最简单的一致性Hash算法实现

import java.util.Collection;import java.util.SortedMap;import java.util.TreeMap;

public class ConsistentHash<T> {

 private final HashFunction hashFunction; private final int numberOfReplicas; private final SortedMap<Integer, T> circle = new TreeMap<Integer, T>();

 public ConsistentHash(HashFunction hashFunction, int numberOfReplicas,     Collection<T> nodes) {   this.hashFunction = hashFunction;   this.numberOfReplicas = numberOfReplicas;

   for (T node : nodes) {     add(node);   } }

 public void add(T node) {   for (int i = 0; i < numberOfReplicas; i++) {     circle.put(hashFunction.hash(node.toString() + i), node);   } }

 public void remove(T node) {   for (int i = 0; i < numberOfReplicas; i++) {     circle.remove(hashFunction.hash(node.toString() + i));   } }

 public T get(Object key) {   if (circle.isEmpty()) {     return null;   }   int hash = hashFunction.hash(key);   if (!circle.containsKey(hash)) {     SortedMap<Integer, T> tailMap = circle.tailMap(hash);     hash = tailMap.isEmpty() ? circle.firstKey() : tailMap.firstKey();   }   return circle.get(hash); }

}

最简单的一致性Hash算法实现