java.io.BufferedInputStream.available() 方法返回从输入流中读取不受阻塞，输入流方法的下一次调用的剩余字节数。

声明

以下是java.io.BufferedInputStream.available()方法的声明

public int available()

返回值

此方法返回的字节数保持从此输入流中读取而不阻塞。

异常

• IOException -- -- 如果发生I/O错误.

例子

下面的示例演示java.io.BufferedInputStream.available()方法的用法。

package com.yiibai;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class BufferedInputStreamDemo {
   public static void main(String[] args) throws Exception {

      InputStream inStream = null;
      BufferedInputStream bis = null;

      try{
         // open input stream test.txt for reading purpose.
         inStream = new FileInputStream("c:/test.txt");

         // input stream is converted to buffered input stream
         bis = new BufferedInputStream(inStream);      

         // read until a single byte is available
         while( bis.available() > 0 )
         {
            // get the number of bytes available
            Integer nBytes = bis.available();
            System.out.println("Available bytes = " + nBytes );

            // read next available character
            char ch =  (char)bis.read();

            // print the read character.
            System.out.println("The character read = " + ch );
         }
      }catch(Exception e){
         e.printStackTrace();
      }finally{
         
         // releases any system resources associated with the stream
         if(inStream!=null)
            inStream.close();
         if(bis!=null)
            bis.close();
      }
   }
}

假设有一个文本文件c:/ test.txt，它具有以下内容。该文件将被用作输入我们的示例程序：

ABCDE 

编译和运行上面的程序，这将产生以下结果：

Available bytes = 5
The character read = A
Available bytes = 4
The character read = B
Available bytes = 3
The character read = C
Available bytes = 2
The character read = D
Available bytes = 1
The character read = E