权重轮询调度算法(WeightedRound-RobinScheduling)-Java实现3

权重轮询调度算法(WeightedRound-RobinScheduling)-Java实现3

以前两篇相关博文：
权重轮询调度算法(WeightedRound-RobinScheduling)-Java实现
http://www.cnblogs.com/huligong1234/p/3819979.html

权重轮询调度算法(WeightedRound-RobinScheduling)-Java实现2
http://www.cnblogs.com/huligong1234/p/3862665.html

以前两篇讲到的方案都稍复杂些，在实际项目中，对权重轮询精确要求不高的状况下，还能够有更简便的方式，就是利用Java自带的Random来实现。
（固然也能够利用Collections.shuffle()来达到目的）
示例代码以下：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
* 权重轮询调度算法(WeightedRound-RobinScheduling)-Java实现
* @author huligong
* */
public class WeightedRoundRobinScheduling {

    public static void main(String[] args) {
        Map<String,Integer> serverWeight = new HashMap<String,Integer>();
        serverWeight.put("192.168.1.100", 6);//ip,权重
        serverWeight.put("192.168.1.101", 3);
        serverWeight.put("192.168.1.102", 2);
        serverWeight.put("192.168.1.104", 1);
        
        String ip = getServer(serverWeight);
    }
    
    public static String getServer(Map<String,Integer> serverWeight){
        Random random = new Random();
        
        ArrayList<String> serverList = new ArrayList<String>();
        for(Map.Entry<String, Integer> m : serverWeight.entrySet()){
            for(int i=0,len=m.getValue();i<len;i++){
                serverList.add(m.getKey());
            }
        }
        
        String[] servers = serverList.toArray(new String[serverList.size()]);
        int weight_idx = random.nextInt(servers.length);
        String ip = servers[weight_idx];
        return ip;
    }

}