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. Following is a list.

Sr.No. Constructor & 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 to manipulate the files.

Sr.No. Method & 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 an 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 will produce the following result −

Output

This
is
an
example

java_files_io.htm

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