架构师训练营 - 第五周作业

public class HashFunction {
    public Integer hash(String key) {
        final int p = 16777619;        int hash = (int)2166136261L;        for (int i = 0; i < key.length(); i++)            hash = (hash ^ key.charAt(i)) * p;        hash += hash << 13;        hash ^= hash >> 7;        hash += hash << 3;        hash ^= hash >> 17;        hash += hash << 5;
        // 如果算出来的值为负数则取其绝对值        if (hash < 0)            hash = Math.abs(hash);        return hash;    }}

public class Node {
    private String ip;    private String name;
    public Node(String ip, String name) {        this.ip = ip;        this.name = name;    }
    public String getIp() {        return ip;    }
    public void setIp(String ip) {        this.ip = ip;    }
    public String getName() {        return name;    }
    public void setName(String name) {        this.name = name;    }}

import java.util.Collection;import java.util.SortedMap;import java.util.TreeMap;
public class ConsistentHash {
    private final HashFunction hashFunction;    private final int numberOfReplicas;    private final SortedMap<Integer, Node> circle = new TreeMap<>();
    public ConsistentHash(HashFunction hashFunction, int numberOfReplicas, Collection<Node> nodes) {        this.hashFunction = hashFunction;        this.numberOfReplicas = numberOfReplicas;
        for (Node node : nodes) {            add(node);        }    }
    public void add(Node node) {        for (int i = 0; i < this.numberOfReplicas; i++) {            circle.put(this.hashFunction.hash(node.getIp() + i), node);        }    }
    public void remove(Node node) {        for (int i = 0; i < this.numberOfReplicas; i++) {            circle.remove(this.hashFunction.hash(node.getIp() + i));        }    }
    public Node get(String key) {        if (circle.isEmpty()) {            return null;        }        Integer hash = hashFunction.hash(key);        if (!circle.containsKey(hash)) {            SortedMap<Integer, Node> tailMap = circle.tailMap(hash);            hash = tailMap.isEmpty() ? circle.firstKey() : tailMap.firstKey();        }        return circle.get(hash);    }}

import java.util.*;
public class Test {
    private static final String IP_PREFIX = "192.168.1.";    public static void main(String[] args) {        Map<String, Integer> map = new HashMap<String, Integer>();        HashFunction hashFunction = new HashFunction();        List<Node> realNodes = new ArrayList<>();        for (int i = 1; i <= 10; i++) {            map.put(IP_PREFIX + i, 0);            Node node = new Node(IP_PREFIX + i, "node" + i);            realNodes.add(node);        }        ConsistentHash consistentHash = new ConsistentHash(hashFunction,100,realNodes);        for (int i = 0; i < 1000000; i++) {            String data = UUID.randomUUID().toString() + i;            Node node = consistentHash.get(data);            map.put(node.getIp(), map.get(node.getIp()) + 1);        }
        for (int i = 1; i <= 10; i++) {            System.out.println(IP_PREFIX + i + "节点记录条数：" + map.get("192.168.1." + i));        }    }}