progrrammer progrrammer - 1 year ago 138
Java Question

Get full URL and query string in Servlet for both HTTP and HTTPS requests

I am writing a code which task is to retrieve a requested URL or full path. I've written this code:

HttpServletRequest request;//obtained from other functions
String uri = request.getRequestURI();
if (request.getQueryString() != null)
uri += "?" + request.getQueryString();

So, when I browse
it is OK (correct).
But there is problem when I browse
. The value of
, So the program doesn't only when
is used.

And the output is same for

What is the solution?

Answer Source

By design, getRequestURL() gives you the full URL, missing only the query string.

In HttpServletRequest, you can get individual parts of the URI using the methods below:

// Example: http://myhost:8080/people?lastname=Fox&age=30

String uri = request.getScheme() + "://" +   // "http" + "://
             request.getServerName() +       // "myhost"
             ":" +                           // ":"
             request.getServerPort() +       // "8080"
             request.getRequestURI() +       // "/people"
             "?" +                           // "?"
             request.getQueryString();       // "lastname=Fox&age=30"
  • .getScheme() will give you "https" if it was a https://domain request.
  • .getServerName() gives domain on http(s)://domain.
  • .getServerPort() will give you the port.

Use the snippet below:

String uri = request.getScheme() + "://" +
             request.getServerName() + 
             ("http".equals(request.getScheme()) && request.getServerPort() == 80 || "https".equals(request.getScheme()) && request.getServerPort() == 443 ? "" : ":" + request.getServerPort() ) +
             request.getRequestURI() +
            (request.getQueryString() != null ? "?" + request.getQueryString() : "");

This snippet above will get the full URI, hiding the port if the default one was used, and not adding the "?" and the query string if the latter was not provided.

Proxied requests

Note, that if your request passes through a proxy, you need to look at the X-Forwarded-Proto header since the scheme might be altered:


Also, a common header is X-Forwarded-For, which show the original request IP instead of the proxys IP. request.getHeader("X-Forwarded-For")

If you are responsible for the configuration of the proxy/load balancer yourself, you need to ensure that these headers are set upon forwarding.

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