Write file in java using PrintWriter (class hierarchy & example)

• PrintWriter writes the formatted data to output stream.
• PrintWriter provides the methods to write int, boolean, char, String, double, float etc.

Constructors of PrintWriter (Java IO)

• PrintWriter(File file)
  Creates a new PrintWriter, without automatic line flushing, with the specified file.
• PrintWriter(File file, String csn)
  Creates a new PrintWriter, without automatic line flushing, with the specified file and charset.
• PrintWriter(OutputStream out)
  Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream.
• PrintWriter(OutputStream out, boolean autoFlush)
  Creates a new PrintWriter from an existing OutputStream.
• PrintWriter(String fileName)
  Creates a new PrintWriter, without automatic line flushing, with the specified file name.
• PrintWriter(String fileName, String csn)
  Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset.
• PrintWriter(Writer out)
  Creates a new PrintWriter, without automatic line flushing.
• PrintWriter(Writer out, boolean autoFlush)
  Creates a new PrintWriter.

We will write the following kinds of data using PrintWriter:

• Integer, Double, Boolean
• String, Char, Character array and formatted data.

Program – Write file in java using PrintWriter

package org.learn.io;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class PrintWriterDemo {
 public static void main(String[] args) throws IOException {
  writeUsingPrintWriter();
 }

 private static void writeUsingPrintWriter() throws IOException {
  System.out.println("1. Start writting contents to file - PrintWriter");
  try (FileWriter fileWriter = new FileWriter(new File("sampleFile.txt"));
    PrintWriter printWriter = new PrintWriter(fileWriter)) {
   char charValue = 'A';
   boolean booleanValue = false;
   int intValue = 100;
   double doubleValue = 20.15;
   char[] charArray = "CharArray".toCharArray();
   String stringValue = "Some Value";  
   
   //Writing using PrintWriter
   printWriter.print(charValue);
   printWriter.print('.');
   printWriter.write(" Soccer");
   printWriter.println();
   printWriter.print(booleanValue);
   printWriter.println();
   printWriter.println(intValue);
   printWriter.println(doubleValue);
   printWriter.println(charArray);
   printWriter.println(stringValue);
   printWriter.format("Format - StringValue:%s, Integer:%d, char:%c",stringValue,intValue,charValue);
   printWriter.println();
   printWriter.write("Successfully demonstrated PrintWriter");
  }
  System.out.println("2. Successfully written contents to file - PrintWriter");
 } 
}

Output – Write file in java using PrintWriter

1. Start writting contents to file - PrintWriter
2. Successfully written contents to file - PrintWriter

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