导入：上个星期五加班到很晚(且用了同事的ios手机做测试)，在为解决一个bug而烦恼，不知道怎么修，从网上找过资料，但是并没解决方案，且有其他人遇到此问题，但并没人解决，因此写下这篇文章记录一下。

ios13企业微信点击pdf页面直接乱码了

客户的USER-AGENT

agentMozilla/5.0 (iPhone; CPU iPhone OS 13_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 wxwork/3.0.14 MicroMessenger/7.0.1 Language/zh

点击下载的pdf的后台接口逻辑

OutputStream os = null;
BufferedInputStream reader = null;
try {
	ParamsTable params = this.getParams();
	HttpServletRequest request = ServletActionContext.getRequest();
	HttpServletResponse response = ServletActionContext.getResponse();
	String encoding = "ISO-8859-1";
	String filename = params.getParameterAsString("filename");
	String filepath = params.getParameterAsString("filepath");
	if(!filepath.startsWith("/uploads/")){
		response.getWriter().print("Error: file illegal!");
		return NONE;
	}
	filepath = URLDecoder.decode(filepath, encoding);
	String realPath = request.getSession().getServletContext().getRealPath("/");
	File file = new File(realPath + filepath);
	if(!file.exists()){
		return "找不到指定文件";
	}
	
	String agent = request.getHeader("USER-AGENT");
	
	response.setContentType("application/octet-stream;charset=ISO-8859-1");
	if(null != agent){
		if(-1 != agent.indexOf("Firefox")) {
			response.setHeader("Content-Disposition", "attachment;filename=\"" + MimeUtility.encodeText(filename, encoding, "B") + "\"");
		} else if(-1 != agent.indexOf("Trident") || -1 != agent.indexOf("MSIE")) {
			response.setHeader("Content-Disposition", "attachment;filename=\"" + filename + "\"");
		} else {
			
			response.setHeader("Content-Disposition", "attachment;filename=\"" + URLDecoder.decode(filename, encoding) + "\"");
		}
	} else {
		response.setHeader("Content-Disposition", "attachment;filename=\"" + URLDecoder.decode(filename, encoding) + "\"");
	}

	os = response.getOutputStream();

	reader = new BufferedInputStream(new FileInputStream(file));
	IOUtils.copy(reader, os);
} catch (IOException e) {
	e.printStackTrace();
	return "下载失败";
} finally {
	try{
		if (os != null) {
			reader.close();
		}
		if ( reader != null) {
			reader.close();
		}
	} catch(Exception e) {
		e.printStackTrace();
	}
}

看了很久，用流的形式去下载pdf一直有问题，而安卓上是没有问题，因此很难看到问题，后来，我更改他的下载的方式，直接返回路径给客户端，这样能成功了。
加多这两行代码：

if(agent.indexOf("iPhone")>0 && agent.indexOf("13")>0 ){
	String contextPath = request.getContextPath();
	response.sendRedirect(contextPath+filepath);
}

总结

并没找到具体的原因，有点可惜。但能解决到客户的问题，也是挺不错的。