downloadservlet.java

一个JAVA的小例子 大家不放运行一下 熟悉一下

package com.abc.dl.servlets;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DownloadServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		String aValue = (String)getServletContext().getAttribute("value");
		System.out.println(aValue); //这段代码没有任何逻辑用途，仅用于检测context中共享数据的设置
		
		String op = request.getParameter("fileid");
		
		if(op==null){
			op = "";
		}
		if(op.equals("1")) {
			response.setContentType("application/x-download");
			op = "file1.zip";
			
		}else if (op.equals("2")) {
			response.setContentType("application/x-download");
			op = "file2.zip";
		}
		else {
			request.getRequestDispatcher("/servlet/main.html").forward(request, response);
			return;			
		}
		
		response.setHeader("Content-Disposition", "attachment;filename=\"" + op + "\"" );
		op = getServletContext().getRealPath("/WEB-INF/software/" + op);
        //System.out.println(op);
		
		OutputStream os = response.getOutputStream();
		
		FileInputStream fis = new FileInputStream( op  );
				
		BufferedInputStream bis = new BufferedInputStream(fis);
		BufferedOutputStream bos = new BufferedOutputStream(os);
		
		
		byte[] buff = new byte[4096];
		int r = 0;
		
		while( (r=bis.read(buff)) != -1) {
			bos.write(buff,0,r);			
		}
		
		bis.close(); fis.close();		
		
	}
}