完成： 使用apache fileupload jar使用applet和servlet将文件从本地上传到服务器。
试过： 我使用了一个简单的jsp，带有一个浏览按钮，并将操作发布到我的servlet（我使用apache fileupload）。我成功地将文件上传到服务器。
问题： 我正在尝试使用applet从本地计算机上传文件。我不想手动选择文件，而是上传特定文件夹中存在的文件。现在我已经硬编码了文件夹。我可以查看该文件夹并获取我要上传的文件列表。 此外，我已成功建立从applet到servlet的连接。
问题出现在servlet中的upload.parseRequest(request)。 我在想它，因为applet无法发布到servlet的请求对象。
另外，我已在我的applet中将请求类型设置为multipart/form-data。
现在，我试图将文件的绝对路径传递给servlet并上传。
我见过其他帖子，其中字节流数据从applet传递到servlet，但servlet使用传统的File.write。 对我来说，必须使用apache fileupload来实现这一点。
请建议如何将文件/文件路径从applet传递到servlet，其中上传由apache fileupload处理。
下面是我的FileUploadHandler（处理HTTP请求的地方）和FileUpload（这是我的applet）
以下是 FileUpload处理程序：
@WebServlet(name = "FileUploadHandler", urlPatterns = { "/upload" })
@MultipartConfig
public class FileUploadHandler extends HttpServlet {
String uploadFolder ="";
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
System.out.println("doPost-servlet URL is: "
+ request.getRequestURL());
try {
uploadFolder = fileToUpload(request);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
uploadFolder = getServletContext().getRealPath("")+ File.separator;
// Create a factory for disk-based file items
DiskFileItemFactory factory = new DiskFileItemFactory();
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// process only if its multipart content
if (ServletFileUpload.isMultipartContent(request)) {
System.out.println("Yes, it is a multipart request...");
try {
List<FileItem> multiparts = upload.parseRequest(request);
System.out.println("Upload.parseRequest success !");
for (FileItem item : multiparts) {
if (!item.isFormField()) {
String name = new File(item.getName()).getName();
item.write(new File(uploadFolder + File.separator
+ name));
}
}
System.out.println("File uploaded to server !");
// File uploaded successfully
request.setAttribute("message", "File Uploaded Successfully");
} catch (Exception ex) {
request.setAttribute("message", "File Upload Failed due to "
+ ex);
}
} if(!ServletFileUpload.isMultipartContent(request)){
throw new ServletException("Content type is not multipart/form-data");
}
doGet(request, response);
//request.getRequestDispatcher("/result.jsp").forward(request, response);
OutputStream outputStream = response.getOutputStream();
ObjectOutputStream objectOutputStream = new ObjectOutputStream(outputStream);
objectOutputStream.writeObject("Success !");
objectOutputStream.flush();
objectOutputStream.close();
}
private String fileToUpload(HttpServletRequest request) throws IOException,
ClassNotFoundException {
ServletInputStream servletIn = request.getInputStream();
ObjectInputStream in = new ObjectInputStream(servletIn);
String uploadFile = (String) in.readObject();
System.out.println("Value in uploadFolder is: " + uploadFile);
return uploadFile;
}
以下是文件上传小程序：
public class FileUpload extends Applet {
private JButton capture;
private JTextField textField;
private final String pathDirectory = "C:\\";
private final String captureConfirmMessage = "Are you sure you want to continue?";
private final String confirmDialogTitle = "Confirm upload";
final File folder = new File(pathDirectory);
public void init() {
upload= new JButton("Upload");
textField = new JTextField();
capture.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int selection = JOptionPane.showConfirmDialog(upload,
uploadConfirmMessage, confirmDialogTitle,
JOptionPane.YES_NO_OPTION);
if (selection == JOptionPane.OK_OPTION) {
listFilesForFolder(folder);
} else if (selection == JOptionPane.CANCEL_OPTION) {
JOptionPane.showMessageDialog(upload,
"You have aborted upload", "Upload Cancelled", 2);
}
}
});
add(upload);
add(textField);
}
public void listFilesForFolder(final File folder) {
for (final File fileEntry : folder.listFiles()) {
if (fileEntry.isDirectory()) {
listFilesForFolder(fileEntry);
} else {
try {
onSendData(fileEntry.getAbsolutePath());
System.out.println(fileEntry.getAbsolutePath());
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
private URLConnection getServletConnection() throws MalformedURLException,
IOException {
// Open the servlet connection
URL urlServlet = new URL("http://localhost:8081/UploadFile/upload");
HttpURLConnection servletConnection = (HttpURLConnection) urlServlet
.openConnection();
// Config
servletConnection.setDoInput(true);
servletConnection.setDoOutput(true);
servletConnection.setUseCaches(false);
servletConnection.setDefaultUseCaches(false);
servletConnection.setRequestProperty("Content-Type", "multipart/form-data;");
servletConnection.connect();
return servletConnection;
}
private void onSendData(String fileEntry) {
try {
// Send data to the servlet
HttpURLConnection servletConnection = (HttpURLConnection) getServletConnection();
OutputStream outstream = servletConnection.getOutputStream();
ObjectOutputStream objectOutputStream= new ObjectOutputStream(
outstream);
objectOutputStream.writeObject(fileEntry);
// Receive result from servlet
InputStream inputStream = servletconnection.getInputStream();
ObjectInputStream objectInputStream = new ObjectInputStream(
inputStream);
String result = (String) objectInputStream.readObject();
objectInputStream.close();
inputStream.close();
out.flush();
out.close();
// Display result on the applet
textField.setText(result);
} catch (java.net.MalformedURLException mue) {
mue.printStackTrace();
textField.setText("Invalid serlvetUrl, error: " + mue.getMessage());
} catch (java.io.IOException ioe) {
ioe.printStackTrace();
textField.setText("Couldn't open a URLConnection, error: "
+ ioe.getMessage());
} catch (Exception e) {
e.printStackTrace();
textField.setText("Exception caught, error: " + e.getMessage());
}
}
public void paint(Graphics g) {
g.drawString("Click the button above to capture", 5, 50);
}
答案 0 :(得分：0)
我终于可以成功地将请求从applet发布到servlet了。 我错过了一个简单的逻辑。我没有添加标题和预告片，同时发送到servlet，这是密钥，在servlet中将传入的请求标识为多部分数据。
FileInputStream fileInputStream = new FileInputStream(new File(
fileEntry));
dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
dataOutputStream
.writeBytes("Content-Disposition: form-data; name=\"upload\";"
+ " filename=\"" + fileEntry + "\"" + lineEnd);
dataOutputStream.writeBytes(lineEnd);
// create a buffer of maximum size
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dataOutputStream.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
System.out.println(fileEntry + " uploaded.");
}
// send multipart form data necesssary after file data
dataOutputStream.writeBytes(lineEnd);
dataOutputStream.writeBytes(twoHyphens + boundary + twoHyphens
+ lineEnd);
我添加了标题和预告片，并使用它来创建URL连接。
private URLConnection getServletConnection() throws MalformedURLException,
IOException {
// Open the servlet connection
URL urlServlet = new URL("http://localhost:8083/UploadFile/upload");
HttpURLConnection servletConnection = (HttpURLConnection) urlServlet
.openConnection();
// Config
servletConnection.setDoInput(true);
servletConnection.setDoOutput(true);
servletConnection.setUseCaches(false);
servletConnection.setDefaultUseCaches(false);
servletConnection.setRequestMethod("POST");
servletConnection.setRequestProperty("Content-Type",
"multipart/form-data;boundary=" + this.boundary);
servletConnection.setRequestProperty("Connection", "Keep-Alive");
servletConnection.connect();
return servletConnection;
}
然后，在servlet中，我只是使用upload.ParseRequest（request）读取数据。 谢谢你的帮助。