanceof Exception){
if(t instanceof IOException){
// handle this exception type
} else if (t instanceof AnotherExceptionType){
//handle this one
} else {
// We didn't expect this Exception. What could it be? Let's log it, and let it bubble up the hierarchy.
}
} else if (t instanceof Error){
if(t instanceof IOError){
// handle this Error
} else if (t instanceof AnotherError){
//handle different Error
} else {
// We didn't expect this Error. What could it be? Let's log it, and let it bubble up the hierarchy.
}
} else {
// This should never be reached, unless you have subclassed Throwable for your own purposes.
throw t;
}
}
Catch the base exception 'Exception'
try {
//some code
} catch (Exception e) {
//catches exception and all subclasses
}
Yes there is.
try
{
//Read/write file
}catch(Exception ex)
{
//catches all exceptions extended from Exception (which is everything)
}
It is bad practice to catch Exception -- it's just too broad, and you may miss something like a NullPointerException in your own code.
For most file operations, IOException is the root exception. Better to catch that, instead.
You may catch multiple exceptions in single catch block.
try{
// somecode throwing multiple exceptions;
} catch (Exception1 | Exception2 | Exception3 exception){
// handle exception.
}
Do you mean catch an Exception
of any type that is thrown, as opposed to just specific Exceptions?
If so:
try {
//...file IO...
} catch(Exception e) {
//...do stuff with e, such as check its type or log it...
}
Source: Stackoverflow.com