downloadaction.java

类似于csdn的上传下载系统

/*
 * Generated by MyEclipse Struts
 * Template path: templates/java/JavaClass.vtl
 */
package org.adam.struts.action;

import java.io.UnsupportedEncodingException;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import org.adam.bean.Download;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.sql.DataSource;

import org.adam.bean.DB;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

/** 
 * MyEclipse Struts
 * Creation date: 08-11-2008
 * 
 * XDoclet definition:
 * @struts.action validate="true"
 */
public class DownloadAction extends Action {
	/*
	 * Generated Methods
	 */

	/** 
	 * Method execute
	 * @param mapping
	 * @param form
	 * @param request
	 * @param response
	 * @return ActionForward
	 */
	String filename;
	String path;
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) throws Exception{
		// TODO Auto-generated method stub
		request.setCharacterEncoding("GB2312");
		int download_id=Integer.parseInt(request.getParameter("id"));
		//System.out.println(download_id);
		ServletContext context=servlet.getServletContext();
		DataSource ds=(DataSource)context.getAttribute("download");
		DB db=new DB(ds);
		
		HttpSession session=request.getSession();
		//filename=request.getParameter("filename");
		
		filename=Download.getDownName(db, download_id);
		//System.out.println(filename);
		path = servlet.getServletContext().getRealPath("/fileupload")+"/"+filename;
		//System.out.println(path);
		downfile(response);
		return null;
	}
	public void downfile(HttpServletResponse response) throws IOException{
		String f;
		if(filename!=null)
		{
			File file=new File(path);
			
			if(!file.exists()) throw new IOException("文件不存在:"+file.getPath());
			else{
				f=toUTF8String(filename);
				
				response.setContentType("application/x-msdownload");
				response.setContentLength((int)file.length());
				response.setHeader("Content-Disposition", "attachment;filename="+f);
				write(response.getOutputStream());
			}
		}
	}
	public static String toUTF8String(String s){
		StringBuffer sb=new StringBuffer();
		for(int i=0;i<s.length();i++){
			char c=s.charAt(i);
			if(c>=0&&c<=255){
				sb.append(c);
			}
			else{
				byte[] b;
				try{
					b=Character.toString(c).getBytes("UTF-8");
				}catch(Exception e){System.out.println(e);b=new byte[0];}
				for(int j=0;j<b.length;j++){
					int k=b[j];
					if(k<0)
						k+=256;
					sb.append("%"+Integer.toHexString(k).toUpperCase());
				}
			}
		}
		return sb.toString();
	}
	
	protected void write(OutputStream os) throws IOException {
		FileInputStream fis = new FileInputStream(path);
		BufferedInputStream bis = new BufferedInputStream(fis);
		byte[] s = new byte[1024];
		int i = 0;
		while ((i = bis.read(s)) > 0) {
			os.write(s, 0, i);
		}
		if (os != null) {
			os.flush();
			os.close();
		}
		if (bis != null)
			bis.close();
		if (fis != null)
			fis.close();
	}
}