HTTP文件的下载后台JAVA代码
1、使用org.apache.http.impl.client.CloseableHttpClient
先上代码：
public String downloadFile(String src_file, String dest_file) throws Throwable {
String fileName = getFileName(src_file);
try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
HttpGet httpget = new HttpGet(src_file);
httpget.setConfig(RequestConfig.custom() //
.setConnectionRequestTimeout(downloadTimeout) //
.setConnectTimeout(downloadTimeout) //
.setSocketTimeout(downloadTimeout) //
.build());
try (CloseableHttpResponse response = httpclient.execute(httpget)) {
org.apache.http.HttpEntity entity = response.getEntity();
File desc = new File(dest_file+File.separator+fileName);
File folder = desc.getParentFile();
folder.mkdirs();
try (InputStream is = entity.getContent(); //
OutputStream os = new FileOutputStream(desc)) {
StreamUtils.copy(is, os);
}
}catch(Throwable e){
throw new Throwable("文件下载失败......", e);
}
}
return dest_file+File.separator+fileName;
}
另外：添加header代码如下：httpget.addHeader("X-Auth-Token",token);
2、使用curl:
windows系统中使用需要下载CURL,下载地址：https://curl.haxx.se/download.html 选择windows版；
使用命令行下载文件java代码：
package com.test.download;
import java.io.IOException;
public class TestDownload {
public static void main(String[] args) {
String curlPath = "D:\\curl\\I386\\CURL.EXE";
String destPath = "D:\\2.jpg";
String fileUrl = "http://i0.hdslb.com/bfs/archive/5a08e413f479508ab78bb562ac81f40ad28a4245.jpg";
dowloadFile(curlPath,destPath,fileUrl);
}
private static void dowloadFile(String curlPath ,String filePath, String url) {
long start = System.currentTimeMillis();
String token = "12345678901234567890";
System.out.println("执行命令==="+curlPath + " -o "+ filePath +" \"" + url +"\""
+ " -H \"X-Auth-Token:"+token+"\" -X GET");
try {
Runtime.getRuntime().exec(curlPath + " -o "+ filePath +" \"" + url +"\""
+ " -H \"X-Auth-Token:"+token+"\" -X GET");
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("下载成功，耗时(ms)："+(System.currentTimeMillis()-start));
}
}
具体的CURL命令行使用可以看帮助：curl -h
3、Servlet文件下载：
public void downloadNet(HttpServletResponse response) throws MalformedURLException {
int bytesum = 0;
int byteread = 0;
URL url = new URL("http://img.baidu.com/logo.gif");
try {
URLConnection conn = url.openConnection();
InputStream inStream = conn.getInputStream();
FileOutputStream fs = new FileOutputStream("c:/abc.gif");
byte[] buffer = new byte[1204];
int length;
while ((byteread = inStream.read(buffer)) != -1) {
bytesum += byteread;
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception {
File f = new File(filePath);
if (!f.exists()) {
response.sendError(404, "File not found!");
return;
}
BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
byte[] buf = new byte[1024];
int len = 0;
response.reset(); // 非常重要
if (isOnLine) { // 在线打开方式
URL u = new URL("file:///" + filePath);
response.setContentType(u.openConnection().getContentType());
response.setHeader("Content-Disposition", "inline; filename=" + f.getName());
// 文件名应该编码成UTF-8
} else { // 纯下载方式
response.setContentType("application/x-msdownload");
response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());
}
OutputStream out = response.getOutputStream();
while ((len = br.read(buf)) > 0)
out.write(buf, 0, len);
br.close();
out.close();
}
download
4、添加两个文件复制的代码：
private static void nioTransferCopy(File source, File target) {
FileChannel in = null;
FileChannel out = null;
FileInputStream inStream = null;
FileOutputStream outStream = null;
try {
inStream = new FileInputStream(source);
outStream = new FileOutputStream(target);
in = inStream.getChannel();
out = outStream.getChannel();
in.transferTo(0, in.size(), out);
} catch (IOException e) {
e.printStackTrace();
} finally {
close(inStream);
close(in);
close(outStream);
close(out);
}
}
private static void nioBufferCopy(File source, File target) {
FileChannel in = null;
FileChannel out = null;
FileInputStream inStream = null;
FileOutputStream outStream = null;
try {
inStream = new FileInputStream(source);
outStream = new FileOutputStream(target);
in = inStream.getChannel();
out = outStream.getChannel();
ByteBuffer buffer = ByteBuffer.allocate(4096);
while (in.read(buffer) != -1) {
buffer.flip();
out.write(buffer);
buffer.clear();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
close(inStream);
close(in);
close(outStream);
close(out);
}
}
添加一个文件下载的RestTemplate的实现：
public void downloadLittleFileToPath(String url, String target) {
Instant now = Instant.now();
RestTemplate template = new RestTemplate();
ClientHttpRequestFactory clientFactory = new HttpComponentsClientHttpRequestFactory();
template.setRequestFactory(clientFactory);
HttpHeaders header = new HttpHeaders();
List<MediaType> list = new ArrayList<MediaType>();
// 指定下载文件类型
list.add(MediaType.APPLICATION_OCTET_STREAM);
header.setAccept(list);
HttpEntity<byte[]> request = new HttpEntity<byte[]>(header);
ResponseEntity<byte[]> rsp = template.exchange(url, HttpMethod.GET, request, byte[].class);
logger.info("[下载文件] [状态码] code:{}", rsp.getStatusCode());
try {
Files.write(Paths.get(target), Objects.requireNonNull(rsp.getBody(), "未获取到下载文件"));
} catch (IOException e) {
logger.error("[下载文件] 写入失败:", e);
}
logger.info("[下载文件] 完成,耗时:{}", ChronoUnit.MILLIS.between(now, Instant.now()));
}
public void downloadBigFileToPath(String url, String target) {
Instant now = Instant.now();
try {
RestTemplate template = new RestTemplate();
ClientHttpRequestFactory clientFactory = new HttpComponentsClientHttpRequestFactory();
template.setRequestFactory(clientFactory);
//定义请求头的接收类型
RequestCallback requestCallback = request -> request.getHeaders()
.setAccept(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM, MediaType.ALL));
// getForObject会将所有返回直接放到内存中,使用流来替代这个操作
ResponseExtractor<Void> responseExtractor = response -> {
// Here I write the response to a file but do what you like
Files.copy(response.getBody(), Paths.get(target));
return null;
};
template.execute(url, HttpMethod.GET, requestCallback, responseExtractor);
} catch (Throwable e) {
logger.error("[下载文件] 写入失败:", e);
}
logger.info("[下载文件] 完成,耗时:{}", ChronoUnit.MILLIS.between(now, Instant.now()));
}
RestTemplate下载文件