Java Java.io.FileInputStream.getChannel() 方法

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）。

声明

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

 public FileChannel getChannel()

参数

不适用

返回值

该方法返回与此文件输入流关联的通道。

异常

不适用

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