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author | Zhomart Mukhamejanov <zhomart@google.com> | 2018-04-27 01:10:12 +0200 |
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committer | Zhomart Mukhamejanov <zhomart@google.com> | 2018-05-01 21:08:18 +0200 |
commit | 93535dd033024f9fb9413dba56bb5fa49abcba0b (patch) | |
tree | 4cfc103302db210dee87858b05259f7bcd2a94e7 /updater_sample/src/com/example/android/systemupdatersample | |
parent | Merge "updater_sample: Improve UpdateConfig" (diff) | |
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Diffstat (limited to 'updater_sample/src/com/example/android/systemupdatersample')
-rw-r--r-- | updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java b/updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java new file mode 100644 index 000000000..806f17351 --- /dev/null +++ b/updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java @@ -0,0 +1,93 @@ +/* + * Copyright (C) 2018 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package com.example.android.systemupdatersample.util; + +import android.util.Log; + +import java.io.File; +import java.io.FileOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; +import java.net.URL; +import java.net.URLConnection; + +/** + * Downloads chunk of a file from given url using {@code offset} and {@code size}, + * and saves to a given location. + * + * In real-life application this helper class should download from HTTP Server, + * but in this sample app it will only download from a local file. + */ +public final class FileDownloader { + + private String mUrl; + private long mOffset; + private long mSize; + private File mOut; + + public FileDownloader(String url, long offset, long size, File out) { + this.mUrl = url; + this.mOffset = offset; + this.mSize = size; + this.mOut = out; + } + + /** + * Downloads the file with given offset and size. + */ + public void download() throws IOException { + Log.d("FileDownloader", "downloading " + mOut.getName() + + " from " + mUrl + + " to " + mOut.getAbsolutePath()); + + URL url = new URL(mUrl); + URLConnection connection = url.openConnection(); + connection.connect(); + + // download the file + try (InputStream input = connection.getInputStream()) { + try (OutputStream output = new FileOutputStream(mOut)) { + long skipped = input.skip(mOffset); + if (skipped != mOffset) { + throw new IOException("Can't download file " + + mUrl + + " with given offset " + + mOffset); + } + byte[] data = new byte[4096]; + long total = 0; + while (total < mSize) { + int needToRead = (int) Math.min(4096, mSize - total); + int count = input.read(data, 0, needToRead); + if (count <= 0) { + break; + } + output.write(data, 0, count); + total += count; + } + if (total != mSize) { + throw new IOException("Can't download file " + + mUrl + + " with given size " + + mSize); + } + } + } + } + +} |