利用response和HttP中的Content-Disposition: attachment; filename=aaa.zip响应头，实现简单的文件下载

中文名称的文件下载需要注意的问题：

  1、在设置response响应为Content-Disposition: attachment; filename=aaa.zip，通知浏览器以下载的方式处理服务器发来的数据。

  2、对于中文名称的文件，需要利用URLEncoder.encode(filename,"utf-8"),对中文进行编码，即可

完整的文件下载程序如下package com.baowei.servletimport java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.Properties;

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

import com.baowei.persondao.PersonDao;

public class FristServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {

        doGet(req, resp);

    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {

        fileDownload(resp);

    }

    private void fileDownload(HttpServletResponse resp) throws IOException {
        
        ServletContext context = this.getServletContext();
        String realpath = context.getRealPath("/哈哈.png");
        
        String filename = realpath.substring(realpath.lastIndexOf("\") + 1);
        System.out.println(filename);

        // resp.setContentType("image/png"); ，用于图片的显示 
       

        //中文的文件名需要进行URLEncoder.encode(filename,"utf-8")的处理
        resp.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(filename,"utf-8"));
        
        FileInputStream is = new FileInputStream(realpath);
        byte[] buffer = new byte[1024];
        int len = 0;

        OutputStream out = resp.getOutputStream();
        while ((len = is.read(buffer)) != -1) {
            out.write(buffer, 0, len);
        }
        out.flush();
        is.close();

    }

}