java笔记-代码简单实现负载均衡

本文使用java代码实现简单的负载均衡

服务器负载均衡选择

• 随机法
• 加权随机法
• 轮训法
• 加权轮训法

废话不多说，直接撸代码：

模拟的服务器地址池：

    static class IpMap {
        public static HashMap<String, Integer> serverWeightMap = new HashMap<String, Integer>();
        static {
            serverWeightMap.put("192.168.30.201", 1);
            serverWeightMap.put("192.168.30.202", 2);
            serverWeightMap.put("192.168.30.203", 3);
            serverWeightMap.put("192.168.30.204", 4);
            serverWeightMap.put("192.168.30.205", 2);
            serverWeightMap.put("192.168.30.206", 1);
            serverWeightMap.put("192.168.30.207", 5);
        }
    }

1、轮训法

static class RoundRobin {
        private static Integer pos = 0;

        public static String getServer() {
            Map<String, Integer> serverMap = new HashMap<String, Integer>();
            serverMap.putAll(IpMap.serverWeightMap);

            Set<String> keySet = serverMap.keySet();

            List<String> keyList = new ArrayList<String>();

            keyList.addAll(keySet);

            String server;
            synchronized (pos) {
                if (pos > keySet.size()) {
                    pos = 0;
                }
                server = keyList.get(pos);
                pos++;
            }
            return server;
        }
    }

2、随机法

static class Random {
        public static String getServer() {
            Map<String, Integer> serverMap = new HashMap<String, Integer>();
            serverMap.putAll(IpMap.serverWeightMap);
            Set<String> keySet = serverMap.keySet();
            List<String> keyList = new ArrayList<String>();
            keyList.addAll(keySet);
            java.util.Random random = new java.util.Random();
            int pos = random.nextInt(keyList.size());
            return keyList.get(pos);
        }


    }

3、加权轮训法

static class WeightRounRabin {
        private static Integer pos = 0;

        public static String getServer() {
            Map<String, Integer> serverMap = new HashMap<String, Integer>();
            serverMap.putAll(IpMap.serverWeightMap);

            Set<String> keySet = serverMap.keySet();
            List<String> keyList = new ArrayList<String>();

            Iterator<String> iterator = keySet.iterator();
            while (iterator.hasNext()) {
                String server = iterator.next();
                int weight = serverMap.get(server);
                for (int i = 0; i < weight; i++) {
                    keyList.add(server);
                }
            }
            String server;
            synchronized (pos) {
                if (pos > keySet.size()) {
                    pos = 0;
                }
                server = keyList.get(pos);
                pos++;
            }
            return server;
        }
    }

4、加权随机法

static class WeightRandom {
        public static String getServer() {
            Map<String, Integer> serverMap = new HashMap<String, Integer>();
            serverMap.putAll(IpMap.serverWeightMap);

            Set<String> keySet = serverMap.keySet();
            List<String> keyList = new ArrayList<String>();

            Iterator<String> iterator = keySet.iterator();
            while (iterator.hasNext()) {
                String server = iterator.next();
                int weight = serverMap.get(server);
                for (int i = 0; i < weight; i++) {
                    keyList.add(server);
                }
            }

            java.util.Random random = new java.util.Random();
            int pos = random.nextInt(keyList.size());
            return keyList.get(pos);
        }


    }

相信聪明的你早已看懂....