1.异常处理：

使用try_throw_catch块模块

优点：将检测错误（由被调用的方法完成）从处理错误（由调用方法完成）中分离出来。

例子：

1 package test; 2 import java.util.Scanner; 3 public class Demo { 4  5     public static void main(String[] args) { 6          7     Scanner input = new Scanner(System.in); 8     System.out.print("Enter two integers: "); 9     int number1 = input.nextInt();10     int number2 = input.nextInt();11     12     try {  //try块包含正常情况下执行的代码13     int result = quotient(number1,number2);14     System.out.println(number1 + " / "+ number2 + " is "+result);15     }16     catch(ArithmeticException ex)   //异常被catch所捕获17     {18         System.out.println("Exception: an integer " + " Cannot be divided by zero ");19     }20     System.out.println("Execution continues...");21     }22     23     public static int quotient(int number1,int number2)24     {25         if(number2==0)26         {27             throw new ArithmeticException("Divisor cannot be zero");28             //System.exit(1);//表示非正常退出程序29         }30         return number1/number2;31     }32 }

例子二：输入类型有错误，抛出异常

1 package test; 2 import java.util.*;//代表你导入了java.util包中的所有类,, 3 public class Demo { 4  5     public static void main(String[] args) { 6          7     Scanner input = new Scanner(System.in); 8     boolean continueInput = true; 9     10     do {11         try {12             System.out.print("Enter an integers: ");13             int number = input.nextInt();14             15             System.out.println("The number entered is "+ number);16             continueInput = false;17         }18         catch(InputMismatchException ex)19         {20             System.out.println("try again.(" + "Incorrect input: an integer id=s required)");21             input.nextLine();//接受输入的一行数据 以/r为结束22         }23     }while(continueInput);24     }25 }