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Java provides several mechanisms in order to read from a file. One important class that helps in performing this operation is the BufferedReader. So, this article on BufferedReader in Java will help you in understanding Bufferedreader class along with examples. Following are the topics covered in this blog:
- What is BufferedReader in Java?
- BufferedReader Class Declaration
- Java BufferedReader Constructors
- Methods & Description
- Difference Between Scanner and BufferReader
What is BufferedReader in Java?
BufferedReader is a Java class that reads text from the input stream. It buffers the characters so that it can get the efficient reading of characters, arrays, etc. It inherits the reader class and makes the code efficient since we can read the data line-by-line with the readline() method. There are a few pointers we have to keep in mind while working with BufferedReader class in Java.
- We may have to specify the buffer size even though the default is large enough for any purpose.
- With each request made of a reader a corresponding, a read request is also made of an underlying character.
- It is always advised to wrap a BufferedReader class around any reader such as InputStreamReaders.
- For the programs that use DataInputaStreams for textual input, an appropriate BufferedReader replaces the DataInputStream to localize it.
BufferedReader Class Declaration
public class BufferedReader extends Reader
Java BufferedReader Constructors
| Constructor | Description |
BufferedReader(Reader reader) | This constructor creates a buffering character-input stream that works on a default-size input buffer. |
BufferedReader(Reader reader, int size) | It uses the specified size for the input buffer for buffering the character-input stream. |
Methods And Description
Following are the methods with the description that we have for the Java BufferedReader class.
| Method | Description |
int read() | Reads a single character |
String readLine() | It reads a line of text |
void reset() | Repositions the stream to the position where the mark method was last called |
int read(char[] cb, int off , int len) | Reads the characters in a portion of an array |
boolean markSupported() | It tests the input stream support for reset and mark method |
boolean ready() | It checks whether the input stream is ready for reading |
long skip(long n) | skips the characters |
void close() | It closes the input stream |
void mark(int readAheadLimit) | Used to mark the current position in the stream |
Example:
import java.io.*;
public class Example{
public static void main(String args[] throws Exception)
{
FileReader f = new FileReader("filelocation");
BufferedReader b = new BufferedReader(f);
int i ;
while((i = b.read()) != -1){
System.out.println((char) i);
}
b.close();
f.close();
Difference Between Scanner And BufferedReader
| BufferedReader | Scanner |
Synchronous and should be used with multiple threads | Not synchronous and not used with multiple threads |
Buffer memory is larger | Buffer memory is smaller |
Faster than Scanner | Slower because it does parsing of the input data |
There is no ambiguity related to nextline() method | There are a lot of problems with the nextline() method. |
Uses buffering to read characters from the character-input stream | It is a simple text scanner which parses primitive types and strings |
BufferedReader in JDK7 Example
import java.io.*;
public class Example{
public static void main(String[] args){
try( BufferedReader b = new BufferedReader(new fileReader("filename")));
{
String s;
while((s = b.readLine()) != null){
System.out.println(s);
}
}
catch(IOException e)
{
e.printStackTrace();
}
}
}
Reading Data From Console By InputStreamReader And BufferedReader in Java
import java.io.*;
public class Example{
public static void main(String args[] throws Exception){
InputStreamReader i = new InputStreamReader(system.in);
BufferedReader b = new BufferedReader(i);
System.out.println("Enter Course");
String course = b.readLine();
System.out.pritln("Edureka" + course);
}
}
Output:Enter Course
Java
Edureka JavaReading Data From Console Until User Writes Stop
import java.io.*;
public class Example{
public static void main(String args[] throws Exception){
InputStreamReader i = new InputStreamReader(system.in);
BufferedReader b = new BufferedReader(i);
string course = "";
while(!name.equals("stop")){
System.out.println("enter course:");
course = b.readLine();
System.out.println("Course is:" + course);
}
b.close();
i.close();
}
}
Output: enter course:
Course is: Java
enter course:
Course is: stopThis brings us to the end of this article where we have learned how we can read characters from the character-input stream using the BufferedReader class in Java. Hope you are clear with all that has been shared with you in this tutorial.
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