How to download a file to application server java

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Viewed 37k times. In my java application I am using the following method to download files from server. How can i make it fast? The openStream function works on an object of the URL class. The URL class opens up a connection to the given URL and the openStream method returns an input stream which is used to read data from the connection. These classes are used for reading from a file and writing to it, respectively. The contents are read as bytes and copied to a file in the local directory using the FileOutputStream.

To lower the number of lines of code we can use the Files class available from Java 7. The Files class contains methods that read all the bytes at once and then copies it into another file. Here is how you can use it:. Java NIO is an alternative package to handle networking and input-output operations in Java. The main advantage that the Java NIO package offers is that it's non-blocking, and has channeling and buffering capabilities.

When we use the Java IO library we work with streams that read data byte by byte. However, the Java NIO package uses channels and buffers. The buffering and channeling capabilities allow the system to copy contents from a URL directly into the intended file without needing to save the bytes in application memory, which would be an intermediary step.

The ability to work with channels boosts performance. The downloaded contents will be transferred to a file on the local system via the corresponding file channel. Finally, we use fileChannelForDownloadedFile. There can be cases where the client need to supply some information to the HTTP server in order to download a file. As shown above, we had created a class with a main method which will propagate any occurrences of IOException back to the caller.

Given that instance, we will then be able to read from the body of the HTTP response. After we had an instance of ReadableByteChannel , we then proceed to get an instance of FileChannel that will point to a local file path where we want to save the downloaded file. In this case, we will save the downloaded file as luckyNumber. Operating System. Computer Network. Compiler Design. Computer Organization. Discrete Mathematics. Ethical Hacking. Computer Graphics. Software Engineering.

Web Technology. File; import javax. GET; import javax. Path; import javax. Produces; import javax. Response; import javax.