javaweb下载文件模板

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet implementation class DownloadServlet
*/
public class DownloadServlet extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取需要下载文件名称
String filename = request.getParameter("filename");
//获取下载的类型
response.setContentType(this.getServletContext().getMimeType(filename));
//告知客户端需要下载
response.setHeader("Content-Disposition", "attachment;filename="+filename);
//获取文件的绝对路径
String path = this.getServletContext().getRealPath("download/"+filename);
//获取文件的输入源
InputStream in = new FileInputStream(path);
//获取输出流
ServletOutputStream out = response.getOutputStream();
int len=0;
byte[] buffer = new byte[1024];
while((len=in.read(buffer))>0) {
out.write(buffer,0,len);
}
in.close();
out.close();
}


protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}

}