1 使用 JAVA IO
try (BufferedInputStream in = new BufferedInputStream(new URL(LARGE_FILE_URL).openStream());
FileOutputStream fileOutputStream = new FileOutputStream(DOWNLOAD_LOCAL_FILENAME)) {
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();
}
2 使用 JAVA7 IO
try (InputStream in = new URL(LARGE_FILE_URL).openStream()) {
Files.copy(in, Paths.get(DOWNLOAD_LOCAL_FILENAME), StandardCopyOption.REPLACE_EXISTING);
} catch (IOException e) {
e.printStackTrace();
}
3 使用 JAVA NIO
URL url = new URL(LARGE_FILE_URL);
try (ReadableByteChannel readableByteChannel = Channels.newChannel(url.openStream());
FileOutputStream fileOutputStream = new FileOutputStream(DOWNLOAD_LOCAL_FILENAME);
FileChannel fileChannel = fileOutputStream.getChannel()) {
fileChannel.transferFrom(readableByteChannel, 0, Long.MAX_VALUE);
}
4 使用 ApacheCommons
4.1 依赖
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>
4.2 示例代码
int CONNECT_TIMEOUT = 10000;
int READ_TIMEOUT = 10000;
try {
FileUtils.copyURLToFile(
new URL(LARGE_FILE_URL),
new File(DOWNLOAD_LOCAL_FILENAME),
CONNECT_TIMEOUT,
READ_TIMEOUT);
} catch (IOException e) {
e.printStackTrace();
}
5 使用 Jodd-http
5.1 依赖
<dependency>
<groupId>org.jodd</groupId>
<artifactId>jodd-http</artifactId>
<version>5.1.4</version>
</dependency>
5.2 示例代码
jodd.http.HttpResponse response = HttpRequest.get(LARGE_FILE_URL).send();
byte[] bytes = response.bodyBytes();
FileUtils.writeByteArrayToFile(new File(DOWNLOAD_LOCAL_FILENAME), bytes);
6 使用 httpclient4
6.1 依赖
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.12</version>
</dependency>
6.2 示例代码
CloseableHttpClient client = HttpClientBuilder.create().build();
HttpGet request = new HttpGet(LARGE_FILE_URL);
HttpResponse response = client.execute(request);
HttpEntity entity = response.getEntity();
try (InputStream is = entity.getContent()) {
FileUtils.copyInputStreamToFile(is, new File(DOWNLOAD_LOCAL_FILENAME));
}
client.close();
7 使用 async-http-client
7.1 依赖
<dependency>
<groupId>org.asynchttpclient</groupId>
<artifactId>async-http-client</artifactId>
<version>2.12.1</version>
</dependency>
7.2 示例代码
FileOutputStream stream = new FileOutputStream(DOWNLOAD_LOCAL_FILENAME);
AsyncHttpClient client = Dsl.asyncHttpClient();
client
.prepareGet(LARGE_FILE_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();
本文使用 mdnice 排版
