How to read or convert an inputstream into a string in java? - Six easy ways

In many development projects, we might need to convert an InputStream into a String in java.
In this tutorial we will discuss simple and handpicked ways to read or convert an InputStream into a String in Java.
Depending upon your project configuration, you can use any of the following methods.

For the purpose of this tutorial, lets assume "inputStream" is a variable of type InputStream.

InputStream inputStream; 

Check the ways below.

1. Using Java 1.8+ inbuilt Streams package:

String result = new BufferedReader(new InputStreamReader(inputStream))
                    .lines().collect(Collectors.joining("\n"));

This method works with Java 1.8+

2. Native Java Scanner way:

try (Scanner scanner = new Scanner(inputStream).useDelimiter("\\A")) {
    String result = scanner.hasNext() ? scanner.next() : "";
}

Note that "\A" represents regex pattern for useDelimiter scanner method.
"\A" stands for :start of a string! . So when this pattern is supplied, whole stream is ready into the scanner object.

3. Apache commons-io IOUtils way:

String result = IOUtils.toString(inputStream);

For this method, Apache commons-io library should be included into your project. You can include it with the below maven
maven link.

4. Using Google Guava library:

String result = CharStreams.toString(new InputStreamReader(inputStream));

For this method, Guava library should be included into your project. You can include it with the below maven
maven link

5. Spring Boot style:

String content = StreamUtils.copyToString(inputStream, StandardCharsets.UTF_8);

If you are using spring boot framework for your project you can use this. To include spring boot, you can use the below
maven repo

6. Plain old ByteArrayOutputStream way:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) != -1) {
    baos.write(buffer, 0, length);
}
String result = baos.toString();

If you want to play around with actual InputStreams without any utility methods you can use the above style.

Bonus: How to read and write to file as a string in java in simple way : https://tipseason.com/how-to-read-file-as-string-in-java/

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