[BAEL-15998] - Move articles out of core-java-io part 1

core-java-modules/core-java-networking-2/src/main/java/com/baeldung/download/FileDownload.java

@@ -0,0 +1,90 @@
+package com.baeldung.download;
+
+import org.apache.commons.io.FileUtils;
+import org.asynchttpclient.*;
+
+import java.io.*;
+import java.net.URL;
+import java.nio.channels.Channels;
+import java.nio.channels.FileChannel;
+import java.nio.channels.ReadableByteChannel;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.concurrent.ExecutionException;
+
+public class FileDownload {
+
+    public static void downloadWithJavaIO(String url, String localFilename) {
+
+        try (BufferedInputStream in = new BufferedInputStream(new URL(url).openStream()); FileOutputStream fileOutputStream = new FileOutputStream(localFilename)) {
+
+            byte dataBuffer[] = new byte[1024];
+            int bytesRead;
+            while ((bytesRead = in.read(dataBuffer, 0, 1024)) != -1) {
+                fileOutputStream.write(dataBuffer, 0, bytesRead);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static void downloadWithJava7IO(String url, String localFilename) {
+
+        try (InputStream in = new URL(url).openStream()) {
+            Files.copy(in, Paths.get(localFilename), StandardCopyOption.REPLACE_EXISTING);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static void downloadWithJavaNIO(String fileURL, String localFilename) throws IOException {
+
+        URL url = new URL(fileURL);
+        try (ReadableByteChannel readableByteChannel = Channels.newChannel(url.openStream()); 
+            FileOutputStream fileOutputStream = new FileOutputStream(localFilename); FileChannel fileChannel = fileOutputStream.getChannel()) {
+
+            fileChannel.transferFrom(readableByteChannel, 0, Long.MAX_VALUE);
+            fileOutputStream.close();
+        }
+    }
+
+    public static void downloadWithApacheCommons(String url, String localFilename) {
+
+        int CONNECT_TIMEOUT = 10000;
+        int READ_TIMEOUT = 10000;
+        try {
+            FileUtils.copyURLToFile(new URL(url), new File(localFilename), CONNECT_TIMEOUT, READ_TIMEOUT);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    public static void downloadWithAHC(String url, String localFilename) throws ExecutionException, InterruptedException, IOException {
+
+        FileOutputStream stream = new FileOutputStream(localFilename);
+        AsyncHttpClient client = Dsl.asyncHttpClient();
+
+        client.prepareGet(url)
+            .execute(new AsyncCompletionHandler<FileOutputStream>() {
+
+                @Override
+                public State onBodyPartReceived(HttpResponseBodyPart bodyPart) throws Exception {
+                    stream.getChannel()
+                        .write(bodyPart.getBodyByteBuffer());
+                    return State.CONTINUE;
+                }
+
+                @Override
+                public FileOutputStream onCompleted(Response response) throws Exception {
+                    return stream;
+                }
+            })
+            .get();
+
+        stream.getChannel().close();
+        client.close();
+    }
+
+}

core-java-modules/core-java-networking-2/src/main/java/com/baeldung/download/ResumableDownload.java

@@ -0,0 +1,62 @@
+package com.baeldung.download;
+
+import java.io.*;
+import java.net.*;
+
+public class ResumableDownload {
+
+    public static long downloadFile(String downloadUrl, String saveAsFileName) throws IOException, URISyntaxException {
+
+        File outputFile = new File(saveAsFileName);
+        URLConnection downloadFileConnection = new URI(downloadUrl).toURL()
+            .openConnection();
+        return transferDataAndGetBytesDownloaded(downloadFileConnection, outputFile);
+    }
+
+    private static long transferDataAndGetBytesDownloaded(URLConnection downloadFileConnection, File outputFile) throws IOException {
+
+        long bytesDownloaded = 0;
+        try (InputStream is = downloadFileConnection.getInputStream(); OutputStream os = new FileOutputStream(outputFile, true)) {
+
+            byte[] buffer = new byte[1024];
+
+            int bytesCount;
+            while ((bytesCount = is.read(buffer)) > 0) {
+                os.write(buffer, 0, bytesCount);
+                bytesDownloaded += bytesCount;
+            }
+        }
+        return bytesDownloaded;
+    }
+
+    public static long downloadFileWithResume(String downloadUrl, String saveAsFileName) throws IOException, URISyntaxException {
+        File outputFile = new File(saveAsFileName);
+
+        URLConnection downloadFileConnection = addFileResumeFunctionality(downloadUrl, outputFile);
+        return transferDataAndGetBytesDownloaded(downloadFileConnection, outputFile);
+    }
+
+    private static URLConnection addFileResumeFunctionality(String downloadUrl, File outputFile) throws IOException, URISyntaxException, ProtocolException, ProtocolException {
+        long existingFileSize = 0L;
+        URLConnection downloadFileConnection = new URI(downloadUrl).toURL()
+            .openConnection();
+
+        if (outputFile.exists() && downloadFileConnection instanceof HttpURLConnection) {
+            HttpURLConnection httpFileConnection = (HttpURLConnection) downloadFileConnection;
+
+            HttpURLConnection tmpFileConn = (HttpURLConnection) new URI(downloadUrl).toURL()
+                .openConnection();
+            tmpFileConn.setRequestMethod("HEAD");
+            long fileLength = tmpFileConn.getContentLengthLong();
+            existingFileSize = outputFile.length();
+
+            if (existingFileSize < fileLength) {
+                httpFileConnection.setRequestProperty("Range", "bytes=" + existingFileSize + "-" + fileLength);
+            } else {
+                throw new IOException("File Download already completed.");
+            }
+        }
+        return downloadFileConnection;
+    }
+
+}