这个答案https://stackoverflow.com/a/33149413/6481542让我完成了将大文件上传到开发 Django 服务器的 90%，但我必须使用setFixedLengthStreamingMode才能使其正常工作。这需要在写入内容之前设置 Content-Length，因此需要对上述答案进行相当大的重写。这是我的最终结果
public class MultipartLargeUtility {
private final String boundary;
private static final String LINE_FEED = "\r\n";
private HttpURLConnection httpConn;
private String charset;
private OutputStream outputStream;
private PrintWriter writer;
private final int maxBufferSize = 4096;
private long contentLength = 0;
private URL url;
private List<FormField> fields;
private List<FilePart> files;
private class FormField {
public String name;
public String value;
public FormField(String name, String value) {
this.name = name;
this.value = value;
}
}
private class FilePart {
public String fieldName;
public File uploadFile;
public FilePart(String fieldName, File uploadFile) {
this.fieldName = fieldName;
this.uploadFile = uploadFile;
}
}
/**
* This constructor initializes a new HTTP POST request with content type
* is set to multipart/form-data
*
* @param requestURL
* @param charset
* @throws IOException
*/
public MultipartLargeUtility(String requestURL, String charset, boolean requireCSRF)
throws IOException {
this.charset = charset;
// creates a unique boundary based on time stamp
boundary = "===" + System.currentTimeMillis() + "===";
url = new URL(requestURL);
fields = new ArrayList<>();
files = new ArrayList<>();
if (requireCSRF) {
getCSRF();
}
}
/**
* Adds a form field to the request
*
* @param name field name
* @param value field value
*/
public void addFormField(String name, String value)
throws UnsupportedEncodingException {
String fieldContent = "--" + boundary + LINE_FEED;
fieldContent += "Content-Disposition: form-data; name=\"" + name + "\"" + LINE_FEED;
fieldContent += "Content-Type: text/plain; charset=" + charset + LINE_FEED;
fieldContent += LINE_FEED;
fieldContent += value + LINE_FEED;
contentLength += fieldContent.getBytes(charset).length;
fields.add(new FormField(name, value));
}
/**
* Adds a upload file section to the request
*
* @param fieldName name attribute in <input type="file" name="..." />
* @param uploadFile a File to be uploaded
* @throws IOException
*/
public void addFilePart(String fieldName, File uploadFile)
throws IOException {
String fileName = uploadFile.getName();
String fieldContent = "--" + boundary + LINE_FEED;
fieldContent += "Content-Disposition: form-data; name=\"" + fieldName
+ "\"; filename=\"" + fileName + "\"" + LINE_FEED;
fieldContent += "Content-Type: "
+ URLConnection.guessContentTypeFromName(fileName) + LINE_FEED;
fieldContent += "Content-Transfer-Encoding: binary" + LINE_FEED;
fieldContent += LINE_FEED;
// file content would go here
fieldContent += LINE_FEED;
contentLength += fieldContent.getBytes(charset).length;
contentLength += uploadFile.length();
files.add(new FilePart(fieldName, uploadFile));
}
/**
* Adds a header field to the request.
*
* @param name - name of the header field
* @param value - value of the header field
*/
//public void addHeaderField(String name, String value) {
// writer.append(name + ": " + value).append(LINE_FEED);
// writer.flush();
//}
/**
* Completes the request and receives response from the server.
*
* @return a list of Strings as response in case the server returned
* status OK, otherwise an exception is thrown.
* @throws IOException
*/
public List<String> finish() throws IOException {
List<String> response = new ArrayList<String>();
String content = "--" + boundary + "--" + LINE_FEED;
contentLength += content.getBytes(charset).length;
if (!openConnection()) {
return response;
}
writeContent();
// checks server's status code first
int status = httpConn.getResponseCode();
if (status == HttpURLConnection.HTTP_OK) {
BufferedReader reader = new BufferedReader(new InputStreamReader(
httpConn.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
response.add(line);
}
reader.close();
httpConn.disconnect();
} else {
throw new IOException("Server returned non-OK status: " + status);
}
return response;
}
private boolean getCSRF()
throws IOException {
/// First, need to get CSRF token from server
/// Use GET request to get the token
CookieManager cookieManager = new CookieManager();
CookieHandler.setDefault(cookieManager);
HttpURLConnection conn = null;
conn = (HttpURLConnection) url.openConnection();
conn.setUseCaches(false); // Don't use a Cached Copy
conn.setRequestMethod("GET");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.getContent();
conn.disconnect();
/// parse the returned object for the CSRF token
CookieStore cookieJar = cookieManager.getCookieStore();
List<HttpCookie> cookies = cookieJar.getCookies();
String csrf = null;
for (HttpCookie cookie : cookies) {
Log.d("cookie", "" + cookie);
if (cookie.getName().equals("csrftoken")) {
csrf = cookie.getValue();
break;
}
}
if (csrf == null) {
Log.d(TAG, "Unable to get CSRF");
return false;
}
Log.d(TAG, "Received cookie: " + csrf);
addFormField("csrfmiddlewaretoken", csrf);
return true;
}
private boolean openConnection()
throws IOException {
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setDoOutput(true); // indicates POST method
httpConn.setDoInput(true);
//httpConn.setRequestProperty("Accept-Encoding", "identity");
httpConn.setFixedLengthStreamingMode(contentLength);
httpConn.setRequestProperty("Connection", "Keep-Alive");
httpConn.setRequestProperty("Content-Type",
"multipart/form-data; boundary=" + boundary);
outputStream = new BufferedOutputStream(httpConn.getOutputStream());
writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
true);
return true;
}
private void writeContent()
throws IOException {
for (FormField field : fields) {
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + field.name + "\"")
.append(LINE_FEED);
writer.append("Content-Type: text/plain; charset=" + charset).append(
LINE_FEED);
writer.append(LINE_FEED);
writer.append(field.value).append(LINE_FEED);
writer.flush();
}
for (FilePart filePart : files) {
String fileName = filePart.uploadFile.getName();
writer.append("--" + boundary).append(LINE_FEED);
writer.append(
"Content-Disposition: form-data; name=\"" + filePart.fieldName
+ "\"; filename=\"" + fileName + "\"")
.append(LINE_FEED);
writer.append(
"Content-Type: "
+ URLConnection.guessContentTypeFromName(fileName))
.append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
writer.append(LINE_FEED);
writer.flush();
FileInputStream inputStream = new FileInputStream(filePart.uploadFile);
int bufferSize = Math.min(inputStream.available(), maxBufferSize);
byte[] buffer = new byte[bufferSize];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer, 0, bufferSize)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.flush();
inputStream.close();
writer.append(LINE_FEED);
writer.flush();
}
writer.append("--" + boundary + "--").append(LINE_FEED);
writer.close();
}
}
用法与上面的答案基本相同，但我已经包含了 Django 默认使用的 CSRF 支持和表单
boolean useCSRF = true;
MultipartLargeUtility multipart = new MultipartLargeUtility(url, "UTF-8",useCSRF);
multipart.addFormField("param1","value");
multipart.addFilePart("filefield",new File("/path/to/file"));
List<String> response = multipart.finish();
Log.w(TAG,"SERVER REPLIED:");
for(String line : response) {
Log.w(TAG, "Upload Files Response:::" + line);
}