I'm trying to use HttpClient's PutMethod to transfer a file from my client application
to the associated Servlet. There isn't actually a UI for this application, in the end
I want to automate the process. I'm not sure if there is a better way of doing a file
upload such as this, but what I've been trying to do uses a couple of requests to the
Servlet to implement the entire file transfer:
1. First, the client uses a POST method to send the file name (contained in a
parameter) to be transferred to the servlet.
2. The servlet then takes the file name and sets an attribute on the HttpSession
object associated with the client to be the name of the transferring file.
3. The client then uses a PUT method (via HttpClient's PutMethod object) to transfer
the file contents.
4. The servlet reads the contents into a byte array, and extracts the file name from
the associated session object.
5. Finally the servlet creates a file with the extracted name, opens a
FileOutputStream and writes the contents to the newly created file.
I've never actually seen something like this done, but it seemed logical enough...
right (these words always seem to mean trouble!)? So, does anyone know what it is
that I could be doing wrong? The file name comes through fine and the Servlet creates
the new file with the corresponding name without a problem. The file even ends up
with the appropriate size. The problem is that when I take a look at the newly
created file, it just holds spaces in place of the original text.
Thanks,
Daniel
I've tried to put together a digest version of what I'm trying to do...
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Client Class:
------------------------------------------------------------------------------------------------------------
public class FileUploadClient
{
public static void main(String args[])
{
try
{
java.net.URL serverUrl = new java.net.URL("http://localhost:8081/upload";);
File uploadFile = new File("C:\\Temp\\UploadFile.txt");
PostMethod post = new PostMethod();
post.setPath(serverUrl.getPath());
post.addParameter("file-name", uploadFile.getName());
HttpClient client = new HttpClient();
HostConfiguration hostConfig = new HostConfiguration();
hostConfig.setHost(serverUrl.getHost(), serverUrl.getPort(),
serverUrl.getProtocol());
client.setConnectionTimeout(30000);
client.setHostConfiguration(hostConfig);
client.executeMethod(post);
String fileToUpload = post.getResponseBodyAsString();
PutMethod put = new PutMethod();
put.setPath(serverUrl.getPath());
put.setRequestBody(uploadFile);
client.executeMethod(put);
}
catch(Exception ex)
{
ex.printStackTrace();
}
finally
{
System.out.println("Finished Transfer..");
}
}
}
------------------------------------------------------------------------------------------------------------
Servlet Class:
------------------------------------------------------------------------------------------------------------
public class FileUploadServlet extends HttpServlet
{
public void doPost(HttpServletRequest req, HttpServletResponse res) throws
IOException, ServletException
{
HttpSession session = req.getSession(true);
String fileName = req.getParameter("file-name");
session.setAttribute("file-name", fileName);
PrintWriter out = res.getWriter();
out.println(fileName);
out.flush();
out.close();
}
public void doPut(HttpServletRequest req, HttpServletResponse res) throws
IOException, ServletException
{
HttpSession session = req.getSession(false);
String fileName = (String)session.getAttribute("file-name");
File uploadedFile = new File(fileName);
uploadedFile.createNewFile();
ServletInputStream in = req.getInputStream();
byte[] reqContent;
int contentLength = 0;
while(in.read() != -1)
++contentLength;
reqContent = new byte[contentLength];
in.read(reqContent);
FileOutputStream fOut = new FileOutputStream(uploadedFile);
fOut.write(reqContent);
fOut.flush();
fOut.close();
}
}
