HTTP文件下载JAVA后台的实现
Posted 凉城
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了HTTP文件下载JAVA后台的实现相关的知识,希望对你有一定的参考价值。
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(); }
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())); }
以上是关于HTTP文件下载JAVA后台的实现的主要内容,如果未能解决你的问题,请参考以下文章