Question

我有一个文本文件，其中包含一些帐户持有人和他们借出的书籍数量。我需要阅读文件，添加帐户数量并添加书籍总数。

这些是账户持有人和账簿总数。

  蒂姆·牛顿14

Leon Jones 21
     比尔鲍勃94

莎拉古丁67

{
    private int count;
    private File inFile, outFile;
    private Scanner input;
    private String name;
    private PrintWriter output;
    private int total;

    public test(String name, String id, String inFileName, String outFileName) {
        inFile = new File(inFileName);
        if (!inFile.exists()) {
            throw new IllegalStateException(inFileName + " does not exist");
        }
        outFile = new File(outFileName);

    }

    public void makeLink() throws FileNotFoundException {
        input = new Scanner(inFile);
        output = new PrintWriter(outFile);

    }

    public void processFiles() {
        try {
            while (input.hasNext()) {
                String line = input.nextLine();
                output.println(line);
            }
        } catch (NullPointerException e) {
            System.out.println(" Scanner not assigned");
        }
    }

    public void closeLink() {
        try {
            input.close();
        } catch (NullPointerException e) {
            System.out.println(" Scanner not assigned");
        }
        try {
            output.close();
        } catch (NullPointerException e) {
            System.out.println(" PrintWriter not assigned");
        }

    }
}

以下是已实施扫描仪答案的已编辑代码：

   public void makeLink() throws FileNotFoundException {
     input = new Scanner(inFile);
     output = new PrintWriter(outFile);
     numbers = new Scanner(inFile)

   }


   public void processFiles() {
     try {
       // your current code then
       while (account.hasNextInt()) {
         String line = input.nextLine()
         while (numbers.hasNextInt()) {
           total += numbers.nextInt();
         }
         output.println(line);
       }
     } catch (NullPointerException e) {
       System.out.println(" Scanner not assigned");
     }
   }

enter code here

Answer 1

使用scanner.hasNextInt()和scanner.nextInt()

您可能想要另一台扫描程序在文件中查找数字：

private Scanner account; // initialise this in makeLink

public void processFiles() {
    try {
        // your current code then
        while (account.hasNextInt()) {
            total += account.nextInt();
        }
    } catch (NullPointerException e) {
        System.out.println(" Scanner not assigned");
    }
}

注意：阅读java API是值得的。

从java中的.txt文件中读取数字并添加它们

1 个答案: