1 import javax.swing.*; 2 3 class AboutException { 4 public static void main(String[] a) 5 { 6 int i=1, j=0, k; 7 k=i/j; 8 9 10 try 11 { 12 13 k = i/j; // Causes division-by-zero exception 14 //throw new Exception("Hello.Exception!"); 15 } 16 17 catch ( ArithmeticException e) 18 { 19 System.out.println("被0除. "+ e.getMessage()); 20 } 21 22 catch (Exception e) 23 { 24 if (e instanceof ArithmeticException) 25 System.out.println("被0除"); 26 else 27 { 28 System.out.println(e.getMessage()); 29 30 } 31 } 32 33 34 finally 35 { 36 JOptionPane.showConfirmDialog(null,"OK"); 37 } 38 39 } 40 }
运行结果:
Exception in thread "main" java.lang.ArithmeticException: / by zero
at lianxi/JavaApp1.AboutException.main(AboutException.java:9)
package JavaApp1; import javax.swing.*; public class CatchWho { public static void main(String[] args) { try { try { throw new ArrayIndexOutOfBoundsException(); } catch(ArrayIndexOutOfBoundsException e) { System.out.println( "ArrayIndexOutOfBoundsException" + "/内层try-catch"); } throw new ArithmeticException(); } catch(ArithmeticException e) { System.out.println("发生ArithmeticException"); } catch(ArrayIndexOutOfBoundsException e) { System.out.println( "ArrayIndexOutOfBoundsException" + "/外层try-catch"); } } }
运行结果:
ArrayIndexOutOfBoundsException/内层try-catch
发生ArithmeticException
最后一个没有抛出异常,所以没有输出。
package JavaApp; public class CatchWho2 { public static void main(String[] args) { try { try { throw new ArrayIndexOutOfBoundsException(); } catch(ArithmeticException e) { System.out.println( "ArrayIndexOutOfBoundsException" + "/内层try-catch"); } throw new ArithmeticException(); } catch(ArithmeticException e) { System.out.println("发生ArithmeticException"); } catch(ArrayIndexOutOfBoundsException e) { System.out.println( "ArrayIndexOutOfBoundsException" + "/外层try-catch"); } } }
package JavaApp; public class EmbededFinally { public static void main(String args[]) { int result; try { System.out.println("in Level 1"); try { System.out.println("in Level 2"); // result=100/0; //Level 2 try { System.out.println("in Level 3"); result=100/0; //Level 3 } catch (Exception e) { System.out.println("Level 3:" + e.getClass().toString()); } finally { System.out.println("In Level 3 finally"); } // result=100/0; //Level 2 } catch (Exception e) { System.out.println("Level 2:" + e.getClass().toString()); } finally { System.out.println("In Level 2 finally"); } // result = 100 / 0; //level 1 } catch (Exception e) { System.out.println("Level 1:" + e.getClass().toString()); } finally { System.out.println("In Level 1 finally"); } } }
运行结果:
in Level 1
in Level 2
in Level 3
Level 3:class java.lang.ArithmeticException
In Level 3 finally
In Level 2 finally
In Level 1 finally
try嵌套依次执行,由于只有第三个中存在异常,所以捕获到了异常,finlly语句全部依次输出。
package JavaApp; public class SystemExitAndFinally { public static void main(String[] args) { try{ System.out.println("in main"); throw new Exception("Exception is thrown in main"); //System.exit(0); } catch(Exception e) { System.out.println(e.getMessage()); System.exit(0); } finally { System.out.println("in finally"); } } }
运行结果:
in main
Exception is thrown in main
可知finally语句不一定会执行。