onoffswitch.java

java的异常部分ppt

//: c10:OnOffSwitch.java 
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// Why use finally?

class Switch {
  boolean state = false;
  boolean read() { return state; }
  void on() { state = true; }
  void off() { state = false; }
} 
class OnOffException1 extends Exception {}
class OnOffException2 extends Exception {}

public class OnOffSwitch {
  static Switch sw = new Switch();
  static void f() throws 
    OnOffException1, OnOffException2 {}
  public static void main(String[] args) {
    try {
      sw.on();
      // Code that can throw exceptions...
      f();
      sw.off();
    } catch(OnOffException1 e) {
      System.err.println("OnOffException1");
      sw.off();
    } catch(OnOffException2 e) {
      System.err.println("OnOffException2");
      sw.off();
    }
  }
} ///:~