int read(byte b)


描述

所述java.io.FilterInputStream.read(byte [] b)方法最多读取b.length个从该滤波器的输入的流数据的入字节的阵列。此方法将阻止输入数据可用。

声明

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

public int read(byte[] b)

参数

b - 目标缓冲区。

返回值

该方法返回读入缓冲区的总字节数,如果没有更多数据要读取,则返回-1。

异常

IOException - 如果发生I / O错误

实例

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

package com.tutorialspoint;

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,它具有以下内容。此文件将用作示例程序的输入

ABCDEF

让我们编译并运行上面的程序,这将产生以下结果

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