Url Parsing in Miranda

Here’s the translation of the Go URL parsing example to Java:

Our URL parsing program demonstrates how to parse URLs in Java. URLs provide a uniform way to locate resources.

import java.net.URI;
import java.net.URISyntaxException;
import java.util.HashMap;
import java.util.Map;

public class URLParsing {
    public static void main(String[] args) {
        // We'll parse this example URL, which includes a
        // scheme, authentication info, host, port, path,
        // query params, and query fragment.
        String s = "postgres://user:pass@host.com:5432/path?k=v#f";

        try {
            // Parse the URL and ensure there are no errors.
            URI uri = new URI(s);

            // Accessing the scheme is straightforward.
            System.out.println(uri.getScheme());

            // UserInfo contains all authentication info; we need to split it
            // to get individual username and password.
            String userInfo = uri.getUserInfo();
            System.out.println(userInfo);
            String[] userInfoParts = userInfo.split(":");
            System.out.println(userInfoParts[0]); // username
            System.out.println(userInfoParts[1]); // password

            // The Host contains both the hostname and the port.
            System.out.println(uri.getHost() + ":" + uri.getPort());
            System.out.println(uri.getHost());
            System.out.println(uri.getPort());

            // Here we extract the path and the fragment after the #.
            System.out.println(uri.getPath());
            System.out.println(uri.getFragment());

            // To get query params in a string of k=v format, use getRawQuery.
            System.out.println(uri.getRawQuery());

            // You can also parse query params into a map.
            Map<String, String> queryParams = parseQuery(uri.getQuery());
            System.out.println(queryParams);
            System.out.println(queryParams.get("k"));

        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
    }

    // Simple method to parse query string into a map
    private static Map<String, String> parseQuery(String query) {
        Map<String, String> queryPairs = new HashMap<>();
        String[] pairs = query.split("&");
        for (String pair : pairs) {
            int idx = pair.indexOf("=");
            queryPairs.put(pair.substring(0, idx), pair.substring(idx + 1));
        }
        return queryPairs;
    }
}

Running our URL parsing program shows all the different pieces that we extracted:

postgres
user:pass
user
pass
host.com:5432
host.com
5432
/path
f
k=v
{k=v}
v

This Java code uses the URI class to parse the URL. The URI class provides methods to access different parts of the URL. For parsing query parameters, we’ve implemented a simple parseQuery method, as Java doesn’t provide a built-in method for this.

Note that Java’s URI class combines the host and port, so we need to call separate methods to get them individually. Also, the UserInfo is returned as a single string, so we need to split it to get the username and password separately.

The overall structure and functionality of the program remain the same as the original, demonstrating how to parse and extract various components of a URL in Java.