How to convert Inputstream to String in Java

To convert InputStream to String, in Java, you can use BufferedReader and InputStreamReader classes.

Example

For this example will take a random string and put it into a InputStream object. Then the method getString will do all the work for our purpose: convert InputStream to String.

package com.admfactory.io;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class InputStreamToString {

    public static void main(String[] args) {
        
        /** Generate a InputStream object - can be read from a file. */
        String str = "This is a random text message.";
        InputStream is = new ByteArrayInputStream(str.getBytes());

        System.out.println("Testing InputStream to String");
        System.out.println();
        
        String result = getString(is);
        System.out.println(result);
        
        System.out.println();

    }

    /**
     * Method to convert the {@link InputStream} parameter to {@link String}
     * 
     * @param is
     *            the {@link InputStream} object
     * @return the {@link String} object returned
     */
    public static String getString(InputStream is) {
        StringBuilder sb = new StringBuilder();

        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        String line;
        try {
            while ((line = br.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            /** finally block to close the {@link BufferedReader} */
            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }
}

Output

Testing InputStream to String

This is a random text message.

References

• InputStream
• BufferedReader
• ByteArrayInputStream