Java create and download file






















The code does not give any exceptions but it does not prompt user to download anything either. 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. Asked 5 years, 6 months ago. Active 2 years, 2 months ago. Viewed 19k times. Please help me find what is wrong in the code. Following is the source code of my action class.. Improve this question. Roman C Bhugy Bhugy 2 2 gold badges 8 8 silver badges 22 22 bronze badges. Add a comment. 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. After defining the file channel we will use the transferFrom method to copy the contents read from the readChannel object to the file destination using the writeChannel object. The transferFrom and transferTo methods are much more efficient than working with streams using a buffer.

The transfer methods enable us to directly copy the contents of the file system cache to the file on the system. Thus direct channeling restricts the number of context switches required and enhances the overall code performance. Now, in the following sections, we will be looking at ways to download files from a URL using third-party libraries instead of core Java functionality components.

Now you may be thinking why would we use this when Java has its own set of libraries to handle IO operations. Here object of FileOutputStream class is created and as parameter, file path and name are given to the constructor.

You can change it as per need. The object of FileOutputStream class is necessary to call methods provided in its class. For example, if the user wants to store some text in newly created file programmatically then, write method is helpful. Because, readLine method generates exception. So to handle that exception try, catch block is used. Output: It will be the same as the previous one because just the approach to create a new file has changed the rest of the file name and the directory where it is added remains the same.

Added file name : newFile. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use , cookie and privacy policy.

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