import java.util.HashMap;

import java.util.Map;

public class UrlParameterSplitter {

/**

* Splits URL parameters into a map. Handles backward compatibility by

* providing default values if parameters are missing or null.

*

* @param urlParams A string containing URL parameters (e.g., "param1=value1&param2=value2").

* @param defaultValues A map containing default values for parameters.

* @return A map containing the URL parameters and their values.

*/

public static Map<String, String> splitUrlParams(String urlParams, Map<String, String> defaultValues) {

Map<String, String> params = new HashMap<>();

if (urlParams == null || urlParams.isEmpty()) {

return defaultValues; // Return default values if no parameters are provided.

}

String[] pairs = urlParams.split("&");

for (String pair : pairs) {

if (pair == null || pair.isEmpty()) {

continue; // Skip empty pairs

}

String[] parts = pair.split("=");

if (parts.length == 2) {

String key = parts[0];

String value = parts[1];

params.put(key, value);

} else if (parts.length == 1) {

//Handle cases like "param_without_value" - use the default value

String key = parts[0];

String defaultValue = defaultValues.getOrDefault(key, ""); // Use default value if key not found

params.put(key, defaultValue);

} else {

//Handle invalid parameter format (more than one '=' sign) - use the default value

String key = pair;

String defaultValue = defaultValues.getOrDefault(key, "");

params.put(key, defaultValue);

}

}

return params;

}

public static void main(String[] args) {

// Example usage

String urlParams = "param1=value1&param2=value2&param3";

Map<String, String> defaultValues = new HashMap<>();

defaultValues.put("param1", "default_value_1");

defaultValues.put("param2", "default_value_2");

defaultValues.put("param3", "default_value_3");

Map<String, String> parsedParams = splitUrlParams(urlParams, defaultValues);

System.out.println(parsedParams);

}

}