The Buffered Streams BufferedReader

Reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.

In general, each read request made of a Reader causes a corresponding read request to be made of the underlying character or byte stream. It is therefore advisable to wrap a BufferedReader around any Reader whose read() operations may be costly, such as FileReaders and InputStreamReaders. For example,

 BufferedReader in = new BufferedReader(new FileReader("foo.in"));

BufferedReader class Constructors

• BufferedReader(Reader in) - Creates a buffering character-input stream that uses a default-sized input buffer.
• BufferedReader(Reader in, int sz) - Creates a buffering character-input stream that uses an input buffer of the specified size.

BufferedReader class Methods

• void close() - Closes the stream and releases any system resources associated with it.
• Stream lines() - Returns a Stream, the elements of which are lines read from this BufferedReader.
• void mark(int readAheadLimit) - Marks the present position in the stream.
• boolean markSupported() - Tells whether this stream supports the mark() operation, which it does.
• int read() - Reads a single character.
• int read(char[] cbuf, int off, int len) - Reads characters into a portion of an array.
• String readLine() - Reads a line of text.
• boolean ready() - Tells whether this stream is ready to be read.
• void reset() - Resets the stream to the most recent mark.
• long skip(long n) - Skips characters.

BufferedReader class Example

This program reads a text file named "sample.txt" and print output to console. The "sample.txt" contains below text in it.

This is the text content

import java.io.BufferedReader;

import java.io.FileReader;
import java.io.IOException;

/**
 * The class demonstrate the usage of BufferedReader class methods.
 * @author javaguides.net
 *
 */
public class BufferedReaderExample {
	public static void main(String[] args) {
		try (FileReader fr = new FileReader("sample.txt");
				BufferedReader br = new BufferedReader(fr);) {
			String sCurrentLine;

			while ((sCurrentLine = br.readLine()) != null) {
				System.out.println(sCurrentLine);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

Output:

This is the text content