How to download external files from server java

Data Science. Angular 7. Machine Learning. Data Structures. Operating System. Computer Network. Compiler Design. Computer Organization. Discrete Mathematics. Ethical Hacking. Computer Graphics. Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. This code transfers a URL content to a file without any 3rd party library.

So then you should search the reason outside the JVM. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Download file from server in java Ask Question. Asked 8 years, 3 months ago. The most easily available and a basic package available for downloading a file from internet using Java code is the Java IO package. Here we will be using the BufferedInputStream and the URL classes to open and read a file on a given address to a file on our local system.

The reason we use the BufferedInputStream class instead of the InputStream is its buffering ability that gives our code a performance boost. Before we dive deeper into the coding aspect let's take an overview of the classes and the individual functions we will be using in the process. The java. URL class in Java is a built-in library that offers multiple methods to access and manipulate data on the internet.

In this case, we will be using the openStream function of the URL class. The method signature for the openStream function is:. 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. 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. Clivant a. He owns techcoil. IOException; import java.