downfileaction.java

一个不错的bbs论坛系统．对初学者很有帮助

package com.yhbbs.upload.action;

import java.io.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.DownloadAction;

import com.yhbbs.utils.ReqUtils;

/**
 * <p> * Title:下载文件列表Action</p>
 * <li>下载文件列表模块</li><br>
 * <b>CopyRight: yyhweb[由由华网]</b>
 * @author stephen
 * @version YH-2.0
 */
public class DownFileAction extends DownloadAction {
	protected class ByteArrayStreamInfo implements StreamInfo {

		protected String contentType;

		protected byte bytes[];

		public String getContentType() {
			return contentType;
		}

		public InputStream getInputStream() throws IOException {
			return new ByteArrayInputStream(bytes);
		}

		public ByteArrayStreamInfo(String contentType, byte bytes[]) {
			this.contentType = contentType;
			this.bytes = bytes;
		}

		public ByteArrayStreamInfo(String contentType, String str) {
			this.contentType = contentType;
			bytes = str.getBytes();
		}
	}

	protected StreamInfo getStreamInfo(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		String contentType = "application/octet-stream";
		String fileNamePath;

		int artId = ReqUtils.getInt(request, "artId");
		String fileName;
		if (artId > 0)
			fileName = null;
		else
			fileName = ReqUtils.getString(request, "fileName");
		if (fileName == null)
			fileName = "yhbbs.txt";
		fileNamePath = request.getRealPath("") + "/webapp/upload/" + fileName;
		int splashIndex = fileName.lastIndexOf("/");
		String saveName = splashIndex <= 0 ? fileName : fileName.substring(splashIndex + 1);
		response.setHeader("Content-disposition", "attachment; filename="+ saveName);

		File file = new File(fileNamePath);
		if (!file.exists())
			return new ByteArrayStreamInfo(contentType,"I'am sorry,the file you request does not exist.");
		else
			return new FileStreamInfo(contentType, file);
	}
}