Iterate through a Hashmap

Iterate through the entrySet() like so:

public static void printMap(Map mp) {
Iterator it = mp.entrySet().iterator();
while (it.hasNext()) {
Map.Entry pair = (Map.Entry)it.next();
System.out.println(pair.getKey() + " = " + pair.getValue());
it.remove(); // avoids a ConcurrentModificationException
}
}

4 years ago

If you're only need keys, you can iterate through the keySet() of the map:

Map<String, Object> map = ...;



for (String key : map.keySet()) {

    // ...

}

If you only need the values, use values():

for (Object value : map.values()) {

    // ...

}

Finally, if you want both the key and value, use entrySet():

for (Map.Entry<String, Object> entry : map.entrySet()) {

    String key = entry.getKey();

    Object value = entry.getValue();

}

4 years ago