BufferedReader in Java

BufferedReader extends Reader. Reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.The buffer size may be specified, or the default size may be used.

Constructors

Methods

Example

package com.java.io;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;

public class BufferedReaderExample {

    public static void main(String[] args) {

        Reader reader = null;
        BufferedReader br = null;
        try {
            reader = new FileReader("/Test/TestFolder/test-file.txt");
            // Created BufferedReader with the underlying Reader
            br = new BufferedReader(reader);
            // Check if markSupported by BufferedReader
            System.out.println("Is Mark Supported:" + br.markSupported());
            if (br.markSupported()) {
                // marks the current position
                // 10 characters to be read before the mark position becomes invalid
                br.mark(10);
            }
            // Skip 5 characters of data
            br.skip(5);
            System.out.print("After Skip File Content:");
            // Checks if the stream is ready to be read
            while (br.ready()) {
                // Reading one character for each loop
                System.out.print((char) br.read());
            }
            // Resets to the earlier marked position
            br.reset();
            System.out.println("");
            System.out.print("After Reset File Content using readLine:");
            while (br.ready()) {
                // Using readLIne to read one line for each loop
                System.out.print(br.readLine());
            }
            // Resetting again to the earlier marked position
            br.reset();
            System.out.println("");
            System.out.print("Reading characters into char Array:");
            char c[] = new char[10];
            if (br.ready()) {
                br.read(c);
                for (int i = 0; i < 10; i++) {
                    System.out.print(c[i]);
                }
            }

        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            // Closing the streams
            if (reader != null)
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            if (br != null)
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }

    }

}

Output

Is Mark Supported:true
After Skip File Content:Data
After Reset File Content using readLine:Test Data
Reading characters into char Array:Test Data

Using lines to get a Stream

Reading the below file.

package com.java.io;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;

public class BufferedReaderLinesExample {

    public static void main(String[] args) {
        Reader reader = null;
        BufferedReader br = null;
        try {
            reader = new FileReader("/Test/TestFolder/test-file1.txt");
            // Created BufferedReader with the underlying Reader
            br = new BufferedReader(reader);
            if (br.ready()) {
                // Using lines
                br.lines().forEach(x - > System.out.println(x));
            }

        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            // Closing the streams
            if (reader != null)
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            if (br != null)
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
    }

}

Output

Test data1
Test data2
Test data3

Related Article

Character Stream Hierarchy in Java