Java Java.io.FilterInputStream.read() 方法

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  描述

  java.io.FilterInputStream.read(byte[] b)方法从此过滤器输入流中读取最多b.length个数据到字节数组中。该方法将阻塞，直到输入数据可用为止。
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  声明

  以下是java.io.FilterInputStream.read(byte[] b)方法的声明-

   public int read(byte[] b)

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  参数

  b目标缓冲区。
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  返回值

  该方法返回读入缓冲区的总字节数；如果没有更多要读取的数据，则返回-1。
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  异常

  IOException如果发生I / O错误
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  例子

  以下示例显示java.io.FilterInputStream.read（byte [] b）方法的用法。

   
  package com.jc2182;
  import java.io.BufferedInputStream;
  import java.io.FileInputStream;
  import java.io.FilterInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  public class FilterInputStreamDemo {
     public static void main(String[] args) throws Exception {
        InputStream is = null; 
        FilterInputStream fis = null;
        int i = 0;
        char c;
        byte[] buffer = new byte[6];
        
        try {
           // create input streams
           is = new FileInputStream("C://test.txt");
           fis = new BufferedInputStream(is);
           
           // returns number of bytes read to buffer
           i = fis.read(buffer);
           
           // prints
           System.out.println("Number of bytes read: "+i);
           
           // for each byte in buffer
           for(byte b:buffer) {
           
              // converts byte to character
              c = (char)b;
              
              // prints
              System.out.println("Character read: "+c);
           }
           
        } catch(IOException e) {
           // if any I/O error occurs
           e.printStackTrace();
        } finally {
           // releases any system resources associated with the stream
           if(is!=null)
              is.close();
           if(fis!=null)
              fis.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-

   
  Number of bytes read: 6
  Character read: A
  Character read: B
  Character read: C
  Character read: D
  Character read: E
  Character read: F