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Create a FileInputStream from a String instead of a file in Java [duplicate]

Given a string:
String exampleString = "example";
How do I convert it to an InputStream?

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".

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.

You could use a StringReader and convert the reader to an input stream using the solution in this other stackoverflow post.

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);

You can try cactoos for that.
final InputStream input = new InputStreamOf("example");
The object is created with new and not a static method for a reason.

What is the fastest way to get a HTML Content using java?

I have this, but I was wondering if there is a faster way:
URL url=new URL(page);
InputStream is = new BufferedInputStream(url.openConnection().getInputStream());
BufferedReader in=new BufferedReader(new InputStreamReader(is));
String tmp="";
StringBuilder sb=new StringBuilder();
while((tmp=in.readLine())!=null){
sb.append(tmp);
}

Probably network is the biggest overhead, there isn't much you can do on Java code side. But using IOUtils is at least much faster to implement:
String page = IOUtils.toString(url.openConnection().getInputStream());
Remember to close underlying stream.

if you need manipulating with your html, find some library. Like for example jsoup.
jsoup is a Java library for working with real-world HTML. It provides
a very convenient API for extracting and manipulating data, using the
best of DOM, CSS, and jquery-like methods.
Example:
Document doc = Jsoup.connect("http://en.wikipedia.org/").get();
Elements newsHeadlines = doc.select("#mp-itn b a");

If you're using Apache Commons IO's IOUtils as Tomasz suggests, there's an even simpler method: toString(URL), or its preferred cousins that take a charset (of course that requires knowing the resource's charset in advance).
String string = IOUtils.toString( new URL( "http://some.url" ));
or
String string = IOUtils.toString( new URL( "http://some.url" ), "US-ASCII" );

Stop Jsoup from encoding

I'm trying to parese an URL with JSoup which contains the following Text: Ætterni.
After parsing the document the same string looks like that: Ætterni.
How do I prevent this form happening? I want the document 1:1 exactly like it was.
Code:
doc = Jsoup.connect(url).get();
String docEncoding=doc.outputSettings().charset().name();
OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(localLink),docEncoding);
writer.write(doc.html());
writer.close();

Use
doc.outputSettings().escapeMode(EscapeMode.xhtml);
for avoiding entities conversion.

You seem to be not utilizing the Jsoup's powers in any way. I'd just stream the HTML plain using java.net.URL. This way you have a 1:1 copy of the response.
InputStream input = new URL(url).openStream();
OutputStream output = new FileOutputStream(localLink);
// Now copy input to output the usual Java IO way.
You should not use Reader/Writer for this as this may malform the characters of sources in unknown encoding, because the platform default encoding would be used instead.

How does one create an InputStream from a String? [duplicate]

This question already has answers here:
How do I turn a String into a InputStreamReader in java?
(6 answers)
Closed 6 years ago.
I'm not used to working with streams in Java - how do I create an InputStream from a String?

Here you go:
InputStream is = new ByteArrayInputStream( myString.getBytes() );
Update For multi-byte support use (thanks to Aaron Waibel's comment):
InputStream is = new ByteArrayInputStream(Charset.forName("UTF-16").encode(myString).array());
Please see ByteArrayInputStream manual.
It is safe to use a charset argument in String#getBytes(charset) method above.
After JDK 7+ you can use
java.nio.charset.StandardCharsets.UTF_16
instead of hardcoded encoding string:
InputStream is = new ByteArrayInputStream(StandardCharsets.UTF_16.encode(myString).array());

You could do this:
InputStream in = new ByteArrayInputStream(string.getBytes("UTF-8"));
Note the UTF-8 encoding. You should specify the character set that you want the bytes encoded into. It's common to choose UTF-8 if you don't specifically need anything else. Otherwise if you select nothing you'll get the default encoding that can vary between systems. From the JavaDoc:
The behavior of this method when this string cannot be encoded in the default charset is unspecified. The CharsetEncoder class should be used when more control over the encoding process is required.

InputStream in = new ByteArrayInputStream(yourstring.getBytes());

Java 7+
It's possible to take advantage of the StandardCharsets JDK class:
String str=...
InputStream is = new ByteArrayInputStream(StandardCharsets.UTF_16.encode(str).array());

Beginning with Java 7, you can use the following idiom:
String someString = "...";
InputStream is = new ByteArrayInputStream( someString.getBytes(StandardCharsets.UTF_8) );

Instead of CharSet.forName, using com.google.common.base.Charsets from Google's Guava (http://code.google.com/p/guava-libraries/wiki/StringsExplained#Charsets) is is slightly nicer:
InputStream is = new ByteArrayInputStream( myString.getBytes(Charsets.UTF_8) );
Which CharSet you use depends entirely on what you're going to do with the InputStream, of course.

How do I convert a String to an InputStream in Java?

Given a string:
String exampleString = "example";
How do I convert it to an InputStream?

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".

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.

You could use a StringReader and convert the reader to an input stream using the solution in this other stackoverflow post.

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);

You can try cactoos for that.
final InputStream input = new InputStreamOf("example");
The object is created with new and not a static method for a reason.