Java.io.BufferedInputStream.read() Method

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Description

The java.io.BufferedInputStream.read(byte[] b, int off, int len) method reads len bytes from byte-input stream into a byte array, starting at a given offset. This method repeatedly invokes the read() method of the underlying stream.

The iterated read continues until one of the follwing conditions becomes true:

• len bytes read.
• Returns -1, indicating end-of-file.
• If the available() method of BufferedInputStream returns 0

Declaration

Following is the declaration for java.io.BufferedInputStream.read(byte[] b, int off, int len) method

public int read(byte[] b, int off, int len)

Parameters

• b - byte array to be populated.

• off - starts storing from the offset.

• len - number of bytes to read.

Return Value

This method does not return any value.

Exception

• IOException -- if an I/O error occurs.

Example

The following example shows the usage of java.io.BufferedInputStream.read(byte[] b, int off, int len) method.

package com.tutorialspoint;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
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 number of bytes available
         int numByte = bis.available();
         
         // byte array declared
         byte[] buf = new byte[numByte];
         
         // read byte into buf , starts at offset 2, 3 bytes to read
         bis.read(buf, 2, 3);
         
         // for each byte in buf
         for (byte b : buf) {
            System.out.println((char)b+": " + b);
         }
         }catch(Exception e){
            e.printStackTrace();
         }finally{
            // releases any system resources associated with the stream
            if(inStream!=null)
               inStream.close();
            if(bis!=null)
               bis.close();
      }	
   }
}

Assuming we have a text file c:/test.txt, which has the following content. This file will be used as an input for our example program:

ABCDE  

Let us compile and run the above program, this will produce the following result:

  : 0
  : 0
A: 65
B: 66
C: 67

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