javaEE 文件下载(响应头Content-Disposition), 中文文件名下载, 判断不同浏览器(请求头User-Agent)

xxxServlet：

package com.xxx.content;

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

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

import sun.misc.BASE64Encoder;

public class DownloadServlet extends HttpServlet {

	protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
		
		//*******下载文件名是中文的文件*******

		String filename = request.getParameter("filename"); // ???.jpg (中文乱码)
		//解决获得中文参数的乱码
		filename = new String(filename.getBytes("ISO8859-1"),"UTF-8"); //中文.jpg
		
		//获得请求头中的User-Agent 判断浏览器类型
		String agent = request.getHeader("User-Agent");
		//根据不同浏览器进行不同的编码
		String filenameEncoder = "";
		if (agent.contains("MSIE")) {  // 如果是IE浏览器
			filenameEncoder = URLEncoder.encode(filename, "utf-8");
			filenameEncoder = filenameEncoder.replace("+", " ");
		} else if (agent.contains("Firefox")) {  // 如果是火狐浏览器
			BASE64Encoder base64Encoder = new BASE64Encoder();
			filenameEncoder = "=?utf-8?B?" + base64Encoder.encode(filename.getBytes("utf-8")) + "?=";
		} else {  // 其它浏览器
			filenameEncoder = URLEncoder.encode(filename, "utf-8");				
		}

		//告诉客户端,要下载的文件的MIME类型
		response.setContentType(this.getServletContext().getMimeType(filename));
		//告诉客户端该文件不是直接解析,而是以附件形式打开(下载)。 文件名是编码后的文件名,为了防止中文乱码
		response.setHeader("Content-Disposition", "attachment;filename="+filenameEncoder);

		//获取文件的绝对路径
		String path = this.getServletContext().getRealPath("download/"+filename);
		InputStream in = new FileInputStream(path);
		ServletOutputStream out = response.getOutputStream(); // 字节输出流,写给客户端
		
		int len = 0;
		byte[] buffer = new byte[1024];
		while((len=in.read(buffer))>0){
			out.write(buffer, 0, len);
		}

		in.close();
		//out.close();  // Tomcat会帮助自动关闭。

	}

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