uploadaction.java

完整的STRUTS上传文件与下载文件的示例

/*
* $Header: /home/cvs/jakarta-struts/src/upload/org/apache/struts/webapp/upload/UploadAction.java,v 1.8 2003/02/28 02:18:23 dgraham Exp $
* $Revision: 1.8 $
* $Date: 2003/02/28 02:18:23 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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*    the documentation and/or other materials provided with the
*    distribution.
*
* 3. The end-user documentation included with the redistribution, if
*    any, must include the following acknowlegement:
*       "This product includes software developed by the
*        Apache Software Foundation (http://www.apache.org/)."
*    Alternately, this acknowlegement may appear in the software itself,
*    if and wherever such third-party acknowlegements normally appear.
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* 4. The names "The Jakarta Project", "Struts", and "Apache Software
*    Foundation" must not be used to endorse or promote products derived
*    from this software without prior written permission. For written
*    permission, please contact [e-mail].
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* 5. Products derived from this software may not be called "Apache"
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package org.apache.struts.webapp.upload;


import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

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

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.upload.FormFile;



/**
 * This class takes the UploadForm and retrieves the text value
 * and file attributes and puts them in the request for the display.jsp
 * page to display them
 *
 * @author Mike Schachter
 * @version $Revision: 1.8 $ $Date: 2003/02/28 02:18:23 $
 */


public class UploadAction extends Action
{
    public ActionForward execute(ActionMapping mapping,
                                 ActionForm form,
                                 HttpServletRequest request,
                                 HttpServletResponse response)
        throws Exception {

        if (form instanceof UploadForm) {

            //this line is here for when the input page is upload-utf8.jsp,
            //it sets the correct character encoding for the response
            String encoding = request.getCharacterEncoding();
            if ((encoding != null) && (encoding.equalsIgnoreCase("utf-8")))
            {
                response.setContentType("text/html; charset=utf-8");
            }

            UploadForm theForm = (UploadForm) form;

            //retrieve the text data
            String text = theForm.getTheText();

            //retrieve the query string value
            String queryValue = theForm.getQueryParam();

            //retrieve the file representation
            FormFile file = theForm.getTheFile();

            //retrieve the file name
            String fileName= file.getFileName();

            //retrieve the content type
            String contentType = file.getContentType();

            boolean writeFile = theForm.getWriteFile();

            //retrieve the file size
            String size = (file.getFileSize() + " bytes");

            String data = null;

            try {
                //retrieve the file data
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                InputStream stream = file.getInputStream();
                if (!writeFile) {
                    //only write files out that are less than 1MB
                    if (file.getFileSize() < (4*1024000)) {

                        byte[] buffer = new byte[8192];
                        int bytesRead = 0;
                        while ((bytesRead = stream.read(buffer, 0, 8192)) != -1) {
                            baos.write(buffer, 0, bytesRead);
                        }
                        data = new String(baos.toByteArray());
                    }
                    else {
                        data = new String("The file is greater than 4MB, " +
                                " and has not been written to stream." +
                                " File Size: " + file.getFileSize() + " bytes. This is a" +
                                " limitation of this particular web application, hard-coded" +
                                " in org.apache.struts.webapp.upload.UploadAction");
                    }
                }
                else {
                    //write the file to the file specified
                    OutputStream bos = new FileOutputStream(theForm.getFilePath());
                    int bytesRead = 0;
                    byte[] buffer = new byte[8192];
                    while ((bytesRead = stream.read(buffer, 0, 8192)) != -1) {
                        bos.write(buffer, 0, bytesRead);
                    }
                    bos.close();
                    data = "The file has been written to \"" + theForm.getFilePath() + "\"";
                }
                //close the stream
                stream.close();
            }
            catch (FileNotFoundException fnfe) {
                return null;
            }
            catch (IOException ioe) {
                return null;
            }

            //place the data into the request for retrieval from display.jsp
            request.setAttribute("text", text);
            request.setAttribute("queryValue", queryValue);
            request.setAttribute("fileName", fileName);
            request.setAttribute("contentType", contentType);
            request.setAttribute("size", size);
            request.setAttribute("data", data);

            //destroy the temporary file created
            file.destroy();

            //return a forward to display.jsp
            return mapping.findForward("display");
        }

        //this shouldn't happen in this example
        return null;
    }
}