如何更改 HttpServletRequest 的用户代理？

Question

my application is using HttpServletRequest to send a webservice request. when i run the request from our application in ie11 i get no results returned, but when i run it from Firefox i get results back. this is what aRequest.getHeader("User-Agent") current value

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; InfoPath.2; .NET CLR 1.1.4322; MS-RTC LM 8)

i need to change this to ie11 compatibilty. it looks like the user agent in the request is for ie7.0 the problem is i dont see any options for 'setHeader'. i only see option for aRequest.setAttribute i have tried setting attribute but that did not work

 public final ActionForward execute(final ActionMapping aMapping,
                             final ClientForm aForm,
                             final HttpServletRequest aRequest,
                             final HttpServletResponse aResponse)
                  throws ServletException
{
    try {

        final ServletOutputStream out = aResponse.getOutputStream(); 
        aResponse.setContentType("text/html");
        processAjaxRequest(aMapping, aForm, aRequest, aResponse, out);
         out.flush();
        out.close();
    }

 public void processAjaxRequest(final ActionMapping aMapping,
                                 final ClientForm aForm,
                                 final HttpServletRequest aRequest,
                                 final HttpServletResponse aResponse,
                                 final ServletOutputStream out)
                      throws ServletException, IOException
    {

            String response = null;
            boolean isValid = false;

            if (isValid(aRequest, aForm)) { 
                response = "success";
                isValid = true;
            } else {
                response = "fail";
                isValid = false;
            }
            if (WebUtils.getParameter(aRequest, "format", "html").equals("json")) {
                //Map<String,String> map = new HashMap<String,String>(1);
                Map map = new HashMap(1);
                map.put("status", isValid ? "ok" : "fail");
                aResponse.setHeader("X-JSON", JSON.encode(map));
            } else {
                out.print(response);
            }        
    }

Answer 1

my application is using HttpServletRequest to send a webservice request.

Your application is webservice. Webservice doesn't send request, it receive requests from the client.

HttpServletRequest is request from your client (browser in your case). You shouldn't change it, for you servlet it's just "read-only" input data to handle.

Browser send such user-agent for some historical reason ( more details here ). But "compatible; MSIE 7.0;" in user-agent request has nothing common with your problem with ie11.

You should investigate deeper reason, why ie11 doesn't work. Look at console in browser (any errors?) or debugging your service code.

I see, that you write response "out.print(response);" only in "else" case of your condition, may be it's a reason. So, if condition is true, your code doesn't send body (only "X-JSON" header).