Java InputStreamReader read(char[] cbuf, int offset, int length) method example

public int read(char[] cbuf, int offset, int length)
throws IOException

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

Requires Java 1.2 and up

Below is a java code demonstrates the use of read(char[] cbuf, int offset, int length) method of InputStreamReader class. The example presented might be simple however it shows the behaviour of the read(char[] cbuf, int offset, int length) method of InputStreamReader class.

package com.javatutorialhq.java.examples;


import java.io.IOException;
import java.io.InputStreamReader;

/*
 * This example source code demonstrates the use of  
 * read(char[] cbuf, int offset, int length) method 
 * of InputStreamReader class
 */

public class InputStreamReaderReadCbufOffsetExample {
	// make sure to mark this as static
	static InputStreamReader is=null;

	public static void main(String[] args) {		
		// ask for user first name as console input
		System.out.print("Enter FirstName:");	
		
		// get the console input as String variable
		String firstName=getValue();
		
		// ask for user last name as console input
		System.out.print("Enter LastName:");
		
		// get the console input as String variable
		String lastName=getValue();
		
		// display a welcome message
		System.out.println("Welcome "+firstName+" "+lastName);
		try {
			// closing the inputStreamReader
			is.close();
		} catch (IOException e) {
			e.printStackTrace();
		}

	}
	public static String getValue(){
		// initialize a InputStreamReader
		is = new InputStreamReader(System.in);
		
		// initialize placeholder variable
		char[] buffer=new char[100];
		
		// initialize return string value
		String value="";
		try {
			// read console input
			// the reader starts getting character at index 0
			// and the length of which is defined by the index size
			// of the buffer
			is.read(buffer, 0, buffer.length); // be careful for exception
			
			// since the buffer contains blank spaces
			// we have to filter it out
			for(char cbuf:buffer){
				// filter for blank space
				if((int)cbuf!=0 && (int)cbuf!=10 && (int)cbuf!=13){					
					value=value+cbuf;
				}
				
			}
		} catch (IOException e) {

			e.printStackTrace();
		}
		return value;
	}

}

Below is the sample output when you run the above example.

• Java InputStreamReader Class Tutorial
• Java Tutorial

• Oracle Java Documentation