Given a string:
String exampleString = "example";
How do I convert it to an InputStream?
5 Answers
Like this:
InputStream stream = new ByteArrayInputStream(exampleString.getBytes(StandardCharsets.UTF_8));
Note that this assumes that you want an InputStream that is a stream of bytes that represent your original string encoded as UTF-8.
For versions of Java less than 7, replace StandardCharsets.UTF_8 with "UTF-8".
6 Comments
Jonathan Ramos
Doesn't this charset get lost when doing: String --> bytes --> ByteArrayInputStream ? When trying this on a for example "ü", the bytes will have the right letter, but the ByteArrayInputStream will have lost the right conversion. Or am I wrong?
Nantoka
StandardCharsets requires minimum API level 19.
Cruncher
@JonathanRamos it's not up to the stream to hold the conversion. It's up to whatever is decoding the bytes back into strings.
PJ_Finnegan
@Nantoka Instead of StandardCharsets.UTF_8 you can use Charset.forName("UTF-8") for any API Level.
Dave Moten
Not pretty if you have large string objects and want to save on memory/allocations. A proper streaming solution would be nice.
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I find that using Apache Commons IO makes my life much easier.
String source = "This is the source of my input stream";
InputStream in = org.apache.commons.io.IOUtils.toInputStream(source, "UTF-8");
You may find that the library also offer many other shortcuts to commonly done tasks that you may be able to use in your project.
7 Comments
Pankaj Kumar
They used new ByteArrayInputStream(exampleString.getBytes("UTF-8")). So it will be optimized way to use InputStream stream = new ByteArrayInputStream(exampleString.getBytes("UTF-8"));
Andrew White
@PankajKumar: Java's JIT compiler is more than able to inline this.
arkon
Using a method which doesn't specify encoding is a terrible idea...
Cuga
@b1naryatr0phy: Apache commons includes another form of this method which takes the encoding as a second parameter (which, you're right, is preferable): InputStream in = IOUtils.toInputStream(source, "UTF-8");
douglaslps
You can use
StandardCharsets.UTF_8 definition instead of plain text. |
You could use a StringReader and convert the reader to an input stream using the solution in this other stackoverflow post.
Comments
There are two ways we can convert String to InputStream in Java,
- Using ByteArrayInputStream
Example :-
String str = "String contents";
InputStream is = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
- Using Apache Commons IO
Example:-
String str = "String contents"
InputStream is = IOUtils.toInputStream(str, StandardCharsets.UTF_8);
2 Comments
soMuchToLearnAndShare
Hi @anil do you have opinion /experience which one is better?
Anil Nivargi
my opinion, using Apache commons IO is better option