How to read request headers from servlets?

Question

Hi We want to know the read request which come from the headers from servlet in java .

Satyapriya Nayak · Answer

Hi Abhishek Reading HTTP request headers from a servlet When a browser requests a web page it generally sends some additional headers which specify things such as: any cookies set for that page; which browser or agent is making request along with information about the operating system  installed browser plugins etc; the referrer (generally the link that the user clicked on that provoked the request); what types of content the browser can deal with. It's beyond the scope of this tutorial to give all the details of every possibly HTTP request header. And it's actually quite rare to need to read request headers. If necessary it is recommended that you look at the HTTP protocol specification if you need more details. However we'll look at a couple of useful cases here by way of example. Reading a request header Usually we'll know the name of the request header that we want to read. In this case it is a simple matter of calling getHeader() on the HttpServletRequest object that was passed to our doGet() / doPost() method. For example here is how to read the user-agent header which essentially tells us which browser (IE Mozilla Safari etc) and operating system is making the request: public final void doGet(HttpServletRequest req HttpServletResponse res) throws ServletException IOException { String agent = req.getHeader(user-agent); if (agent != null && agent.indexOf(MSIE) > -1) { // Internet Explorer mode } else { // Non-Internet Explorer mode } } Note that we should be careful of null values being returned for a given header if it wasn't sent by the client. Note that for a given header knowing what the actual format of data that we might get can be something of a black art and the user-agent string is one of the worst offenders. Please refer the below links http://www.javamex.com/tutorials/servlets/request_headers.shtml http://www.apl.jhu.edu/~hall/java/Servlet-Tutorial/Servlet-Tutorial-Request-Headers.html Thanks Thanks