下载文件时文件名中文乱码问题

通过User-Agent请求头判断当前浏览器类型

• Chrome
  • Chrome：User-Agen中含有"Chrome"字符串
  • User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36
  • 解决方式：fileName = new String(fileName .getBytes("UTF-8"), "ISO8859-1");
• IE
  • IE浏览器：User-Agent中含有"Trident"字符串
  • User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
  • 解决方式：fileName = URLEncoder.encode(fileName, "UTF-8").replace("+", "%20");
• Firefox
  • Firefox：User-Agent中含有"Firefox"字符串
  • User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:56.0) Gecko/20100101 Firefox/56.0
  • 解决方式：fileName = "=?utf-8?b?"+new BASE64Encoder().encode(fileName .getBytes("utf-8"))+"?=";
• Edge
  • Edge：User-Agent中含有"Edge"字符串
  • User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Edge/15.15063
  • 解决方式：fileName = URLEncoder.encode(fileName, "UTF-8").replace("+", "%20");
• 其他浏览器
  • 解决方式（仍然存在部分中文乱码问题）：fileName = new String(fileName .getBytes("gbk"),"ISO8859-1");

getBytes(String charsetName): 使用指定的字符集将字符串编码为 byte 序列，并将结果存储到一个新的 byte 数组中。

new String(byte[], decode)：使用指定的编码 decode 来将 byte[] 解析成字符串。

模板代码：

String fileName = "盗将行.mp3";
String userAgent = request.getHeader("User-Agent");
if ("Edge".contains(userAgent)) {
 	fileName = URLEncoder.encode(fileName, "UTF-8").replace("+", "%20");
}else if ("Chrome".contains(userAgent)) {
 	fileName = new String(fileName.getBytes("UTF-8"), "ISO8859-1");
}else if ("Firefox".contains(userAgent)) {
 	fileName = "=?utf-8?b?"+new BASE64Encoder().encode(fileName.getBytes("utf-8"))+"?=";
}else if ("Trident".contains(userAgent)) {
 	fileName = URLEncoder.encode(fileName, "UTF-8").replace("+", "%20");
}else {
 	fileName = new String(fileName.getBytes("gbk"),"ISO8859-1");
}