【架构师训练营 - week5 -1】作业

import org.apache.commons.lang3.RandomStringUtils;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;
public class ConsistentHashTest {
    @Test
    public void test() {
        List<String> list = new ArrayList<>();
        for (int i = 0; i < 1000000; i++) {
            String key = RandomStringUtils.randomAlphanumeric(10);
            list.add(key);
        }
        ConsistentHash consistentHash = new ConsistentHash();
        consistentHash.consistent(list);
    }
}

import com.google.common.hash.Hashing;
import java.nio.charset.Charset;
import java.util.*;
public class ConsistentHash {
    static List<String> servers = new ArrayList<>();
    static Map<Integer, Integer> map = new TreeMap<>();
    public void consistent(List<String> keys) {
        init();
        for (String server : servers) {
            for (int i = 0; i < 100; i++) {
                String vm = server + "#" + i;
                map.put(Hashing.murmur3_32().hashString(vm, Charset.forName("utf-8")).asInt(), 0);
            }
        }
        for (String key : keys) {
            for (Integer i : map.keySet()) {
                if (Hashing.murmur3_32().hashString(key, Charset.forName("utf-8")).asInt() < i) {
                    map.put(i, map.getOrDefault(i, 0) + 1);
                }
            }
        }
        int[] data = new int[map.keySet().size()];
        int i = 0;
        for (int key : map.keySet()) {
            data[i++] = map.get(key);
        }
        System.out.println(standardDeviation(data));
    }
    public void init() {
        for (int i = 0; i < 10; i++) {
            servers.add("192.168.0." + i);
        }
    }
    public static double standardDeviation(int[] x) {
        int m = x.length;
        double sum = 0;
        for (int i = 0; i < m; i++) {
            sum += x[i];
        }
        double dAve = sum / m;
        double dVar = 0;
        for (int i = 0; i < m; i++) {
            dVar += (x[i] - dAve) * (x[i] - dAve);
        }
        return Math.sqrt(dVar / m);
    }
    public static void main(String[] args) {
        Map<Integer, Integer> map1 = new TreeMap<>();
        map1.put(5,2);
        map1.put(3,2);
        map1.put(1,2);
        map1.put(2,2);
        for (Integer i : map1.keySet()){
            System.out.println(i);
        }
    }
}