java - 错误: cannot find symbol - Java compile error

Question

我已经研究这个问题有一段时间了，我确信修复就在我面前，但我只是对它视而不见。有人愿意指出为什么我的 int i 给我一个错误吗？

CacheDownloader 类:

  public static void main(String[] args) {
    String strFilePath = "./version.txt";
    try
    {
      FileInputStream fin = new FileInputStream(strFilePath);
     DataInputStream din = new DataInputStream(fin);
     int i = din.readInt();
       System.out.println("int : " + i);
       din.close();
    }
    catch(FileNotFoundException fe)
    {
      System.out.println("FileNotFoundException : " + fe);
    }
    catch(IOException ioe)
    {
      System.out.println("IOException : " + ioe);
    }
  }

    private final int VERSION = i; 

错误:

CacheDownloader.java:54: error: cannot find symbol
        private final int VERSION = i;
                                    ^
  symbol:   variable i
  location: class CacheDownloader

Answer 1

您必须在 try-catch block 之前声明 int i。另外，您必须在 main 方法中声明常量:

  public static void main(String[] args) {
    String strFilePath = "./version.txt";
    int i;
    try
    {
      FileInputStream fin = new FileInputStream(strFilePath);
      DataInputStream din = new DataInputStream(fin);
      i = din.readInt();
      System.out.println("int : " + i);
      din.close();
    }
    catch(FileNotFoundException fe)
    {
      System.out.println("FileNotFoundException : " + fe);
    }
    catch(IOException ioe)
    {
      System.out.println("IOException : " + ioe);
    }
    final int VERSION = i; 
  }