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The function returns the number of bytes copied. If the value of the variable i is -1, then it indicates that the contents of the file are over 2GB. When the returned value is -1, you can use the function copyLarge inputStream, fileOS in place of the copy inputstream, fileOS function to handle this load. Both of these functions buffer the inputstream internally. The internal buffer means we do not have to use the BufferedInputStream class to enhance our code performance and helps us avoid writing boilerplate code.
Another library managed by the Apache organization is the HttpComponents package. This library uses the request-response mechanism to download the file from a given URL. The first step to downloading a file is to create an HTTP client object that would issue the request to the server.
For this, we will be using the CloseableHttpClient class. The code snippet that creates a new HTTP client is as follows:. We then need to create an HttpGet or HttpPost object to send the request to the server. The request is created by the following line of code:. The execute request function is applied to the client object and returns with a response from the server.
Once the request is sent to the server we need a response object to receive the data sent from the server. To catch the response from the server we use the HttpResponse class object. The data sent by the server in the form of a message is obtained through the getEntity function. You can also obtain the response code sent by the server through the response object and use it to your specific need. The data to be downloaded is encapsulated within the entity object and can be extracted using the getContent function.
The getContent function returns an InputStream object that can be further used with a BufferedInputStreamReader to enhance performance. Now all you need to do is read from the stream byte by byte and write the contents into a file using the FileOutputStream class. The last thing required to be done is closing all the open resources in order to ensure that the system resources are not overutilized and that there are no memory leaks. So there you have it - these are the simplest ways to download a file using the basic Java code and other third party libraries.
If any found then those file object will be taken from request. We are writing the file using write method of the fileobject into the folder which has been mentioned. Code Line Forwarding request using requestdispatcher object to result. Code Line Here we are getting the attribute from the request object with value gurumessage into a string object.
We get a form wherein there is fields to choose a file from directory. Once the file is selected then we have to click on the upload button. Code Line As we have defined a href, which will be enclosed in URL so GET method will get processed doGet will be called in servlet which also encloses request and response objects. Code Line We are setting content Type in response object and also get writer object from response. Code Line Defining a variable as gurufile as value test. Code Line We are setting the content type using response object and we use setHeader method which sets header into the response object as the filename which has been uploaded.
Code Line Here we have taken a while loop which will run till the file is read,hence we have given condition as!
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