Question

import java.util.Scanner;

public class test{
   public static void main(String[]args){
       Scanner gogosi = new Scanner(System.in);
        if(gogosi.nextInt()<=0) {

    System.out.print("Error");

        }else if(gogosi.nextInt()<=51){

    System.out.print("Please go take your order");

        }else if(gogosi.nextInt()>=51){

    System.out.print("Your gonna get fat");

        }else{
            System.out.print("Error");
        }
   }
}




Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at test.main(test.java:10)

所以..我不t see what is wrong, i tried, but didnt find any solutuions, please help? I scanned the code but it still doesn不工作。 dsfsfsdfsdfsdfsdfsd 标清 F 自卫队自卫队 sdfsdfsdfsdfsdf 自卫队 sdfsdsaddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd

Answer 1

这在JavaDocs中有很好的文档说明，您在调用nextInt（）时没有检查是否还有要读取的内容，如果没有要读取的内容，则将引发NoSuchElementException。确保使用hasNextInt（）读取整数：

    Scanner gogosi = new Scanner(System.in);

    if (gogosi.hasNextInt()) {
        int i = gogosi.nextInt();
        if (i <= 0) {
            System.out.print("Error");
        } else if (i <= 51) {
            System.out.print("Please go take your order");
        } else if (i >= 51) {
            System.out.print("Your gonna get fat");
        } else {
            System.out.print("Error");
        }
    }

    gogosi.close();

另外，您可能（取决于您要执行的操作）希望在第一个输入失败后才能输入另一个输入。为此，您可以在前面的代码周围包裹一个while循环，例如：

    Scanner gogosi = new Scanner(System.in);

    // possibility to exit the loop when you enter 0
    boolean exit = false;
    while (gogosi.hasNextInt() && !exit) {
        int i = gogosi.nextInt();
        if (i == 0) {
            System.out.print("Exit");
            exit = true;
        } else if (i < 0) {
            System.out.print("Error");
        } else if (i <= 51) {
            System.out.print("Please go take your order");
        } else if (i >= 51) {
            System.out.print("Your gonna get fat");
        }
        // note: else removed because it will never be reached anyway
    }

    gogosi.close();

Answer 2

命令行参数存储在args参数中。
参见：Command-Line Arguments。

启动应用程序时，运行时系统将传递通过数组对应用程序的main方法的命令行参数的Strings。

如果您仅传递一个数字，那么它将在args[0]中。
然后，您只需要获取它，将其存储在变量中，然后进行比较即可。

  public static void main(String[] args)
  {   
     //Scanner gogosi = new Scanner(System.in);
     //int x = gogosi.nextInt();

     int x = Integer.parseInt(args[0]);

     if (x<=0) {
        System.out.print("Error");
     } else if(x<=51) {
        System.out.print("Please go take your order");
     } else if(x>=51) {
        System.out.print("Your gonna get fat");
     } else {
        System.out.print("Error");
     }
  }

不需要Scanner。

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2 个答案: