几种简单的负载均衡算法及其Java代码实现

https://www.cnblogs.com/szlbm/p/5588555.html

package com.company.com.j.suanfa;

import java.util.*;

public class Test {

    static Integer i = 0;
    public static void main(String[] args) {

        random();
    }

    /**
     * url哈希
     * @param url
     */
    public void hash(String url) {
        Set<String> map = IpMap.serverWeightMap.keySet();
        List<String> list = new ArrayList<String>();
        list.addAll(map);

        int n = url.hashCode() % list.size();
        System.out.println("本次需要IP " + list.get(n));
    }

    /**
     * 随机
     */
    public static void random() {
        Set<String> map = IpMap.serverWeightMap.keySet();
        List<String> list = new ArrayList<String>();
        list.addAll(map);

        //加权
        List<String> listTemp = new ArrayList<String>();
        listTemp.addAll(map);
        for (int j = 0; j < listTemp.size(); j++) {
            int x  = IpMap.serverWeightMap.get(listTemp.get(j));
            for (int k = 0; k < x-1; k++) {
                list.add(listTemp.get(j));
            }
        }

        System.out.println(list);

        int x = new Random().nextInt(list.size());
        System.out.println("本次需要IP " + list.get(x));
    }


    /**
     * 轮询
     */
    public static void lunxun() {
        Set<String> map = IpMap.serverWeightMap.keySet();
        List<String> list = new ArrayList<String>();
        list.addAll(map);

        //加权
        List<String> listTemp = new ArrayList<String>();
        listTemp.addAll(map);
        for (int j = 0; j < listTemp.size(); j++) {
            int x  = IpMap.serverWeightMap.get(listTemp.get(j));
            for (int k = 0; k < x-1; k++) {
                list.add(listTemp.get(j));
            }
        }

        synchronized (i) {
            System.out.println(i+ " _____ IP : " + list.get(i));
            if(i == list.size()-1) {
                i = 0;
            } else {
                i++;
            }
        }
    }


    static class IpMap {
        // 待路由的Ip列表，Key代表Ip，Value代表该Ip的权重
        public static HashMap<String, Integer> serverWeightMap =
                new HashMap<String, Integer>();

        static
        {
            serverWeightMap.put("192.168.1.100", 1);
            serverWeightMap.put("192.168.1.101", 1);
            // 权重为4
            serverWeightMap.put("192.168.1.102", 4);
            serverWeightMap.put("192.168.1.103", 1);
            serverWeightMap.put("192.168.1.104", 1);
            // 权重为3
            serverWeightMap.put("192.168.1.105", 3);
            serverWeightMap.put("192.168.1.106", 1);
            // 权重为2
            serverWeightMap.put("192.168.1.107", 2);
            serverWeightMap.put("192.168.1.108", 1);
            serverWeightMap.put("192.168.1.109", 1);
            serverWeightMap.put("192.168.1.110", 1);
        }
    }
}