【发布时间】：2016-05-05 20:54:44
【问题描述】：
我在GWT中开发了一个小应用程序，在进行一些操作后上传和下载文件，它工作正常，但是文件下载后加载对话框图像永远不会停止，请指教。
客户端代码
public class Firstmodule implements EntryPoint
{
public void onModuleLoad()
{
final PopupPanel popup = new PopupPanel(false, true); // Create a modal dialog box that will not auto-hide
final FileUpload fileUpload = new FileUpload();
final FormPanel form = new FormPanel();
VerticalPanel vPanel = new VerticalPanel();
Image img = new Image("download.png");
vPanel.add(img);
form.setMethod(FormPanel.METHOD_POST);
// The HTTP request is encoded in multipart format.
form.setEncoding(FormPanel.ENCODING_MULTIPART);
form.setTitle("Family_Common_Fet");
form.setAction(GWT.getHostPageBaseURL() + "FileUploadGreeting");
form.setWidget(vPanel);
fileUpload.setName("uploader");
vPanel.add(fileUpload);
vPanel.setSpacing(20);
Label maxUpload = new Label();
maxUpload.setText("Text input file header: Datasheet, Vendor Code");
vPanel.add(maxUpload);
final Button submit = new Button("Upload and Run");
vPanel.add(submit);
submit.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event)
{
String filename = fileUpload.getFilename();
if(!filename.endsWith(".txt"))
{
System.out.println(filename);
Window.alert("only *.txt files accepted");
return;
}
else if(filename.length() == 0)
{
Window.alert("Please Select Text File");
return;
}
else
{
// loading dialog image
popup.add(new Image("loading_animation1.gif"));
popup.setGlassEnabled(true); // Enable the glass panel
popup.center(); // Center the popup and make it visible
submit.setEnabled(false);
submit.setFocus(true);
form.submit();
}
}
});
// Add an event handler to the form.
form.addSubmitHandler(new FormPanel.SubmitHandler() {
public void onSubmit(SubmitEvent event)
{
// This event is fired just before the form is submitted. We can take
// this opportunity to perform validation.
}
});
form.addSubmitCompleteHandler(new FormPanel.SubmitCompleteHandler() {
public void onSubmitComplete(SubmitCompleteEvent event)
{
//trying to stop the loading dialodg
popup.setGlassEnabled(false);
submit.setEnabled(true);
form.reset();
}
});
DecoratorPanel decPanel = new DecoratorPanel();
decPanel.setWidget(form);
RootPanel.get("uploadContainer").add(decPanel);
}
servlet 代码
public class UploadFileHandler extends HttpServlet
{
private static final long serialVersionUID = 1L;
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
System.out.println("Inside doPost");
// Create a factory for disk-based file items
FileItemFactory factory = new DiskFileItemFactory();
// Create a new file upload handler
ServletFileUpload fileUpload = new ServletFileUpload(factory);
// sizeMax - The maximum allowed size, in bytes. The default value of -1 indicates, that there is no limit.
// 1048576 bytes = 1024 Kilobytes = 1 x 10 Megabyte
fileUpload.setSizeMax(10485760);
System.out.println(request.getRemoteAddr());
if(!ServletFileUpload.isMultipartContent(request))
{
try
{
throw new FileUploadException("error multipart request not found");
}catch(FileUploadException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
try
{
List<FileItem> items = fileUpload.parseRequest(request);
if(items == null)
{
response.getWriter().write("File not correctly uploaded");
return;
}
Iterator<FileItem> iter = items.iterator();
String absofilepath = null;
String fileName = null;
String filepath = "temp//fileOutput_" + System.currentTimeMillis() + ".txt";
while(iter.hasNext())
{
FileItem item = (FileItem) iter.next();
////////////////////////////////////////////////
// http://commons.apache.org/fileupload/using.html
////////////////////////////////////////////////
// if (item.isFormField()) {
fileName = item.getName();
System.out.println("fileName is : " + fileName);
String typeMime = item.getContentType();
System.out.println("typeMime is : " + typeMime);
int sizeInBytes = (int) item.getSize();
System.out.println("Size in bytes is : " + sizeInBytes);
// byte[] file = item.get();
absofilepath = getServletContext().getRealPath(filepath);
item.write(new File(absofilepath));
// }
}
String request_ip = getClientIpAddr(request);
System.out.println("Request IP:" + request_ip);
String tempoutFile = "output//" + fileName + System.currentTimeMillis() + ".txt";
String absooutFile = getServletContext().getRealPath(tempoutFile);
System.out.println("ouput file : " + absooutFile);
//************ some other operations in code*******///
}catch(Exception e){
e.printStackTrace();
PrintWriter out = response.getWriter();
response.setHeader("Content-Type", "text/html");
out.println("an Error has occuredin Exporter.bat" + e);
out.flush();
out.close();
}
// ****************************Downlaod **********************************//
downloadFile(request, response, absooutFile);
/*when i sing hashed code below it's return error in console and didn't stop the loading dialog image */
// PrintWriter out = response.getWriter();
// response.setHeader("Content-Type", "text/html");
// out.println("Check output File");
// System.out.println("Upload Ok");
// out.flush();
// out.close();
}catch(SizeLimitExceededException e)
{
System.out.println("File size exceeds the limit : 10 MB!!");
PrintWriter out = response.getWriter();
response.setHeader("Content-Type", "text/html");
out.println("Maximum file size should not exceed 10MB!!");
out.flush();
out.close();
}catch(Exception e)
{
e.printStackTrace();
PrintWriter out = response.getWriter();
response.setHeader("Content-Type", "text/html");
out.println("an Error has occured");
out.flush();
out.close();
}
}
public static String getClientIpAddr(HttpServletRequest request)
{
String ip = request.getHeader("X-Forwarded-For");
if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip))
{
ip = request.getHeader("Proxy-Client-IP");
}
if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip))
{
ip = request.getHeader("WL-Proxy-Client-IP");
}
if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip))
{
ip = request.getHeader("HTTP_CLIENT_IP");
}
if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip))
{
ip = request.getHeader("HTTP_X_FORWARDED_FOR");
}
if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip))
{
ip = request.getRemoteAddr();
}
return ip;
}
private void downloadFile(HttpServletRequest req, HttpServletResponse resp, String filePath)
{
try
{
File f = new File(filePath);
int length = 0;
ServletOutputStream op = resp.getOutputStream();
ServletContext context = getServletConfig().getServletContext();
String mimetype = context.getMimeType(filePath);
resp.setContentType((mimetype != null) ? mimetype : "application/octet-stream");
resp.setContentLength((int) f.length());
resp.setHeader("Content-Disposition", "attachment; filename=Fam_Com_Fet.txt");
DataInputStream in = new DataInputStream(new FileInputStream(f));
byte[] bbuf = new byte[in.available()];
while((in != null) && ((length = in.read(bbuf)) != -1))
{
op.write(bbuf, 0, length);
}
in.close();
op.flush();
op.close();
// f.delete();
}catch(IOException ioe)
{
ioe.printStackTrace();
}
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
doPost(request, response);
}
谢谢
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标签： java servlets gwt download