Java.io.Reader.read() Method

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Description

The java.io.Reader.read(char[] cbuf,int off,int len) method reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Declaration

Following is the declaration for java.io.Reader.read() method.

public abstract int read(char[] cbuf,int off,int len)

Parameters

• cbuf − Destination buffer.

• off − Offset at which to start storing characters.

• len − Maximum number of characters to read.

Return Value

This method returns the number of characters read, or -1 if the end of the stream has been reached.

Exception

IOException − If the stream does not support mark(), or if some other I/O error occurs.

Example

The following example shows the usage of java.io.Reader.read() method.

package com.tutorialspoint;

import java.io.*;

public class ReaderDemo {
   public static void main(String[] args) {
      String s = "Hello world";

      // create a StringReader
      Reader reader = new StringReader(s);

      // create a char array to read chars into
      char cbuf[] = new char[5];

      try {
         // read characters into a portion of an array.
         System.out.println("" + reader.read(cbuf, 0, 5));

         // print cbuf
         System.out.println(cbuf);

         // close the stream 
         reader.close();

      } catch (IOException ex) {
         ex.printStackTrace();
      }
   }
}

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

5
Hello