In java, what's the best way to read a url and split it into its parts?

Question

Firstly, I am aware that there are other posts similar, but since mine is using a URL and I am not always sure what my delimiter will be, I feel that I am alright posting my question. My assignment is to make a crude web browser. I have a textField that a user enters the desired URL into. I then have obviously have to navigate to that webpage. Here is an example from my teacher of what my code would look kinda like. This is the code i'm suposed to be sending to my socket. Sample url: http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol

 GET /wiki/Hypertext_Transfer_Protocol HTTP/1.1\n
Host: en.wikipedia.org\n
\n

So my question is this: I am going to read in the url as just one complete string, so how do I extract just the "en.wikipedia.org" part and just the extension? I tried this as a test:

 String url = "http://en.wikipedia.org/wiki/Hypertext Transfer Protocol";
    String done = " ";
    String[] hope = url.split(".org");

    for ( int i = 0; i < hope.length; i++)
    {
        done = done + hope[i];
    }
    System.out.println(done);

This just prints out the URL without the ".org" in it. I think i'm on the right track. I am just not sure. Also, I know that websites can have different endings (.org, .com, .edu, etc) so I am assuming i'll have to have a few if statements that compenstate for the possible different endings. Basically, how do I get the url into the two parts that I need?

Some answers from https://stackoverflow.com/questions/13592236/parse-a-uri-string-into-name-value-collection are applicable as well — Ilya Serbis, Feb 11 '20 at 22:39

score 46 · Answer 1 · answered Feb 25 '13 at 21:23

46

The URL class pretty much does this, look at the tutorial. For example, given this URL:

http://example.com:80/docs/books/tutorial/index.html?name=networking#DOWNLOADING

This is the kind of information you can expect to obtain:

protocol = http
authority = example.com:80
host = example.com
port = 80
path = /docs/books/tutorial/index.html
query = name=networking
filename = /docs/books/tutorial/index.html?name=networking
ref = DOWNLOADING

answered Feb 25 '13 at 21:23

Óscar López

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awesome! thanks. I really need to get to know my Classes better – art3m1sm00n Feb 25 '13 at 21:26
@GabrielleLee you're welcome! if this answer was helpful for you, please don't forget to accept it by clicking on the check mark to its left ;) – Óscar López Feb 25 '13 at 21:27

score 1 · Answer 2 · answered Feb 25 '13 at 21:23

1

This is how you should split your URL parts: http://docs.oracle.com/javase/tutorial/networking/urls/urlInfo.html

answered Feb 25 '13 at 21:23

piokuc

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score 1 · Answer 3 · edited May 23 '17 at 10:29

1

Instead of url.split(".org"); try url.split("/"); and iterate through your array of strings.

Or you can look into regular expressions. This is a good example to start with.

Good luck on your homework.

edited May 23 '17 at 10:29

Community

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answered Feb 25 '13 at 21:26

Reza Shirazian

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Use the specifically designed URL. It will handle many edge cases that are difficult with simple split, or regex. – Mikezx6r Feb 04 '21 at 14:47

score 1 · Answer 4 · answered Nov 06 '21 at 14:43

Even though the answer with URL class is great, here is one more way to split URL to components using REGEXP:

"^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?"
      ||            |  |          |       |   |        | |
      12 - scheme   |  |          |       |   |        | |
                    3  4 - authority, includes hostname/ip and port number.
                                  5 - path|   |        | |
                                          6   7 - query| |
                                                       8 9 - fragment

You can use it with Pattern class:

var regex = "^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?";
var pattern = Pattern.compile(REGEX);
var matcher = pattern.matcher("http://example.com:80/docs/books/tutorial/index.html?name=networking#DOWNLOADING");
if (matcher.matches()) {
  System.out.println("scheme: " + matcher.group(2));
  System.out.println("authority: " + matcher.group(4));
  System.out.println("path: " + matcher.group(5));
  System.out.println("query: " + matcher.group(7));
  System.out.println("fragment: " + matcher.group(9));
}

score -1 · Answer 5 · edited Feb 07 '19 at 10:36

you can use String class split() and store the result into the String array then iterate the array and store the variable and value into the Map.

public class URLSPlit {
    public static Map<String,String> splitString(String s) {
        String[] split = s.split("[= & ?]+");
        int length = split.length;
        Map<String, String> maps = new HashMap<>();

        for (int i=0; i<length; i+=2){
              maps.put(split[i], split[i+1]);
        }

        return maps;
    }

    public static void main(String[] args) {
        String word = "q=java+online+compiler&rlz=1C1GCEA_enIN816IN816&oq=java+online+compiler&aqs=chrome..69i57j69i60.18920j0j1&sourceid=chrome&ie=UTF-8?k1=v1";
        Map<String, String> newmap =  splitString(word);

        for(Map.Entry map: newmap.entrySet()){
            System.out.println(map.getKey()+"  =  "+map.getValue());
        }
    }
}

Use the specifically designed URL. It will handle many edge cases that are difficult with simple split, or regex. — Mikezx6r, Feb 04 '21 at 14:48

In java, what's the best way to read a url and split it into its parts?

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