Java中运行错误…扫描程序已关闭？

我有这个代码，它应该从一个名为“Numbers.txt”的文件中读取数据。在这个文件中，它仅仅是2003行十进制数。该程序的目标是读取该文件并进行计算。首先我必须得到平均值，我已经设法做到了，但问题是我现在必须回去得到标准偏差。它编译得很好，但我得到一个运行错误，如下所示：

Exception in thread "main" java.lang.IllegalStateException: Scanner closed
    at java.util.Scanner.ensureOpen(Scanner.java:1115)
    at java.util.Scanner.hasNext(Scanner.java:1379)
    at StatsDemo.main(StatsDemo.java:49)

File rf2 = new File("Numbers.txt"); //reconnect to the FileReader object passing it the filename
    Scanner inputFile2 = new Scanner(rf2);//reconnect to the BufferedReader object passing it the FileReader object.
    sum = 0; //reinitialize the sum of the numbers
    count = 0; //reinitialize the number of numbers added
    //priming read to read the first line of the file
    while (inputFile2.hasNext()) //loop that continues until you are at the end of the file
    {
     difference = inputFile2.nextDouble() - mean; //convert the line into a double value and subtract the mean
        sum += Math.pow(difference,2); //add the square of the difference to the sum
        count++; //increment the counter
        if (inputFile2.hasNextDouble())
        inputFile2.nextLine(); //read a new line from the file
    }
  inputFile2.close(); //close the input file
    stdDev = Math.sqrt(sum/count); //store the calculated standard deviation

这是我的代码：

File rf2 = new File("Numbers.txt"); //reconnect to the FileReader object passing it the filename
    Scanner inputFile2 = new Scanner(rf2);//reconnect to the BufferedReader object passing it the FileReader object.
    sum = 0; //reinitialize the sum of the numbers
    count = 0; //reinitialize the number of numbers added
    //priming read to read the first line of the file
    while (inputFile.hasNext()) //loop that continues until you are at the end of the file
    {
     difference = inputFile.nextDouble() - mean; //convert the line into a double value and subtract the mean
        sum += Math.pow(difference,2); //add the square of the difference to the sum
        count++; //increment the counter
        if (inputFile.hasNextDouble())
        inputFile.nextLine(); //read a new line from the file
    }
  inputFile.close(); //close the input file
    stdDev = Math.sqrt(sum/count); //store the calculated standard deviation

我不知道为什么会出现这个错误。我从前面的平均值计算中得到了一个类似的（但不是相同的），但是解决这个问题的方法不适用于这个。有什么想法吗

更改为inputFile2后…

Exception in thread "main" java.lang.IllegalStateException: Scanner closed
at java.util.Scanner.ensureOpen(Scanner.java:1115)
at java.util.Scanner.next(Scanner.java:1510)
at java.util.Scanner.nextDouble(Scanner.java:2456)
at StatsDemo.main(StatsDemo.java:51)

---

您的

扫描仪

称为

inputFile2

而不是

inputFile

将

inputFile

替换为

inputFile2

，因为它是

扫描仪

对象。

将

inputFile

重命名为

inputFile2

，而（inputFile.hasNext（））

您的扫描仪对象带有inputFile2，并且您正在使用inputFile作为扫描仪对象。我很惊讶你的代码是如何在没有编译错误的情况下运行的。如果您有另一个与inputFile Scanner对象关联的文件，而您没有提供上面的代码，只需检查该文件并关闭刷新inputFile对象的引用即可。否则，请按以下方式更正代码：

Exception in thread "main" java.lang.IllegalStateException: Scanner closed
    at java.util.Scanner.ensureOpen(Scanner.java:1115)
    at java.util.Scanner.hasNext(Scanner.java:1379)
    at StatsDemo.main(StatsDemo.java:49)

File rf2 = new File("Numbers.txt"); //reconnect to the FileReader object passing it the filename
    Scanner inputFile2 = new Scanner(rf2);//reconnect to the BufferedReader object passing it the FileReader object.
    sum = 0; //reinitialize the sum of the numbers
    count = 0; //reinitialize the number of numbers added
    //priming read to read the first line of the file
    while (inputFile2.hasNext()) //loop that continues until you are at the end of the file
    {
     difference = inputFile2.nextDouble() - mean; //convert the line into a double value and subtract the mean
        sum += Math.pow(difference,2); //add the square of the difference to the sum
        count++; //increment the counter
        if (inputFile2.hasNextDouble())
        inputFile2.nextLine(); //read a new line from the file
    }
  inputFile2.close(); //close the input file
    stdDev = Math.sqrt(sum/count); //store the calculated standard deviation

---

---别介意我以前的帖子。我是个白痴。断然的。该睡觉了。谢谢大家。没关系，亲爱的。我很乐意帮助你们