异常的概述：  try+catch处理异常： ~~~ 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("请输入a的值："); a=in.nextInt(); System.out.println("请输入b的值："); b=in.nextInt(); c=a%b; System.out.println("余数为"+c); }catch(Exception e){ System.out.println("输入有误"); } System.out.println("程序顺利进行中"); } } ~~~  用throws处理异常  ~~~ package a1; import java.util.Scanner; class A{ void a(){ int a,b,c; Scanner in =new Scanner(System.in); System.out.println("请输入a的值："); a=in.nextInt(); System.out.println("请输入b的值："); b=in.nextInt(); c=a%b; System.out.println("余数为"+c); } } public class Test1 { public static void main(String[] args) { A aa=new A(); try{ aa.a(); }catch(Exception e){ System.out.println("输入有误"); }finally{ System.out.println("顺利进行中..."); } } } ~~~  finally