FileChannel getChannel

描述

所述java.io.FileInputStream.getChannel（）返回与此文件输入流有关的唯一FileChannel对象。返回通道的位置到目前为止从文件读取的字节数。

声明

以下是java.io.FileInputStream.getChannel（）方法的声明

public FileChannel getChannel()

参数

NA

返回值

这些方法返回与此文件输入流相关的通道。

异常

NA

实例

以下示例显示了java.io.FileInputStream.getChannel（）方法的用法。

package com.tutorialspoint;

import java.io.IOException;
import java.io.FileInputStream;
import java.nio.channels.FileChannel;

public class FileInputStreamDemo {
   public static void main(String[] args) throws IOException {
      FileChannel fc = null;
      FileInputStream fis = null;
      int i = 0;
      long pos;
      char c;

      try {
         // create new file input stream
         fis = new FileInputStream("C://test.txt");

         // read till the end of the file
         while((i = fis.read())!=-1) {

            // get file channel
            fc = fis.getChannel();

            // get channel position
            pos = fc.position();

            // integer to character
            c = (char)i;

            // prints
            System.out.print("No of bytes read: "+pos);
            System.out.println("; Char read: "+c);
         }

      } catch(Exception ex) {
         // if an I/O error occurs
         System.out.println("IOException: close called before read()");
      } finally {
         // releases all system resources from the streams
         if(fis!=null)
            fis.close();
         if(fc!=null)
            fc.close();
      }
   }
}

假设我们有一个文本文件c：/test.txt，它具有以下内容。此文件将用作示例程序的输入 -

ABCDEF

让我们编译并运行上面的程序，这将产生以下结果

No of bytes read: 1; Char read: A
No of bytes read: 2; Char read: B
No of bytes read: 3; Char read: C
No of bytes read: 4; Char read: D
No of bytes read: 5; Char read: E
No of bytes read: 6; Char read: F