Java RandomAccessFile getFilePointer()用法及代碼示例

RandomAccessFile類getFilePointer()方法

• getFilePointer() 方法可在java.io包。
• getFilePointer() 方法用於獲取 RandomAccessFile 流中的當前指針。
• getFilePointer() 方法是一個非靜態方法，它隻能通過類對象訪問，如果我們嘗試使用類名訪問方法，那麽我們將得到一個錯誤。
• getFilePointer() 方法在返回文件指針時不拋出異常。

用法:

    public long getFilePointer();

參數：

• 它不接受任何參數。

返回值：

這個方法的返回類型是long，它返回下一次讀取或寫入發生的文件開頭的指針。

例：

// Java program to demonstrate the example 
// of long getFilePointer() method of
// RandomAccessFile

import java.io.*;

class RAFGetFilePointer {
 public static void main(String[] args) throws Exception {
  // Instantiate a random access file
  // object with file name and permissions
  RandomAccessFile ra_f = new RandomAccessFile("e:/includehelp.txt", "rw");

  // By using writeUTF() method is to 
  // write data in the file
  ra_f.writeUTF("Welcome, in Java World!!!");

  // Initially set the file pointer
  // is at 0 for reading the file
  ra_f.seek(0);

  // To read file content by using
  // readUTF()
  System.out.println("ra_f .readUTF():" + ra_f.readUTF());

  // By using getFilePointer() method is to
  // return the file pointer in bytes at which
  // the next read/write occurs
  System.out.println("ra_f.getFilePointer():" + ra_f.getFilePointer());

  // By using close() method isto
  // close this stream ran_f
  ra_f.close();
 }
}

輸出

ra_f .readUTF():Welcome, in Java World!!!
ra_f.getFilePointer():27