Getting part of request url inside servlet

问题:

I have an EmailVerification Servlet mapped with /ev/* url-pattern.

http://example.com/ev/ce52320570

How can I get this ce52320570 part of the URL in my Servlet?

protected void doPost(HttpServletRequest request, HttpServletResponse response)
                                                     throws ServletException, IOException {
      String vid = "";  // Here I need to get the id from the URL
}

回答1:

Considering a Servlet (called EmailVerification) mapped to /ev/*:

Will the URL http://example.com/ev/ce52320570 trigger the EmailVerification servlet ?

Yes. In Servlet versions 2.5 and 3.0 (maybe earlier), it'll get the subpath if you map it with *, like /ev/*, as you did.

How can I get this ce52320570 part of the URL http://example.com/ev/ce52320570?

• request.getRequestURI() will get you the requested URL as a String, like /ev/ce52320570.

• request.getPathInfo() gets you (if exists) everything after /ev/.

  • So in a request to /ev/123, getPathInfo() would give you /123. The same way, a request to /ev/some/other, getPathInfo() would give you /some/other.

• request.getQueryString() should be used if you need the query parameters part of the URL.

  • Keep in mind both getRequestURI() and getPathInfo() give you only the path requested. If you need to obtain the query parameters, that is, those after the ?, like /ev/something?query1=value1&other=123, only request.getQueryString() would return the query1=value1&other=123 part.

• request.getParameter(parameterName) if you need the value of a specific query parameter.

  • Resort to .getParameterValues() if it is a multivalued parameter

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More examples of the URL parts in the request here.

回答2:

Use request.getRequestURI() and remove what you don't need, i.e. request.getRequestURI().replace("/ev/");