如何使用Java上传大块文件？

我需要使用Java上传大块文件。

有没有我可以参考的示例代码？

Answer 1

*可以使用plupload完成。 这是样本。 我的index.html如下： –

          
 
 Select file Upload 
 
 
 

      
 我的java后端代码（Servlet）如下： –  
 import java.io.BufferedOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItemIterator; import org.apache.commons.fileupload.FileItemStream; import org.apache.commons.fileupload.servlet.ServletFileUpload; import org.apache.commons.fileupload.util.Streams; public class UploadAction extends HttpServlet { private static final long serialVersionUID = 3447685998419256747L; private static final String RESP_SUCCESS = "{\"jsonrpc\" : \"2.0\", \"result\" : \"success\", \"id\" : \"id\"}"; private static final String RESP_ERROR = "{\"jsonrpc\" : \"2.0\", \"error\" : {\"code\": 101, \"message\": \"Failed to open input stream.\"}, \"id\" : \"id\"}"; public static final String JSON = "application/json"; public static final int BUF_SIZE = 2 * 1024; public static final String FileDir = "/home/asjha/uploads/"; private int chunk; private int chunks; private String name; private String user; private String time; protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String responseString = RESP_SUCCESS; boolean isMultipart = ServletFileUpload.isMultipartContent(req); if(isMultipart){ ServletFileUpload upload = new ServletFileUpload(); try { FileItemIterator iter = upload.getItemIterator(req); while (iter.hasNext()) { FileItemStream item = iter.next(); InputStream input = item.openStream(); // Handle a form field. if(item.isFormField()){ String fileName = item.getFieldName(); String value = Streams.asString(input); if("name".equals(fileName)){ this.name = value; }else if("chunks".equals(fileName)){ this.chunks = Integer.parseInt(value); }else if("chunk".equals(fileName)){ this.chunk = Integer.parseInt(value); }else if("user".equals(fileName)){ this.user = value; }else if("time".equals(fileName)){ this.time = value; } } // Handle a multi-part MIME encoded file. else { File dstFile = new File(FileDir); if (!dstFile.exists()){ dstFile.mkdirs(); } File dst = new File(dstFile.getPath()+ "/" + this.name); saveUploadFile(input, dst); } } } catch (Exception e) { responseString = RESP_ERROR; e.printStackTrace(); } } // Not a multi-part MIME request. else { responseString = RESP_ERROR; } if(this.chunk == this.chunks - 1){ System.out.println("name"+this.name); } resp.setContentType(JSON); byte[] responseBytes = responseString.getBytes(); resp.setContentLength(responseBytes.length); ServletOutputStream output = resp.getOutputStream(); output.write(responseBytes); output.flush(); } private void saveUploadFile(InputStream input, File dst) throws IOException { OutputStream out = null; try { if (dst.exists()) { out = new BufferedOutputStream(new FileOutputStream(dst, true), BUF_SIZE); } else { out = new BufferedOutputStream(new FileOutputStream(dst), BUF_SIZE); } byte[] buffer = new byte[BUF_SIZE]; int len = 0; while ((len = input.read(buffer)) > 0) { out.write(buffer, 0, len); } } catch (Exception e) { e.printStackTrace(); } finally { if (null != input) { try { input.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != out) { try { out.close(); } catch (IOException e) { e.printStackTrace(); } } } } } 
 有关详细信息，请参阅plupload，在github上，您可以看到jakobadam和rocky的示例项目。 
 如果需要多个文件上传，请告诉我。 使用plupload我们可以上传任意数量的任何大小的文件。 此示例适用于非常大的单个文件上载。 别忘了包括plupload.full.min.js。 希望这有助于*强调文字** 

Answer 2

使用RandomAccessFile。 我已经相信这已经涵盖了。

带有rewind（）/ reset（）function的java文件输入

基本上你只是寻求起点，从那里写出你想要的许多字节，并记住你停止写的那一点。

Answer 3

您可以自己简单地破解文件，使用Socket API发送它，然后重新组装文件。

Answer 4

尝试Apache Commons上传 。 它支持流媒体，可能适合您。

Answer 5

如果您使用的是Java，请使用Arivus Nioserver gradle依赖项 – > compile’org.arivu：nioserver：1.0.3’。 没有文件大小限制。

Answer 6

以下是使用块上传文件的本机Java代码示例：

 final String LF = "\r\n"; // Line separator required by multipart/form-data. Can be static class constant final String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value. HttpURLConnection connection = (HttpURLConnection) new URL("http://some.com/upload").openConnection(); try { connection.setDoOutput(true); connection.setChunkedStreamingMode(4096); connection.setRequestMethod("POST"); connection.addRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary); connection.addRequestProperty("Accept", "application/json"); connection.addRequestProperty("Authorization", myToken); try (OutputStream os = connection.getOutputStream(); Writer writer = new OutputStreamWriter(os, StandardCharsets.UTF_8)) { writer.append("--").append(boundary).append(LF); writer.append("Content-Disposition: form-data; name=\"dataFile\"; filename=\"file.zip\"").append(LF); writer.append("Content-Type: application/zip").append(LF); writer.append(LF); writer.flush(); // Write body writeBinaryBody(os); writer.append(LF).append("--").append(boundary).append("--").append(LF); writer.flush(); os.flush(); } if (200 != connection.getResponseCode()) { try (Reader reader = new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8)) { // Handle error here } } } finally { connection.disconnect(); } 

此示例中的代码基于有关从java上传http文件的答案 。 区别在于对connection.setChunkedStreamingMode(4096);的调用connection.setChunkedStreamingMode(4096); 定义应该使用分块流。