What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

Question

I\'m making a simple, very lightweight front-controller. I need to match request paths to different handlers (actions) in order to choose the correct one.

On my loca

Answer 1

getPathInfo() gives the extra path information after the URI, used to access your Servlet, where as getRequestURI() gives the complete URI.

I would have thought they would be different, given a Servlet must be configured with its own URI pattern in the first place; I don't think I've ever served a Servlet from root (/).

For example if Servlet 'Foo' is mapped to URI '/foo' then I would have thought the URI:

/foo/path/to/resource

Would result in:

RequestURI = /foo/path/to/resource

and

PathInfo = /path/to/resource

Answer 2

I will put a small comparison table here (just to have it somewhere):

Servlet is mapped as /test%3F/* and the application is deployed under /app.

http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S%3F+ID?p+1=c+d&p+2=e+f#a

Method              URL-Decoded Result           
----------------------------------------------------
getContextPath()        no      /app
getLocalAddr()                  127.0.0.1
getLocalName()                  30thh.loc
getLocalPort()                  8480
getMethod()                     GET
getPathInfo()           yes     /a?+b
getProtocol()                   HTTP/1.1
getQueryString()        no      p+1=c+d&p+2=e+f
getRequestedSessionId() no      S%3F+ID
getRequestURI()         no      /app/test%3F/a%3F+b;jsessionid=S+ID
getRequestURL()         no      http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S+ID
getScheme()                     http
getServerName()                 30thh.loc
getServerPort()                 8480
getServletPath()        yes     /test?
getParameterNames()     yes     [p 2, p 1]
getParameter("p 1")     yes     c d

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In the example above the server is running on the localhost:8480 and the name 30thh.loc was put into OS hosts file.

Comments

• "+" is handled as space only in the query string

• Anchor "#a" is not transferred to the server. Only the browser can work with it.

• If the url-pattern in the servlet mapping does not end with * (for example /test or *.jsp), getPathInfo() returns null.

If Spring MVC is used

• Method getPathInfo() returns null.

• Method getServletPath() returns the part between the context path and the session ID. In the example above the value would be /test?/a?+b

• Be careful with URL encoded parts of @RequestMapping and @RequestParam in Spring. It is buggy (current version 3.2.4) and is usually not working as expected.

Answer 3

Let's break down the full URL that a client would type into their address bar to reach your servlet:

http://www.example.com:80/awesome-application/path/to/servlet/path/info?a=1&b=2#boo

The parts are:

1. scheme: http
2. hostname: www.example.com
3. port: 80
4. context path: awesome-application
5. servlet path: path/to/servlet
6. path info: path/info
7. query: a=1&b=2
8. fragment: boo

The request URI (returned by getRequestURI) corresponds to parts 4, 5 and 6.

(incidentally, even though you're not asking for this, the method getRequestURL would give you parts 1, 2, 3, 4, 5 and 6).

Now:

• part 4 (the context path) is used to select your particular application out of many other applications that may be running in the server
• part 5 (the servlet path) is used to select a particular servlet out of many other servlets that may be bundled in your application's WAR
• part 6 (the path info) is interpreted by your servlet's logic (e.g. it may point to some resource controlled by your servlet).
• part 7 (the query) is also made available to your servlet using getQueryString
• part 8 (the fragment) is not even sent to the server and is relevant and known only to the client

The following always holds (except for URL encoding differences):

requestURI = contextPath + servletPath + pathInfo

The following example from the Servlet 3.0 specification is very helpful:

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Note: image follows, I don't have the time to recreate in HTML:

Answer 4

Consider the following servlet conf:

   <servlet>
        <servlet-name>NewServlet</servlet-name>
        <servlet-class>NewServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>NewServlet</servlet-name>
        <url-pattern>/NewServlet/*</url-pattern>
    </servlet-mapping>

Now, when I hit the URL http://localhost:8084/JSPTemp1/NewServlet/jhi, it will invoke NewServlet as it is mapped with the pattern described above.

Here:

getRequestURI() =  /JSPTemp1/NewServlet/jhi
getPathInfo() = /jhi

We have those ones:

• getPathInfo()

  returns
  a String, decoded by the web container, specifying extra path information that comes after the servlet path but before the query string in the request URL; or null if the URL does not have any extra path information

• getRequestURI()

  returns
  a String containing the part of the URL from the protocol name up to the query string