Java - FileWriter Class


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This class inherits from the OutputStreamWriter class. The class is used for writing streams of characters.

This class has several constructors to create required objects. Below given is the list of them

SR.NO Constructors and Description
1 FileWriter(File file)

This constructor creates a FileWriter object given a File object.

2 FileWriter(File file, boolean append)

This constructor creates a FileWriter object given a File object. with a boolean indicating whether or not to append the data written.

3 FileWriter(FileDescriptor fd)

This constructor creates a FileWriter object associated with the given file descriptor.

4 FileWriter(String fileName)

This constructor creates a FileWriter object, given a file name.

5 FileWriter(String fileName, boolean append)

This constructor creates a FileWriter object given a file name with a boolean indicating whether or not to append the data written.

Once you have FileWriter object in hand, then there is a list of helper methods, which can be used manipulate the files.

SN Methods with Description
1 public void write(int c) throws IOException

Writes a single character.

2 public void write(char [] c, int offset, int len)

Writes a portion of an array of characters starting from offset and with a length of len.

3 public void write(String s, int offset, int len)

Write a portion of a String starting from offset and with a length of len.

Example:

Following is the example to demonstrate class:

import java.io.*;

public class FileRead{

   public static void main(String args[])throws IOException{

      File file = new File("Hello1.txt");
      // creates the file
      file.createNewFile();
      // creates a FileWriter Object
      FileWriter writer = new FileWriter(file); 
      // Writes the content to the file
      writer.write("This\n is\n an\n example\n"); 
      writer.flush();
      writer.close();

      //Creates a FileReader Object
      FileReader fr = new FileReader(file); 
      char [] a = new char[50];
      fr.read(a); // reads the content to the array
      for(char c : a)
          System.out.print(c); //prints the characters one by one
      fr.close();
   }
}

This would produce the following result:

This
is
an
example

java_files_io.htm

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