How do I convert InputStream to String?

This example will show you how to convert an InputStream to String. In the code snippet below we read a data.txt file, could be from common folder or from inside a jar file.

package org.kodejava.example.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.io.Writer;
import java.io.Reader;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class StreamToString {

    public static void main(String[] args) throws Exception {
        StreamToString sts = new StreamToString();

        //
        // Get input stream of our data file. This file can be in
        // the root of you application folder or inside a jar file
        // if the program is packed as a jar.
        //
        InputStream is =
                sts.getClass().getResourceAsStream("/data.txt");

        //
        // Call the method to convert the stream to string
        //
        System.out.println(sts.convertStreamToString(is));
    }

    public String convertStreamToString(InputStream is)
            throws IOException {
        //
        // To convert the InputStream to String we use the
        // Reader.read(char[] buffer) method. We iterate until the
        // Reader return -1 which means there's no more data to
        // read. We use the StringWriter class to produce the string.
        //
        if (is != null) {
            Writer writer = new StringWriter();

            char[] buffer = new char[1024];
            try {
                Reader reader = new BufferedReader(
                        new InputStreamReader(is, "UTF-8"));
                int n;
                while ((n = reader.read(buffer)) != -1) {
                    writer.write(buffer, 0, n);
                }
            } finally {
                is.close();
            }
            return writer.toString();
        } else {        
            return "";
        }
    }
}

Wayan Saryada

I am a programmer, a runner, an open water diver and currently living in the island of Bali, Indonesia. If you need help on Java programming you can hire me on Fiverr.

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