downloadservlet.java

WEB下载文件

import javax.servlet.*;
import javax.servlet.http.*;

import org.apache.log4j.Logger;

import java.io.*;
import java.net.URLEncoder;

public class DownloadServlet extends HttpServlet {
	private String contentType = "application/x-msdownload";

	private String enc = "utf-8";

	private String fileRoot = "";
	
    private Logger log = Logger.getLogger(MarkServlet.class.getName());	
	 
	public void init(ServletConfig config) throws ServletException {
		String tempStr = config.getInitParameter("contentType");
		if (tempStr != null && !tempStr.equals("")) {
			contentType = tempStr;
		}
		tempStr = config.getInitParameter("enc");
		if (tempStr != null && !tempStr.equals("")) {
			enc = tempStr;
		}
	}


	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {

		response.setContentType("text/html; charset=utf-8");
	 
		String filePath="";
		if((String)request.getParameter("filePath")!=null){
			filePath=(String)request.getParameter("filePath");
			log.debug("filePath :"+filePath);
		}else{
			 filePath=request.getSession().getServletContext().getRealPath("/export/");
			 log.debug("filePath :"+filePath);
		}
		String fileName =(String)request.getParameter("fileName");

		File file = new File(filePath,fileName);

		if (file.exists()) {
			String filename = URLEncoder.encode(fileName, enc);
			response.reset();
			response.setContentType(contentType);
			response.addHeader("Content-Disposition", "attachment; filename=\""
					+ filename + "\"");
			int fileLength = (int) file.length();
			response.setContentLength(fileLength);
			if (fileLength != 0) {
				InputStream inStream=null;
				ServletOutputStream servletOS=null;				
				try{					
					inStream = new FileInputStream(file);
					byte[] buf = new byte[4096];
					servletOS = response.getOutputStream();
					int readLength;
					while (((readLength = inStream.read(buf)) != -1)) {
						servletOS.write(buf, 0, readLength);
					}
				}catch(Exception e){
					log.error(e,e);
				}finally{
					try{
						inStream.close();
						servletOS.flush();
						servletOS.close();
					}catch(Exception e){
						log.error(e,e);						
					}
				}
			}
		}
	}
	
	
	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		doGet(request,response);
	}	

}