I'm fairly new to Java, so this may seem obvious to some. I've worked a lot with ActionScript, which is very much event based and I love that. I recently tried to write a small bit of Java code that does a POST request, but I've been faced with the problem that it's a synchronous request, so the code execution waits for the request to complete, time out or present an error.
How can I create an asynchronous request, where the code continues the execution and a callback is invoked when the HTTP request is complete? I've glanced at threads, but I'm thinking it's overkill.
Best Answer
If you are in a JEE7 environment, you must have a decent implementation of JAXRS hanging around, which would allow you to easily make asynchronous HTTP request using its client API.
This would looks like this:
Of course, this is just using futures. If you are OK with using some more libraries, you could take a look at RxJava, the code would then look like:
And last but not least, if you want to reuse your async call, you might want to take a look at Hystrix, which - in addition to a bazillion super cool other stuff - would allow you to write something like this:
For example:
Calling this command would look like:
PS: I know the thread is old, but it felt wrong that no ones mentions the Rx/Hystrix way in the up-voted answers.