我需要使用 Java 分块上传一个大文件。
是否有我可以参考的示例代码？
*可以使用上传来完成。这是示例。我的索引.html如下：-
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<title>Upload</title>
<!-- production -->
<script type="text/javascript" src="js/plupload.full.min.js"></script>
<!-- debug
<script type="text/javascript" src="../js/moxie.js"></script>
<script type="text/javascript" src="../js/plupload.dev.js"></script>
-->
</head>
<body style="font: 13px Verdana; background: #eee; color: #333">
<div id="filelist"></div>
<br />
<button id="pickfiles" >Select file</button>
<button id="uploadfiles" >Upload</button>
<div id="container">
</div>
<br />
<pre id="console"></pre>
<script type="text/javascript">
// Custom example logic
var uploader = new plupload.Uploader({
runtimes : 'html5',
browse_button : 'pickfiles', // you can pass an id...
container: document.getElementById('container'), // ... or DOM Element itself
url : 'UploadAction',//upload.php
chunk_size : '1mb',
method:'POST',
flash_swf_url : 'js/Moxie.swf',
silverlight_xap_url : 'js/Moxie.xap',
filters : {
max_file_size : '100gb',
mime_types: [
{title : "Image files", extensions : "jpg,gif,png"},
{title : "Zip files", extensions : "zip,txt,vmdk"}
]
},
init: {
PostInit: function() {
document.getElementById('filelist').innerHTML = '';
document.getElementById('uploadfiles').onclick = function() {
uploader.start();
return false;
};
},
FilesAdded: function(up, files) {
plupload.each(files, function(file) {
document.getElementById('filelist').innerHTML += '<div id="' + file.id + '">' + file.name + ' (' + plupload.formatSize(file.size) + ') <b></b></div>';
});
},
UploadProgress: function(up, file) {
document.getElementById(file.id).getElementsByTagName('b')[0].innerHTML = '<span>' + file.percent + "%</span>";
},
Error: function(up, err) {
document.getElementById('console').appendChild(document.createTextNode("nError #" + err.code + ": " + err.message));
}
}
});
uploader.init();
</script>
</body>
</html>
<!-- end snippet -->
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。
如果需要上传多个文件，请告诉我。使用 plupload，我们可以上传任意数量的任意大小的文件。此示例适用于非常大的单个文件上传。不要忘记包括plupload.full.min.js。希望这有助于*强调文本**
下面是使用块上传文件的本机 Java 代码示例：
final String LF = "rn"; // 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，它定义了应使用分块流式处理。
您可以自己分解文件，使用 Socket API 发送文件，然后重新组装文件。
尝试上传 Apache Commons。 它支持流媒体，可能适合您。
使用 RandomAccessFile。我相信这已经在SO上涵盖了。
具有倒带（）/重置（）功能的Java文件输入
基本上，你只是寻找起点，从那里写多少字节，并记住你停止写的点。