将上传的文件保存在特定位置 [英] Saving uploaded file in specific location

问题描述

我有以下代码来处理服务器上的文件上传.但是如何将文件保存到服务器上的特定位置

I have the following code which handles files upload on the server. But how to save the file to a specific location on the server

import gwtupload.server.UploadAction;
import gwtupload.server.exceptions.UploadActionException;

import org.apache.commons.fileupload.FileItem;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Hashtable;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;




/**
 * This is an example of how to use UploadAction class.
 *  
 * This servlet saves all received files in a temporary folder, 
 * and deletes them when the user sends a remove request.
 * 
 * @author Manolo Carrasco Moñino
 *
 */
public class SampleUploadServlet extends UploadAction {

  private static final long serialVersionUID = 1L;

  Hashtable<String, String> receivedContentTypes = new Hashtable<String, String>();
  /**
   * Maintain a list with received files and their content types. 
   */
  Hashtable<String, File> receivedFiles = new Hashtable<String, File>();

  /**
   * Override executeAction to save the received files in a custom place
   * and delete this items from session.  
   */
  @Override
  public String executeAction(HttpServletRequest request, List<FileItem> sessionFiles) throws UploadActionException {
    String response = "";
    int cont = 0;
    for (FileItem item : sessionFiles) {
      if (false == item.isFormField()) {
        cont++;
        try {
          /// Create a new file based on the remote file name in the client
          // String saveName = item.getName().replaceAll("[\\/><\|\s"'{}()\[\]]+", "_");
          // File file =new File("/tmp/" + saveName);

          /// Create a temporary file placed in /tmp (only works in unix)
          // File file = File.createTempFile("upload-", ".bin", new File("/tmp"));

          /// Create a temporary file placed in the default system temp folder
          File file = File.createTempFile("upload-", ".bin");
          item.write(file);

          /// Save a list with the received files
          receivedFiles.put(item.getFieldName(), file);
          receivedContentTypes.put(item.getFieldName(), item.getContentType());

          /// Compose a xml message with the full file information
          response += "<file-" + cont + "-field>" + item.getFieldName() + "</file-" + cont + "-field>
";
          response += "<file-" + cont + "-name>" + item.getName() + "</file-" + cont + "-name>
";
          response += "<file-" + cont + "-size>" + item.getSize() + "</file-" + cont + "-size>
";
          response += "<file-" + cont + "-type>" + item.getContentType() + "</file-" + cont + "type>
";
        } 
        catch (Exception e) 
        {
        }
      }
    }

    /// Remove files from session because we have a copy of them
    removeSessionFileItems(request);

    /// Send information of the received files to the client.
    return "<response>
" + response + "</response>
";
  }

  /**
   * Get the content of an uploaded file.
   */
  @Override
  public void getUploadedFile(HttpServletRequest request, HttpServletResponse response) throws IOException {
    String fieldName = request.getParameter(PARAM_SHOW);
    File f = receivedFiles.get(fieldName);
    if (f != null) {
      response.setContentType(receivedContentTypes.get(fieldName));
      FileInputStream is = new FileInputStream(f);
      copyFromInputStreamToOutputStream(is, response.getOutputStream());
    } else {
      renderXmlResponse(request, response, ERROR_ITEM_NOT_FOUND);
   }
  }

  /**
   * Remove a file when the user sends a delete request.
   */
  @Override
  public void removeItem(HttpServletRequest request, String fieldName)  throws UploadActionException {
    File file = receivedFiles.get(fieldName);
    receivedFiles.remove(fieldName);
    receivedContentTypes.remove(fieldName);
    if (file != null) {
      file.delete();
    }
  }

}

推荐答案

你应该使用 File#createTempFile() 取一个目录.

You should use File#createTempFile() which takes a directory instead.

File file = File.createTempFile("upload-", ".bin", new File("/path/to/your/uploads"));
item.write(file);

或者如果您确实想将临时文件移动到另一个位置之后，请使用 File#renameTo().

Or if you actually want to move the temp file to another location afterwards, use File#renameTo().

File destination = new File("/path/to/your/uploads", file.getName());
file.renameTo(destination);

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