运行以下代码“线程“主”java.lang.RuntimeException 中的异常”后出现此错误。我该如何解决？答案

【问题标题】：I am getting this error after I run the following code "Exception in thread "main" java.lang.RuntimeException". How can I fix it?运行以下代码“线程“主”java.lang.RuntimeException 中的异常”后出现此错误。我该如何解决？
【发布时间】：2016-11-09 12:47:54
【问题描述】：

import java.util.concurrent.ExecutionException; 
import java.util.concurrent.ExecutorService; 
import java.util.concurrent.Executors; 
import java.util.concurrent.Future; 

public class Fibonacci { 


    private static long[] value; 
    public static void main(String args[]) throws InterruptedException { 
        int n;
        try { 
            n = Integer.parseInt(args[0]); 
        } catch (Exception e) { 
            throw new RuntimeException(" number n"); 
        }

        value = new long[n + 1]; 
        long start = System.nanoTime(); 
        System.out.print("Dynamic Programming = " + fibon(n)); 
        long end = System.nanoTime(); 

        System.out.println("\t time = " + (end - start) + "ns"); 
        start = System.nanoTime(); 

        System.out.print("Sequence = " + Sequence(n));
        end = System.nanoTime(); 

        System.out.println("\t time = " + (end - start) + "ns"); 
        start = System.nanoTime(); 

        //int nThreads = Runtime.getRuntime().availableProcessors(); 
        int nThreads = 30; 
         ExecutorService executorService = Executors 
                .newFixedThreadPool(nThreads); 
        int result; 
        try { 
            result = fibonacciSum(n, executorService); }
        catch (ExecutionException e) { 
            throw new RuntimeException("Thread Interuppted "); } 

        System.out.print(" MultiThreading = " + result); 
        end = System.nanoTime(); 
        System.out.println("\t time = " + (end - start) + "ns"); 
    } 

    public static long fibon(int n) { 
        value[0] = 1; 
        value[1] = 1; 
            if (n <= 2) 
            return 1;

          else if (value[n - 1] != 0) 
          return value[n]; 

        for (int j = 2; j <= n; j++) { 
           value[j] = fibon(j - 2) + fibon(j - 1); } 
            return value[n]; 
    } 

    public static long Sequence(int n) { 
        if (n <= 2) 
            return 1; 
        else 
            return (Sequence(n - 1) + Sequence(n - 2)); 
    } 

    private static class FibonacciThread implements Runnable { 
        int index; 
        int result; 
        ExecutorService executorService; 
        public FibonacciThread(int index) { 
            this.index = index; 
        } 
         public void run() { 

            try { 
                this.result = fibonacciSum(index, executorService); 
            } catch (Exception e) { 
                throw new RuntimeException("Thread interupted"); 
            } 
        } 
    } 

    private static int fibonacciSum(int index, ExecutorService executorService) 
      throws InterruptedException, ExecutionException { 
        if (index == 1 || index == 2) { 
            return 1; 
        } else {   

            FibonacciThread fibonacciThread1 = new FibonacciThread(index - 2); 
            fibonacciThread1.executorService=executorService; 
            Future future = executorService.submit(fibonacciThread1); 
            Object object = future.get(); 
            int resultPart2 = fibonacciSum(index - 1, executorService); 
            int result = fibonacciThread1.result + resultPart2; 
           //executorService.shutdown(); 
           return result; 
        } 
    } 
}

运行上述代码后出现此错误。

线程“main”中的异常 java.lang.RuntimeException: Number n at Fibonacci.main(Fibonacci.java:16)

请告诉我如何解决这个问题。该程序假定工作如下：在命令行中，用户将输入程序要生成的斐波那契数。然后程序将创建一个单独的线程来生成斐波那契数，将序列放入线程可以共享的数据中（数组可能是最方便的数据结构）。

【问题讨论】：

确保你用java Fibonacci <value-of-n>启动你的程序，否则你会得到这个异常，因为你的程序除了一个参数
你如何运行你的程序？顺便说一句，你觉得throw new RuntimeException(" number n"); 做什么？
请将您的示例代码缩减为minimal reproducible example。最少的代码通常不应该包含计时例程，除非问题是专门针对那个方面的。

标签： java multithreading fibonacci

【解决方案1】：

当您运行程序时，您应该在命令中提供参数。使用以下命令，其中“n”应该是程序要生成的斐波那契数的整数

java 斐波那契数

【讨论】：

【解决方案2】：

要从标准输入流中读取，请从 System.in 流中读取。传递给 main 方法的字符串数组是命令行参数，而不是用户输入数据。

【讨论】：