How do I pass multiple parameter in URL?

Question

I am trying to figure out how to pass multiple parameters in a URL. I want to pass latitude and longitude from my android class to a java servlet. How can I do that?

URL url; double lat=touchedPoint.getLatitudeE6() / 1E6; double lon=touchedPoint.getLongitudeE6() / 1E6; url = new URL("http://10.0.2.2:8080/HelloServlet/PDRS?param1="+lat+lon); 

In this case output (written to file) is 28.53438677.472097. This is working but I want to pass latitude and longitude in two separate parameters so that my work at server side is reduced. If it is not possible how can I at least add a space between lat & lon so that I can use tokenizer class to get my latitude and longitude. I tried following line but to no avail.

    url = new URL("http://10.0.2.2:8080/HelloServlet/PDRS?param1="+lat+" "+lon); output- Nothing is written to file         url = new URL("http://10.0.2.2:8080/HelloServlet/PDRS?param1="+lat+"&?param2="+lon); output- 28.534386 (Only Latitude)         url = new URL("http://10.0.2.2:8080/HelloServlet/PDRS?param1="+lat+"?param2="+lon); output- 28.532577?param2=77.502996 

My servlet code is as follows:

req.setCharacterEncoding("UTF-8"); resp.setCharacterEncoding("UTF-8"); final String par1 =  req.getParameter("param1"); final String par2 = req.getParameter("param2"); FileWriter fstream = new FileWriter("C:\\Users\\Hitchhiker\\Desktop\\out2.txt"); BufferedWriter out = new BufferedWriter(fstream); out.write(par1); out.append(par2); out.close(); 

Also I wanted to the know is this the most safe and secured way to pass the data from android device to server.

Answer 1

This

url = new URL("http://10.0.2.2:8080/HelloServlet/PDRS?param1="+lat+"&param2="+lon); 

must work. For whatever strange reason¹, you need ? before the first parameter and & before the following ones.

Using a compound parameter like

url = new URL("http://10.0.2.2:8080/HelloServlet/PDRS?param1="+lat+"_"+lon); 

would work, too, but is surely not nice. You can't use a space there as it's prohibited in an URL, but you could encode it as %20 or + (but this is even worse style).

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^{1 Stating that ? separates the path and the parameters and that & separates parameters from each other does not explain anything about the reason. Some RFC says "use ? there and & there", but I can't see why they didn't choose the same character.}