Understanding Java Writer Class

In  this  tutorial ,  We  will learn  about  writer Class  in  java. Writer  is an abstract  class  that  defines  streaming  character  output. All  of the methods in this  class return  a void value  and  throw  an  IOException  in the  case  of errors.

• The ‘Writer’ class  provides  a common set  of methods for writing  character  data to different  output destinations,such as files,  network connection, or in-memory buffers.
• It follows a character oriented approach, allowing  you to write characters,strings, and character arrays.

Subclasses  of  writer

In order to use the functionality of the  writer, we can use its subclasses. Some of them are:

1. BufferedWriter : This class  wrap around another writer and adds buffering  functionality,which can improve the performance when writing large amounts of data.
2. OutputStreamWriter : This class  is a bridge between  character  streams and byte streams. It converts character data into byte data using a specified character encoding.
3. FileWriter  : This class is used to write character data to a file. It extends the ‘Writer’ class and provides methods specifically  for writring to files.
4. PrintWriter :  This  class provides methods for writing formatted representations of objects to a text output stream.

Methods  of  Writer

The  writer  class provides different methods that are implemented by its subclasses. Here are some commonly used  methods:

• Write(int c)  :  This method writes a single character to the output stream. It takes an integer value as the parameter,which represents the unicode value of the character to be written.
• Write(char[] cbuf)  :  This  method writes an array of characters to the output stream.It  takes a character as the parameter .
• Write(String str) :  This method writes a string to the output stream . It takes string  as the parameter.
• flush()  :  This method flushes the output  stream, ensuring that  any buffered data is written immediately.
• close()  :  This method closes the output stream. It not only flushes  any buffered data but also releases any system resources asociated with the stream.

writer class in java

Example for Writer class in  java

import java.io.FileWriter;
import java.io.IOException;
public class WriterClassEmp
{
public static void main(String[] args)
{
try
{
FileWriter writer = new FileWriter("demo.txt");
writer.write("Hello, World!");
writer.close();
System.out.println("Data written into file successfully");
}
catch(IOException e)
{
System.out.println("An error occurred while writing to file");
e.printStackTrace();
}
}
}

Output : An error occurred  while writing to file

In the above example, we create a “FileWriter” object  named “writer” and specify  the files name as “demo.txt”.We  then use the “write()”  method to write the text “Hello, World!” to  the file.

Finally,we close the “FileWriter” using the “close()” method to ensure that all the data is flushed and the file is closed.