java - 使用java读取/提取数据并放入var中

Question

嘿嘿，我有一个问题。我正在尝试编写程序的一部分。我需要做的是读取一个名为marks.txt的文档，然后提取文档中的数据并将其放入变量中，以便我可以计算总数。

文档的布局很简单

Assessment1 41
Assessment2 41
Assessment3 41

当代码运行时，已声明的变量保持为 NULL

这是该部分程序的代码

public void readMarks() 
{
    try {
        doc = new File ("marks.txt");

        if(!doc.exists())
        {
            System.out.println ("Marks.txt Does Not Exist");
        }

        Scanner input = new Scanner(doc);

        while (input.hasNext()) {
            String Assessment1 = input.next();
            int mark1 = input.nextInt();
            String Assessment2 = input.next();
            int mark2 = input.nextInt();
            String Assessment3 = input.next();
            int mark3 = input.nextInt();
        }  

        input.close();
    }
    catch (FileNotFoundException ex) {
        System.err.println("File has not been found");
    } 

}

Answer 1

在循环内声明变量从来都不是一个好主意。我已经尝试过这个解决方案，它工作完美，如果您有任何问题，可能与marks.txt位于不正确的位置有关

public static void readMarks() 
  {
      String Assessment1 = null, Assessment2 = null, Assessment3 = null;
      int mark1 = 0,mark2 = 0,mark3 = 0;
       try {
       File doc = new File ("marks.txt");
       if(!doc.exists())
       {
        System.out.println ("Marks.txt Does Not Exist");
       }
       Scanner input = new Scanner(doc);
         while (input.hasNext()){
          Assessment1 = input.next();
          mark1 = input.nextInt();
          Assessment2 = input.next();
          mark2 = input.nextInt();
          Assessment3 = input.next();
          mark3 = input.nextInt();

        }  
      input.close();
      System.out.println(Assessment1 + " "+mark1 + Assessment2 +mark2+ " " + Assessment3 +mark3+ " ");
    }
    catch (FileNotFoundException ex) {
      System.err.println("File has not been found");
    } 

     }

如果您有任何疑问，请随时询问