Java Read Write UTF-8 Encoded File

Many times we need to deal with the UTF-8 encoded file in our application. This may be due to localization needs or simply processing user input out of some requirements.

Even some data sources may provide data in UTF-8 format only. In this Java tutorial, we will learn two very simple examples of reading and writing UTF-8 content from a file.

1. Writing UTF-8 Encoded Data into a File

The given below is a Java example to demonstrate how to write “UTF-8” encoded data into a file. It uses the character encoding “UTF-8” while creating the OutputStreamWriter.

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.nio.charset.StandardCharsets;

public class WriteUTF8Data
{
   public static void main(String[] args)
   {
      try
      {
         File fileDir = new File("c:\\temp\\test.txt");

         Writer out = new BufferedWriter(new OutputStreamWriter
                           (new FileOutputStream(fileDir), StandardCharsets.UTF_8));

         out.append("Howtodoinjava.com").append("\r\n");
         out.append("UTF-8 Demo").append("\r\n");
         out.append("क्षेत्रफल = लंबाई * चौड़ाई").append("\r\n");

         out.flush();
         out.close();
      } catch (UnsupportedEncodingException e)
      {
         System.out.println(e.getMessage());
      } catch (IOException e)
      {
         System.out.println(e.getMessage());
      } catch (Exception e)
      {
         System.out.println(e.getMessage());
      }
   }
}

2. Reading UTF-8 Encoded File

We need to pass StandardCharsets.UTF_8 into the InputStreamReader constructor to read data from a UTF-8 encoded file.

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

public class ReadUTF8Data
{
   public static void main(String[] args)
   {
      try {
         File fileDir = new File("c:\\temp\\test.txt");
  
         BufferedReader in = new BufferedReader(
            new InputStreamReader(
                       new FileInputStream(fileDir), "UTF8"));
  
         String str;
  
         while ((str = in.readLine()) != null) {
             System.out.println(str);
         }
  
                 in.close();
         } 
         catch (UnsupportedEncodingException e) 
         {
             System.out.println(e.getMessage());
         } 
         catch (IOException e) 
         {
             System.out.println(e.getMessage());
         }
         catch (Exception e)
         {
             System.out.println(e.getMessage());
         }
   }
}

Program Output:

Howtodoinjava.com
UTF-8 Demo
क्षेत्रफल = लंबाई * चौड़ाई

Happy Learning !!