我从未在3天内开始研究Google应用引擎，最后遇到了这个我无法解决的问题。很多研究但是可以找到令人信服的东西。中号
设置我的Google App Engine帐户后，当我调用我的应用程序网址“my-app-id.appspot.com/myservlet”时，GAE上的简单Servlet可以在我的Google存储桶中写入.txt文件。相同的代码片段在这里：
fetchurl.java
DefaultHttpClient hc=new DefaultHttpClient();
ResponseHandler <String> res=new BasicResponseHandler();
HttpGet postMethod=new HttpGet("http://my-app-id.appspot.com/uploadservlet");
String response=hc.execute(postMethod,res);
uploadservlet.java
An example @ Complete Sample App at this link:
https://developers.google.com/appengine/docs/java/googlestorage/overview
现在我的问题是当我使用多部分通过POST方法发送一些文件时，Servlet @ app引擎无法工作，我在eclipse中收到错误消息“Filenotfound”。
Android端的.java文件
urlString = "http://my-app-id.appspot.com/uploadservlet";
URL url = new URL(urlString);
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(90000);
// Allow Inputs
conn.setDoInput(true);
// Allow Outputs
conn.setDoOutput(true);
// Don't use a cached copy.
conn.setUseCaches(false);
// Use a post method.
conn.setRequestMethod("POST");
isOK = true;
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type",
"multipart/form-data;boundary=" + boundary);
DataOutputStream dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=param1;filename="
+ param1 + "" + lineEnd);
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + lineEnd);
Log.e(Tag, "Param1 are written");
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=param2;filename="
+ param2 + "" + lineEnd);
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + lineEnd);
Log.e(Tag, "Param2 are written");
FileInputStream fileInputStream = new FileInputStream(new File(
path));
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=uploadedfile;filename="
+ path + "" + lineEnd);
dos.writeBytes(lineEnd);
Log.e(Tag, "Headers are written");
// create a buffer of maximum size
int bytesAvailable = fileInputStream.available();
int maxBufferSize = 1000;
// int bufferSize = Math.min(bytesAvailable, maxBufferSize);
byte[] buffer = new byte[bytesAvailable];
// read file and write it into form...
int bytesRead = fileInputStream.read(buffer, 0, bytesAvailable);
while (bytesRead > 0)
{
dos.write(buffer, 0, bytesAvailable);
bytesAvailable = fileInputStream.available();
bytesAvailable = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bytesAvailable);
}
// send multipart form data necesssary after file data...
//dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
我想知道这种方法是否正确。如果不是什么是另一种解决方案..我也看了blobstorage但它也是一样的，写文件到桶而不上传..请帮助我们......任何事都会很棒并且赞赏!!!
Servlet code to handle file upload and save to Google storage--
@MultipartConfig
@SuppressWarnings("serial")
public class SecondtrygoogleServlet extends HttpServlet
{
public static String BUCKETNAME = "androidbucket";
public static String FILENAME = "shikhatry.txt";
private static final long serialVersionUID = 1L;
private static final int THRESHOLD_SIZE = 1024 * 1024 * 3; // 3MB
private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
private static final int REQUEST_SIZE = 1024 * 1024 * 50; // 50MB
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
// checks if the request actually contains upload file
if (!ServletFileUpload.isMultipartContent(request)) {
// if not, we stop here
return;
}
response.setContentType("text/plain");
response.getWriter().println("Hello, test1 world");
// configures some settings
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(THRESHOLD_SIZE);
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setFileSizeMax(MAX_FILE_SIZE);
upload.setSizeMax(REQUEST_SIZE);
java.io.PrintWriter out = response.getWriter( );
try {
// parses the request's content to extract file data
List<?> formItems = upload.parseRequest(request);
out.println("Number of fields: " + formItems.size());
Iterator<?> iter = formItems.iterator();
// iterates over form's fields
while (iter.hasNext())
{
out.println("Inside while loop");
FileItem item = (FileItem) iter.next();
// processes only fields that are not form fields
if (!item.isFormField())
{
String temp = item.getFieldName();
out.println("Parameter Name"+temp);
if(temp.equals("uploadedfile"))
{
String fileName = new File(item.getName()).getName();
FILENAME = fileName+".txt";
out.println("Filename"+fileName);
FileService fileService = FileServiceFactory.getFileService();
GSFileOptionsBuilder optionsBuilder = new GSFileOptionsBuilder()
.setBucket(BUCKETNAME)
.setKey(FILENAME)
.setMimeType("text/html") //audio/mp3 text/html
.setAcl("public_read")
.addUserMetadata("myfield1", "my field value");
AppEngineFile writableFile =
fileService.createNewGSFile(optionsBuilder.build());
// Open a channel to write to it
boolean lock = false;
FileWriteChannel writeChannel =
fileService.openWriteChannel(writableFile, lock);
// Different standard Java ways of writing to the channel
// are possible. Here we use a PrintWriter:
InputStream inputStream = item.getInputStream();
int readBytes = 0;
byte[] buffer = new byte[10000];
while ((readBytes = inputStream.read(buffer, 0, 10000)) != -1)
{
writeChannel.write(ByteBuffer.wrap(buffer));
}
inputStream.close();
writeChannel.closeFinally();
response.getWriter().println("Done writing...");
}
else if(temp.equals("param1"))
{
out.println("Inside param1");
//String param1Val = new File(item.getName()).getName();
//BUCKETNAME = param1Val;
}
else if(temp.equals("param2"))
{
out.println("Inside param2");
//String param2Val = new File(item.getName()).getName();
//BUCKETNAME = param2Val;
}
}
}
request.setAttribute("message", "Upload has been done successfully!");
} catch (Exception ex) {
request.setAttribute("message", "There was an error: " + ex.getMessage());
}
}
答案 0 :(得分：1)
选项包括：
一个。使用createUploadURL和表单上传大文件，或
湾使用您的方法然后解码解析上传并在servlet中自己写入blobstore（文件需要小于32MB），或者
℃。使用Google Cloud Storage API直接写入GCS，然后将上传的文件名发布到您的应用程序。