Java Java.io.FileInputStream.getChannel() 方法

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  描述

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

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

   public FileChannel getChannel()

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  参数

  不适用
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  返回值

  该方法返回与此文件输入流关联的通道。
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  异常

  不适用
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  例子

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

   
  package com.jc2182; 
  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。该文件将用作示例程序的输入-

   ABCDEF

  让我们编译并运行以上程序，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