How to get a list of concrete Exceptions thrown by a method in Eclipse

问题

Is is possible to get a list (and catch) of the concrete exceptions that can be thrown by a method?

I am calling an API that uses a hierarchy of exceptions, but only declares the top level exception to a method. I want to be able to provide specific behaviour based on the exception, but I don't want to have to trace through the code to find the concrete exceptions that can be thrown.

There may be added complications that the API contains a number of layers separated by interfaces.

Simple example:

public interface MyInterface {
  void doShakyStuff() throws Exception;
}

public class MyImpl implements MyInterface {
  public void doShakyStuff() throws Exception{
    double rand = Math.random();
    if( rand > 0.1 ){
      throw new IOException();
    }
    if( rand > 0.5 ){
      throw new IllegalAccessException();
    }
    else{
      throw new InterruptedException();
    }
  }
}

I want to be able to create the following try/catch as completely as possible and then tweak afterwards:

public class MyClass{
  private MyInterface interface;

  public void doStuff(){
    try{
      interface.doShakyStuff();
    }catch(IOException e){
      // ...
    } catch( IllegalAccessException e){
      // ...
    } catch( InterruptedException e){
      // ...
    } catch(Exception e){
      // something else
    }
  }
}

回答1:

The answer is: no.

The method declares what it throws. If it's only declaring a top-level exception (i.e. Exception in your example) ... then that's all your IDE is going to know about / tell you to catch.

To find every subclass it could throw you'd have to look at the javadocs and/or code to find the subclasses or specific subclass being thrown that you're interested in.

Ultimately if you're using an API that's throwing a superclass of an exception, and there's some reason you need to know the concrete subclass ... it's a badly designed API. The point of throwing the superclass when writing an API is that there's only a single line of logic to deal with it regardless of which subclass is really being thrown.

回答2:

You can do this too.

try{
  interface.doShakyStuff();
}catch(Exception e){
     if(e instanceof IOException){
     }
     if( e instanceof IllegalAccessException ){
     }
     if( e instanceof InterruptedException ){
     } 
}

来源：https://stackoverflow.com/questions/21248921/how-to-get-a-list-of-concrete-exceptions-thrown-by-a-method-in-eclipse

标签

java

eclipse

exception-handling