Consistent Hash Implementation in Java

Reference http://www.codeproject.com/Articles/56138/Consistent-hashing

Get Started

    //initialize 4 service node
    MyServiceNode node1 = new MyServiceNode("IDC1","127.0.0.1",8080);
    MyServiceNode node2 = new MyServiceNode("IDC1","127.0.0.1",8081);
    MyServiceNode node3 = new MyServiceNode("IDC1","127.0.0.1",8082);
    MyServiceNode node4 = new MyServiceNode("IDC1","127.0.0.1",8084);

    //hash them to hash ring
    ConsistentHashRouter<MyServiceNode> consistentHashRouter = new ConsistentHashRouter<>(Arrays.asList(node1,node2,node3,node4),10);//10 virtual nodes

    String requestIp = "192.168.0.1";
    System.out.println(requestIp + " is route to " + consistentHashRouter.routeNode(requestIp));

check sameple of MyServiceNode.java for more details

Developer Doc

Node

Any class that implements Node can be mapped to ConsistentHashRouter.

VirtualNode

Your custom Node represents a real physical node, which supports numbers of virtual nodes , the replicas of physical node.

When adding new Node to the ConsistentHashRouter, you can specify how many virtual nodes should be replicated.

HashFunction

By default , ConsistentHashRouter will use MD5 to hash a node, you may specify your custom hash function by implementing HashFunction

Java 实现的一致性哈希

原理参考 http://www.codeproject.com/Articles/56138/Consistent-hashing

快速开始

    //初始化4个服务节点
    MyServiceNode node1 = new MyServiceNode("IDC1","127.0.0.1",8080);
    MyServiceNode node2 = new MyServiceNode("IDC1","127.0.0.1",8081);
    MyServiceNode node3 = new MyServiceNode("IDC1","127.0.0.1",8082);
    MyServiceNode node4 = new MyServiceNode("IDC1","127.0.0.1",8084);

    //把节点哈希到哈希环中
    ConsistentHashRouter<MyServiceNode> consistentHashRouter = new ConsistentHashRouter<>(Arrays.asList(node1,node2,node3,node4),10);//10个虚拟节点

    String requestIp = "192.168.0.1";
    System.out.println(requestIp + " is route to " + consistentHashRouter.routeNode(requestIp));

更多的使用的实例请参看： MyServiceNode.java

开发者文档

Node（节点）

任意一个实现了Node接口的类的对象都可以映射到ConsistentHashRouter中

VirtualNode（虚拟节点）

自定义的 Node代表一个物理的节点，这些物理节点支持指定一些虚拟节点作为物理节点的复制（replicas）。当需要增加Node 到 ConsistentHashRouter时，你可以指定这个节点需要复制有多少个虚拟节点。

HashFunction（哈希函数）

默认情况下， ConsistentHashRouter 会使用MD5去哈希一个节点，你也可以通过去实现HashFunction指定自己的自定义哈希函数

shadowmodder/ConsistentHash