Java File From Website

Java file from website

How to download file from website using javascript. Java download file from website. Javascript download file from website. Download csv file from website using java. How do i download a javascript file from a website. Get javascript file from website. Get file from website java. Auto download file from website javascript.This article covers a different ways to Read and Download a File from an URL in Java and storing it on disk, which includes plain Java IO, NIO, HttpClient, and Apache Commons Library. There are a number of ways, we can download a file from a URL on internet. This article will help you understand them with the help of examples. We will begin byusing BufferedInputStream and Files.copy() methods in Plain Java. Next we will see how to achieve the same using Java NIO package. Also, we will see how to use HttpClient, which provides a Non-Blocking way of downloading a file. Finally, we will use third party library of Apache Commons IO to download a file. First, we will see an example of usingJava IO to download a file. The Java IO provides APIs to read bytes from InputStream and writing them to a File on disk. While, Java NET package provides APIs to interact with a resource residing over internet with the help of URL. In order to use Java IO and Java NET we need to use java.io.* and java.net.* packages into our class. UsingBufferedInputStream Next is a simple example of using Java IO and Java NET to read a file from URL. Here, we are using BufferedInputStream to download a file. URL url new URL(" ); try ( InputStream inputStream url.openStream(); BufferedInputStream bufferedInputStream new BufferedInputStream(inputStream); FileOutputStreamfileOutputStream new FileOutputStream(outputPath); ) { byte[] bucket new byte[2048]; int numBytesRead; while ((numBytesRead bufferedInputStream.read(bucket, 0, bucket.length)) ! -1) { fileOutputStream.write(bucket, 0, numBytesRead); } }Code language: Java (java) At first, we created an URL instance by specifying URL of the file orresource we want to download. Then, we opened an InputStream from the file using openStream method. Next, in order to be able to download large files we wrapped the input stream into a BufferedInputStream. Also, we created a FileOutputStream by providing a path on the disk where we want the file to be saved. Next, we use a bucket of byte[] toread 2048 bytes from the input stream and writing onto the output stream iteratively. This example, demonstrates how we can use our own buffer (for example 2048 bytes) so that downloading large files should not consume huge memory on our system. Note: While dealing with Java File IO, we must close all the open streams and readers. To do that,we have used try-with-resources block for respective streams instantiation. While writing the previous example, we had to take care of a lot of logic. Thankfully, Java Files class provides the copy method which handles these logic internally. Next is an example of using Files.copy() to download file from URL. URL url new URL(" "); try(InputStreaminputStream url.openStream()){ Files.copy(inputStream, Paths.get(outputPath)); }Code language: Java (java) The Java NIO package offers a faster way of data transfer, which does not buffer data in memory. Hence, we can easily work with large files. In order to use Java NIO channels, we need to create two channels. One channel will connect tothe source and other to the target. Once the channels are set, we can transfer data between them. Next is an example of using NIO Channels to read a file on internet. URL url new URL(" "); try ( ReadableByteChannel inputChannel Channels.newChannel(url.openStream()); FileOutputStream fileOutputStream newFileOutputStream(outputPath); FileChannel outputChannel fileOutputStream.getChannel(); ) { outputChannel.transferFrom(inputChannel, 0, Long.MAX VALUE); }Code language: Java (java) We can also use HttpClient provided by java NET package. Next, is an example of using HttpClient to download a file and save it on the disk. HttpClienthttpClient HttpClient.newBuilder().build(); HttpRequest httpRequest HttpRequest .newBuilder() .uri(new URI(" ")) .GET() .build(); HttpResponse response httpClient .send(httpRequest, responseInfo - HttpResponse.BodySubscribers.ofInputStream()); Files.copy(response.body(), Paths.get(outputPath));Code language: Java (java) First, wesimply create an instance of HttpClient using its builder. Next, we create HttpRequest by providing the URI, and HTTP GET method type. Then we invoke the request by attaching a BodyHandler, which returns a BodySubscriber of InputStream type. Finally, we use the input stream from the HttpResponse and use File#copy() method to write it to aPath on disk. This section explains how to asynchronously download a file from URL and save it to the disk. To do that, we can use sendAsync method of HttpClient, which will return a Future instance. When we execute an asynchronous method, the program execution will not wait for the method to finish. Instead it will progress further doing otherstuff. We can check on the future instance to see if the execution is finished and the response is ready. Next block of code demonstrates using HttpClient that downloads a file asynchronously and save onto the disk. HttpRequest httpRequest HttpRequest .newBuilder() .uri(new URI(" ")) .GET() .build(); Future futureInputStream httpClient.sendAsync(httpRequest, HttpResponse.BodyHandlers.ofInputStream()) .thenApply(HttpResponse::body); InputStream inputStream futureInputStream.get(); Files.copy(inputStream, Path.of(outputPath));Code language: Java (java) As it is shown in the example, we are sending an async request, which returns a Future of InputStream. the getmethod on the Future will be blocked until the input stream is ready. Finally, we use Files#copy method to write the file to disk. The Apache Commons IO library provides a number of useful abstractions for general purpose File IO. In order to read a file from URL and to save it to disk, we can use copyURLToFile method provided by FileUtils class.Here is an example of using Apache Commons IO to read a file from URL and save it. URL url new URL(" "); FileUtils.copyURLToFile(url, new File(outputPath));Code language: Java (java) This looks a lot simpler and short. The copyURLToFile method internally uses IOUtils.copy method (as explained in Using Apache Commons IO to copyInputStream to OutputStream). Thus, we do not need to manually read buffers from input stream and write on output stream. Alternatively, we can use another flavour of this method which allows to set connection timeout, and read timeout values. public static void copyURLToFile( URL source, File destination, int connectionTimeout, intreadTimeout) throws IOException {Code language: Java (java) The snippet shows signature of the method that we can use along with specific timeout values. In this article we understood How to Download a File from URL and store it on the disk. We have covered a different ways of doing this, which includes using Plain Java IO and Java NETcombination, using Java NIO package, using Http Client both synchronously and asynchronously, and finally using Apache Commons IO. For more on Java, please visit Java Tutorials. This post will discuss how to download a file from a URL in Java. There are several ways to download a file from a URL in Java. This post provides an overview of some ofthe available alternatives to accomplish this. 1. Using FileChannel.transferFrom() method java.nio.channels.FileChannel class in Java provides several methods for reading, writing, mapping, and manipulating a file. It is transferFrom() method transfers bytes into this channel’s file from the given readable byte channel. It accepts three parameters –the source channel, the position within the file at which the transfer is to begin, and the maximum number of bytes to be transferred. The complete usage is demonstrated below with Java 7 try-with-resource, which take care of closing the opened streams and channels: import java.io.FileOutputStream;import rt java.nio.channels.Channels;import java.nio.channels.ReadableByteChannel; public static void downloadFile(URL url, String outputFileName) throws IOExceptiontry (InputStream in url.openStream();ReadableByteChannel rbc Channels.newChannel(in);FileOutputStream fos newFileOutputStream(outputFileName)) {fos.getChannel().transferFrom(rbc, 0, Long.MAX VALUE); public static void main(String[] args) throws Exception {// call to downloadFile() method Download Code 2. Using Files.copy() method From Java 7 onward, we can use the java.nio.file.Files.copy() method to copy all bytes from an inputstream to a file. It accepts the input stream to read from and the path to the file. Additionally, we can specify how the copying should be done. This is demonstrated below using the try-with-resource block: import java.io.InputStream;import java.nio.file.Files;import java.nio.file.Paths; public static void downloadFile(URL url, String fileName) throwsException {try (InputStream in url.openStream()) {Files.copy(in, Paths.get(fileName)); public static void main(String[] args) throws Exception {// call to downloadFile() method Download Code 3. Plain Java In plain Java, we can read the file byte by byte from the input stream and write the bytes to a file output stream. Thiswould translate to a simple code below: import java.io.BufferedInputStream;import java.io.FileOutputStream;import java.io.InputStream;import java.io.IOException; public static void downloadFile(URL url, String fileName) throws IOException {try (InputStream in url.openStream();BufferedInputStream bis newBufferedInputStream(in);FileOutputStream fos new FileOutputStream(fileName)) {byte[] data new byte[1024];while ((count bis.read(data, 0, 1024)) ! -1) {fos.write(data, 0, count); public static void main(String[] args) throws Exception {// call to downloadFile() method Download Code 4. UsingApache Commons IO We can also use Apache Commons IO library, whose FileUtils class offers handy file manipulation utilities. FileUtils’s copyURLToFile() method can be used to copy bytes from the URL source to the specified file destination. It is recommended to use its overloaded version with connection and read timeout parameters. importorg.apache.commons.io.FileUtils;import java.io.IOException; public static void downloadFile(URL url, String fileName) throws IOException {FileUtils.copyURLToFile(url, new File(fileName)); public static void main(String[] args) throws Exception {// call to downloadFile() method Download Code That’s all about downloading a filefrom a URL in Java. Thanks for reading. Please use our online compiler to post code in comments using C, C , Java, Python, JavaScript, C#, PHP, and many more popular programming languages. Like us? Refer us to your friends and help us grow. Happy coding