1.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 } }
2.If you‘re only interested in the keys, you can iterate through the "keySet()" of the map:
Map<String, Object> map = ...; for (String key : map.keySet()) { // ... }
3.If you only need the values, use "value()":
for (Object value : map.values()) { // ... }
4.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(); // ... }
Summary,If you need only keys or values from the map, use method #2 or method #3. If you are stuck with older version of Java (less than 5) or planning to remove entries during iteration, you have to use method #1. Otherwise use method #4.
How to Iterate Over a Map in Java?
原文：http://www.cnblogs.com/garfieldcgf/p/5829070.html