java - 将文件加载到二维数组时出现 CSV 错误

Question

我有一个 CSV 文件，我的任务包括获取该文件并将其加载到二维数组中。我已经计算了有多少行以及有多少列，但是当我将其加载到数组中时，我收到错误

"non-static variable filetable cannot be referenced from a static context"

但是如果我这样做public static String[][] filetable = new String[rows][cols];

我收到错误

Illegal reference forward Usage of static non-final variable during intialization

代码:

public String[][] filetable = new String[rows][cols];//The second error doesn't show up here since I haven't put 'static' after public.
public static int rows = 0;
public static int cols = 0;

 public static void to_Array(File example)
{        


 try 
    {
         FileReader file = new FileReader(example);
         Scanner sc = new Scanner(file);  

         if(sc.hasNextLine())
         { 
             String[] tokens = sc.nextLine().split(",");
             cols = tokens.length;
             rows++;
         }

         while(sc.hasNextLine())
         {
             rows++;
             sc.nextLine();                 
         }

         //Probably not the right way to load the file into the array, but will fix it later
         for(int r = 0; r < rows; r++)
         {
             for(int c = 0; c < cols; c++)
             {
                 filetable[r][c] = sc.next();// This where the first error shows up
             }
         }


    } 
    catch (FileNotFoundException e) 
    {
        System.out.println(e);
    }

Answer 1

public static void  method 

如果方法是静态的，则仅当局部变量也是静态的时才可以引用它们

public SomeClass {
  private static String var1;
  private String var2;

  public void someMethod(){
     this.var2 // is allowed 
     this.var1 // is allowed
   }

   public static void someMethod(){
     this.var2 // is allowed 
     this.var1 // is not allowed
   }



}

我建议您在类中创建一个方法，而不是在 main() 方法中创建该类的新实例，然后调用该方法

 SomeClass test = new SomeClass():
  test.someMethod()// copy the code of the main to this method