Java programming Step four: Throwing exceptions

First, exception declaration

Second, code example

1. Example One

Class Openexception extends Throwable {}public class readfile{public static int open () {return-1;} public static void  ReadFile () throws Openexception {if (open () = =-1) {throw new Openexception ();}} public static void Main (string[] args) {try {readFile ();} catch (Openexception e)  {}}}

The declared exception must inherit from Throwable, and the exception thrown is not processed, just returned to the caller.

2. Example Two

Class Openexception extends Throwable {}class closeexception extends Throwable {}public class readfile{public static int o Pen () {return-1;} public static void  ReadFile () throws Openexception,closeexception {if (open () = =-1) {throw new Openexception ();}} public static void Main (string[] args) {try {readFile ()} catch (Openexception e) {} catch (Closeexception e) {}}}

After the exception declaration, the exceptions that can be thrown are not limited and can throw multiple types of exceptions.

Iii. Summary of today

Java programming Step four: Throwing exceptions