Java Java.io.FileInputStream.getChannel()用法及代码示例

描述

这个java.io.FileInputStream.getChannel()返回与此文件输入流关联的唯一 FileChannel 对象。返回通道的位置到目前为止从文件中读取的字节数。

声明

以下是声明java.io.FileInputStream.getChannel()方法 -

public FileChannel getChannel()

参数

NA

返回值

这些方法返回与此文件输入流相关联的通道。

异常

NA

示例

下面的例子展示了 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，其内容如下。该文件将用作我们示例程序的输入 -

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