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

Leave a Comment / By Yogesh / May 17, 2016

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.

File read write StringWriter stringReader — Fig 1: Writing content to file

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