Question

Is it possible to parse the string keys from a request such as this, with the Java servlet API?

http://localhost:8080/?assocArray[key1]=value1&assocArray[key2]=value2&assocArray[key3]=value3

getParameterValues("assocArray") returns ["value3","value1","value1"]

The ordering of the values in the returned array is not order of the keys (not that it matters)

SOLVED: It is possible, the keys are interpreted as simple global key strings. Java doesn’t recognize them as an array. Use regex

Answer 1

Not directly. The [] have no special meaning in HTTP request parameters and are by the Servlet API not recognized as array keys (you was perhaps a PHP programmer which indeed has a proprietary parser for this?). You need to parse and collect it yourself in a loop.

For example,

Map<String, String> assocArray = new LinkedHashMap<String, String>();

for (Entry<String, String[]> entry : request.getParameterMap().entrySet()) {
    String name = entry.getKey();

    if (name.startsWith("assocArray[")) {
        String key = name.substring(name.indexOf('[') + 1, name.indexOf(']')); 
        assocArray.put(key, entry.getValue()[0]);
    }
}