我可以执行与一个try块对应的多个catch块吗？

Question

Consider I have a try block that contains 3 statements, and all of them cause Exceptions. I want all the 3 exceptions to be handled by their relevant catch blocks.. is it possible ?

something like this-->

class multicatch
{
    public static void main(String[] args)
    {
        int[] c={1};
        String s="this is a false integer";
        try
        {
            int x=5/args.length;
            c[10]=12;
            int y=Integer.parseInt(s);
        }
        catch(ArithmeticException ae)
        {
            System.out.println("Cannot divide a number by zero.");
        }
        catch(ArrayIndexOutOfBoundsException abe)
        {
            System.out.println("This array index is not accessible.");
        }
        catch(NumberFormatException nfe)
        {
            System.out.println("Cannot parse a non-integer string.");
        }
    }
}

Is it possible to obtain the following output? -->>

Cannot divide a number by zero.
This array index is not accessible.
Cannot parse a non-integer string.

Answer 1

Is it possible to obtain the following output?

No, because only one of the exceptions will be thrown. Execution leaves the try block as soon as the exception is thrown, and assuming there's a matching catch block, it continues there. It doesn't go back into the try block, so you can't end up with a second exception.

See the Java tutorial for a general lesson in exception handling, and section 11.3 of the JLS for more details.

Answer 2

If you want to catch multiple exceptions, you have to split your code across multiple try/catch blocks.

A better approach is to validate your data and log errors without triggering Exceptions to do this.

Answer 3

To add to Jon's answer, while you won't catch multiple exceptions from a single try block, you can have multiple handlers handle a single exception.

try
{
    try
    {
        throw new Exception("This is an exception.");
    }
    catch(Exception foo)
    {
        System.Console.WriteLine(foo.Message);
        throw; // rethrows foo for the next handler.
    }
}
catch(Exception bar)
{
    System.Console.WriteLine("And again: " + bar.Message);
}

This produces the output:

This is an exception.
And again: This is an exception.

Answer 4

this is a REALY BAD PRACTICE, but you can do next (solve your problem using finally block):

private static void Main()
        {
            int[] c={1};
            String s="this is a false integer";
            try
            {
                int z = 0;
                int x = 5/z;
            }
            catch (ArithmeticException exception)
            {
                Console.WriteLine(exception.GetType().ToString());
            }
            finally
            {
                try
                {
                    c[10] = 12;
                }
                catch(IndexOutOfRangeException exception)
                {
                    Console.WriteLine(exception.GetType().ToString());
                }
                finally
                {
                    try
                    {
                        int y = int.Parse(s);
                    }
                    catch (FormatException exception)
                    {
                        Console.WriteLine(exception.GetType().ToString());
                    }
                }

                Console.ReadKey();
            }
        } 

Answer 5

Showing all of the exceptions handling at once is impossible. The goal of each exception catch is to have a different handling for each Exception type and otherwise it's pointless to print them all together.

Answer 6

No ,

It will not execute all three catch statements. The TRY block checks for error and then the execution comes out of the TRY block. Then Suitable catch will be executed. In your case, The ArithmeticException is in the Top of the Exception Hierarchy. So it will Execute and then the program terminates.

If you give, Catch(Exception e) before ArithmeticException then Exception catch will be executed... Better read about the SystemException Hierarchies at MSDN