Reading request parameters in Google App Engine with Java [duplicate]

问题

I'm modifying the default project that Eclipse creates when you create a new project with Google Web Toolkit and Google App Engine. It is the GreetingService sample project.

How can I read a request parameter in the client's .java file?

For example, the current URL is http://127.0.0.1:8887/MyProj.html?gwt.codesvr=127.0.0.1&foo=bar and I want to use something like request.getParameter("foo") == "bar".

I saw that the documentation mentions the Request class for Python, but I couldn't find the equivalent for Java. It's listed as being in the google.appengine.ext.webapp package, but if I try importing that into my .java file (with a com. prefix), it says that it can't resolve the ext part.

回答1:

Google App Engine uses the Java Servlet API.

GWT's RemoteServiceServlet provides access to the request through:

HttpServletRequest request = this.getThreadLocalRequest();

from which you can call either request.getQueryString(), and interpret the query string any way you desire, or you can call request.getParameter("foo")

回答2:

I was able to get it to work using Window.Location via this answer:

import com.google.gwt.user.client.Window;

// ...

Window.Location.getParameter("foo") // == "bar"

Note that:

Location is a very simple wrapper, so not all browser quirks are hidden from the user.

回答3:

Use java.net.URL to parse the URL and then String.split() to parse the query string.

URL url = new URL("http://127.0.0.1:8887/MyProj.html?gwt.codesvr=127.0.0.1&foo=bar");
String query[] = url.getQuery().split("&");
String foo = null;
for (String arg : query) {
  String s[] = arg.split("=");
  if (s[0].equals("foo"))
    System.out.println(s[1]);
}

See http://ideone.com/Da4fY

来源：https://stackoverflow.com/questions/4514940/reading-request-parameters-in-google-app-engine-with-java

标签

java

google-app-engine

gwt

parameters

httpwebrequest