以字符串形式返回Multimap ArrayList

Question

public static String getMRIScanSite(String val) {
    Multimap<String, String> map = HashMultimap.create();
    map.put("01", "131");
    map.put("04", "157");
    map.put("01", "158");
    map.put("109", "169");
    map.put("112", "170");

    Multimap<String, String> invertedMap = Multimaps.invertFrom(map, ArrayListMultimap.<String, String>create());
    return String.valueOf(invertedMap.get(val));
}

Is there any method to return multimap ArrayList to String ? I tried to convert to String using String.valueOf(), But result still in array. Thank you

current output :

"mriScansSite": "[01]"

expected output:

 "mriScansSite": "01"

Answer 1

Try this:

return String.join(",", invertedMap.get(val));

In case invertedMap.get(..) returns an ArrayList with multiple values, they are separated by ",".