File read write IO operation in java – StringWriter/StringReader (example)

• We will discuss file IO operations (read and write) using StringReader and StringWriter.

File IO operation in java (StringReader and StringWriter)

• StringWriter is used to write contents as a String
• StringReader is used to read contents as a String.
• We have shown content writing using StringWriter in Fig 1.

Code: Read write file in java – StringWriter & StringReader

package org.learn.io;

import java.io.FileWriter;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;

public class StringReaderWriter {
 public static void main(String[] args) throws IOException {
  String contentWriten = writeUsingStringWriter();
  readUsingStringReader(contentWriten);
 }

 private static String writeUsingStringWriter() throws IOException {
  String contentWritten = "";
  String newLine = System.getProperty("line.separator");
  try (FileWriter fileWriter = new FileWriter("sampleFile.txt");
    StringWriter stringWriter = new StringWriter()) {
   stringWriter.write("Soccer");
   stringWriter.write(newLine);
   stringWriter.write("Tennis");
   stringWriter.write(newLine);
   stringWriter.write("Badminton");
   stringWriter.write(newLine);
   stringWriter.write("Hockey");
   stringWriter.write(newLine);
   contentWritten = stringWriter.toString();
   fileWriter.write(contentWritten);
   System.out.println("Writing content using StringWriter:");
   System.out.println(contentWritten);
  }
  return contentWritten;
 }

 private static void readUsingStringReader(String content) throws IOException {
  System.out.println("Reading content using StringReader:");
  try (StringReader stringReader = new StringReader(content)) {
   int ch;
   while ((ch = stringReader.read()) != -1)
    System.out.printf("%c", ch);
  }
 }
}

Output – read write file using StringWriter & StringReader

Writing content using StringWriter:
Soccer
Tennis
Badminton
Hockey

Reading content using StringReader:
Soccer
Tennis
Badminton
Hockey