一期二班 - 吴水金 - 第五课作业

using System;using System.Collections.Generic;using System.Linq;using System.Security.Cryptography;using System.Text;
namespace Hash{    class Program    {        static void Main(string[] args)        {            ConsistencyHash consistencyHash = new ConsistencyHash();            consistencyHash.init();
            int _0 = 0;            int _1 = 0;            int _2 = 0;            int _3 = 0;            int _4 = 0;            int _5 = 0;            int _6 = 0;            int _7 = 0;            int _8 = 0;            int _9 = 0;
            Random ran = new Random();            long startTicks = DateTime.Now.Ticks;
            for (int i = 0; i < 1000000; i++)            {                // 随便取一个数的md5                byte[] ranNum = consistencyHash.computeMd5(i.ToString());
                // 分配到随即的hash环上面                long key = consistencyHash.hash(ranNum, 2);
                if (consistencyHash.getNodeInfo(key).Equals("192.168.0.0-服务器0"))                {                    _0++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.1-服务器1"))                {                    _1++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.2-服务器2"))                {                    _2++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.3-服务器3"))                {                    _3++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.4-服务器4"))                {                    _4++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.5-服务器5"))                {                    _5++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.6-服务器6"))                {                    _6++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.7-服务器7"))                {                    _7++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.8-服务器8"))                {                    _8++;                }                else if (consistencyHash.getNodeInfo(key).Equals("192.168.0.9-服务器9"))                {                    _9++;                }                else                {                    Console.WriteLine("error");                }            }
            // 输出每台服务器负载情况            Console.WriteLine("server_0 = " + _0);            Console.WriteLine("server_1 = " + _1);            Console.WriteLine("server_2 = " + _2);            Console.WriteLine("server_3 = " + _3);            Console.WriteLine("server_4 = " + _4);            Console.WriteLine("server_5 = " + _5);            Console.WriteLine("server_6 = " + _6);            Console.WriteLine("server_7 = " + _7);            Console.WriteLine("server_8 = " + _8);            Console.WriteLine("server_9 = " + _9);
            Console.WriteLine("时长：{0}ms", DateTime.Now.Ticks - startTicks);
            Console.Read();        }    }
    public class ConsistencyHash    {        // 环的所有节点        private SortedList<long, object> allNodes = null;        // 真实服务器节点        private List<Object> realNodes = new List<object>();        // 设置虚拟节点数目        // 太多会影响性能，太少又会导致负载不均衡，一般说来，经验值是150，        // 当然根据集群规模和负载均衡的精度需求，这个值应该根据具体情况具体对待。        private int VIRTUAL_NODE_COUNT = 150;
        public void init()        {            // 加入10台真实服务器            realNodes.Add("192.168.0.0-服务器0");            realNodes.Add("192.168.0.1-服务器1");            realNodes.Add("192.168.0.2-服务器2");            realNodes.Add("192.168.0.3-服务器3");            realNodes.Add("192.168.0.4-服务器4");            realNodes.Add("192.168.0.5-服务器5");            realNodes.Add("192.168.0.6-服务器6");            realNodes.Add("192.168.0.7-服务器7");            realNodes.Add("192.168.0.8-服务器8");            realNodes.Add("192.168.0.9-服务器9");
            // 构造每台真实服务器的虚拟节点            allNodes = new SortedList<long, object>();            for(int i = 0; i < realNodes.Count; i++)            {                object node = realNodes[i];                for(int j = 0; j < VIRTUAL_NODE_COUNT; j++)                {                    var cpm = "NODE-" + i + "-VIRTUAL-" + j;                    var md5 = computeMd5(cpm);                    var hashVal = hash(md5, 0);//使用MD5值计算hash值                    allNodes.Add(hashVal, node);                    //Console.WriteLine(string.Format("{0}\t{1}", cpm, hashVal));                }            }
        }           /**           * 计算MD5值           */            public byte[] computeMd5(String k)          {                MD5 md5 = new MD5CryptoServiceProvider();                byte[] keyBytes = md5.ComputeHash(Encoding.UTF8.GetBytes(k));              md5.Clear();              //md5.update(keyBytes);              //return md5.digest();              return keyBytes;        }
        /**           * 根据2^32把节点分布到环上面           *           * @param digest           * @param nTime           * @return           */            public long hash(byte[] digest, int nTime)          {            long rv = ((long)(digest[3 + nTime * 4] & 0xFF) << 24)                    | ((long)(digest[2 + nTime * 4] & 0xFF) << 16)                    | ((long)(digest[1 + nTime * 4] & 0xFF) << 8)                    | (digest[0 + nTime * 4] & 0xFF);

            return rv & 0xffffffffL; /* Truncate to 32-bits */          }
        /**           * 根据key的hash值取得服务器节点信息           *           * @param hash           * @return           */        public Object getNodeInfo(long hash)          {                string rv;              long key = hash;              //如果找到这个节点，直接取节点，返回                 if (!allNodes.ContainsKey(key))              {                  //得到大于当前key的那个子Map，然后从中取出第一个key，就是大于且离它最近的那个key                  var tailMap = from coll in allNodes                      where coll.Key > hash                      select new {coll.Key};                  if (tailMap == null || tailMap.Count() == 0)                      key = allNodes.FirstOrDefault().Key;                 else                     key = tailMap.FirstOrDefault().Key;             }             return allNodes[key];         }}}