異常的概述：  try+catch處理異常： ~~~ package a1; import java.util.Scanner; public class Test { public static void main(String[] args) { Scanner in =new Scanner(System.in); int a; int b; int c; try{ System.out.println("請輸入a的值："); a=in.nextInt(); System.out.println("請輸入b的值："); b=in.nextInt(); c=a%b; System.out.println("余數為"+c); }catch(Exception e){ System.out.println("輸入有誤"); } System.out.println("程序順利進行中"); } } ~~~  用throws處理異常  ~~~ package a1; import java.util.Scanner; class A{ void a(){ int a,b,c; Scanner in =new Scanner(System.in); System.out.println("請輸入a的值："); a=in.nextInt(); System.out.println("請輸入b的值："); b=in.nextInt(); c=a%b; System.out.println("余數為"+c); } } public class Test1 { public static void main(String[] args) { A aa=new A(); try{ aa.a(); }catch(Exception e){ System.out.println("輸入有誤"); }finally{ System.out.println("順利進行中..."); } } } ~~~  finally