package collectionUtils;import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;public class MyMap<K, V> {private Map<K, V> kMap = new HashMap<K, V>();private Map<V, ConcurrentHashMap<K, String>> vMap = new HashMap<V, ConcurrentHashMap<K, String>>();private final static String VV = "1";public boolean put(K k, V v) {boolean result = false;if (k == null || v == null) {return result;}if (kMap.containsKey(k)) {//更新键值对vMap.get(kMap.get(k)).remove(k);// vMap.remove(kMap.get(k));}kMap.put(k, v);if (vMap.containsKey(v)) {vMap.get(v).put(k, VV);} else {ConcurrentHashMap<K, String> set = new ConcurrentHashMap<K, String>();set.put(k, VV);vMap.put(v, set);}return true;}public boolean containsKey(K k) {return kMap.containsKey(k);}public boolean containsValue(V v) {return vMap.containsKey(v);}public Set<K> keySet() {return kMap.keySet();}public Set<V> valueSet() {return vMap.keySet();}public V getByKey(K k) {return kMap.get(k);}public ConcurrentHashMap<K, String> getByValue(V v) {return vMap.get(v);}public String toString() {return kMap.toString();}public static void main(String[] args) {MyMap<String, String> map = new MyMap<String, String>();map.put("k1", "v1");map.put("k2", "v2");map.put("k3", "v1");map.put("k4", "v2");System.out.println("k1 -> " + map.getByKey("k1"));System.out.println("v1 -> " + map.getByValue("v1").keySet());System.out.println("v2 -> " + map.getByValue("v2").keySet());map.put("k5", "v2");System.out.println("v2 -> " + map.getByValue("v2").keySet());map.put("k5", "v1");System.out.println("v1 -> " + map.getByValue("v1").keySet());System.out.println("v2 -> " + map.getByValue("v2").keySet());// 替换所有的v1为v111System.out.println("before update : " + map);for (String k : map.getByValue("v1").keySet()) {map.put(k, "v111");}System.out.println("after update : " + map);}
}