java编写一个负载均衡中的权重分配算法

以下是一个简单的Java代码示例，用于实现加权轮询（Weighted Round Robin）算法：

import java.util.ArrayList;
import java.util.List;

public class WeightedRoundRobin {

    private List<Server> serverList;
    private int currentIndex = -1;
    private int currentWeight = 0;
    private int maxWeight = 0;
    private int gcdWeight = 0;

    public WeightedRoundRobin(List<Server> servers) {
        this.serverList = servers;
        for (Server server : serverList) {
            maxWeight = Math.max(maxWeight, server.weight);
        }
        gcdWeight = gcdWeight();
    }

    public Server nextServer() {
        while (true) {
            currentIndex = (currentIndex + 1) % serverList.size();
            if (currentIndex == 0) {
                currentWeight -= gcdWeight;
                if (currentWeight <= 0) {
                    currentWeight = maxWeight;
                    if (currentWeight == 0) {
                        return null;
                    }
                }
            }
            if (serverList.get(currentIndex).weight >= currentWeight) {
                return serverList.get(currentIndex);
            }
        }
    }

    private int gcdWeight() {
        int weight = 0;
        for (Server server : serverList) {
            weight = gcd(weight, server.weight);
        }
        return weight;
    }

    private int gcd(int a, int b) {
        if (b == 0) {
            return a;
        } else {
            return gcd(b, a % b);
        }
    }

    public static void main(String[] args) {
        List<Server> serverList = new ArrayList<>();
        serverList.add(new Server("Server1", 4));
        serverList.add(new Server("Server2", 2));
        serverList.add(new Server("Server3", 1));
        WeightedRoundRobin lb = new WeightedRoundRobin(serverList);
        for (int i = 0; i < 10; i++) {
            Server server = lb.nextServer();
            System.out.println("Request " + (i + 1) + " routed to " + server.name);
        }
    }

}

class Server {
    public String name;
    public int weight;

    public Server(String name, int weight) {
        this.name = name;
        this.weight = weight;
    }
}

在此代码示例中，我们首先定义了一个Server类，该类包含服务器的名称和权重。然后我们定义了WeightedRoundRobin类，其中包含服务器列表，当前索引，当前权重，最大权重和最大公约数权重等变量。我们也实现了nextServer()方法，该方法使用加权轮询算法来选择下一个服务器。我们还实现了gcdWeight()和gcd()方法，这些方法用于计算服务器权重的最大公约数。最后，我们在main()方法中创建了一个包含三个服务器的列表，并使用WeightedRoundRobin类来路由请求。