javaweb文件下载及文件名中文乱码处理

文件下载

需要先导入两个jar包
commons-fileupload-1.3.1.jar
commons-io-2.4.jar

 String fileName = request.getParameter("fileName");
   //下载文件，需要设置两个响应头
   //application/octet-stream任意文件类型
   response.addHeader("content-Type", "application/octet-stream");
   //对于不同浏览器进行处理
   //根据请求头user-agent
   //attachment打开对话框下载  inline直接打开
   String agent = request.getHeader("User-agent");
   if(agent.indexOf("Firefox")!=-1) {
    response.addHeader("content-Disposition", "attachment;fileName==?UTF-8?B?"+Base64.getEncoder().encodeToString(fileName.getBytes("utf-8"))+"?=");
   }else if(agent.indexOf("Edge")!=-1) {
    response.addHeader("content-Disposition", "attachment;fileName="+URLEncoder.encode(fileName, "utf-8"));
   }
   //servlet 通过文件路径将文件转换为输入流 读到servlet中
   InputStream in = getServletContext().getResourceAsStream("/res/"+fileName);
   //输出流
   ServletOutputStream out = response.getOutputStream();
   byte[] bt = new byte[10];
   int len = -1;
   //将缓冲区的读取bt
   while((len=in.read(bt))!=-1) {
    //将bt里的输出到response
    out.write(bt,0,len);
   }
   out.close();
   in.close();

文件下载名中文乱码问题

(1).edge

response.addHeader("content-Disposition", "attachment;fileName="+URLEncoder.encode(fileName, "utf-8"));

(2).火狐

response.addHeader("content-Disposition", "attachment;fileName==?UTF-8?B?"+Base64.getEncoder().encodeToString(fileName.getBytes("utf-8"))+"?=");

(3).综合处理

   String agent = request.getHeader("User-agent");
   if(agent.indexOf("Firefox")!=-1) {
    response.addHeader("content-Disposition", "attachment;fileName==?UTF-8?B?"+new String(Base64.encodeBase64(fileName.getBytes("utf-8")))+"?=");
   }else if(agent.indexOf("Edge")!=-1) {
    response.addHeader("content-Disposition", "attachment;fileName="+URLEncoder.encode(fileName, "utf-8"));
   }