架构师训练营 week5 课后作业

import java.util.ArrayList;import java.util.Collection;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Random;import java.util.SortedMap;import java.util.TreeMap;import java.util.concurrent.ConcurrentHashMap;
public class ConsistentHashingExample {
	// 服务器总数	private static final int SERVERS_NUM = 100;	// 每台服务器需要设置的虚拟节点数	private static final int VIRTUAL_NODES = 10;
	// HASH环	private static SortedMap<Integer, String> treeMapHash;
	// 待加入 Hash 环的服务器列表	private static ArrayList<String> serverList = new ArrayList<>();
	private static void init() {		// 构造服务器数据		for (int i = 0; i < SERVERS_NUM; i++) {			String s = new StringBuilder().append("192.168.0.").append(String.valueOf(i)).toString();			serverList.add(s);		}		// 构建 Hash 环		treeMapHash = buildHash(new TreeMap<Integer, String>());		// 将服务器的虚拟节点添加到 Hash 环中		for (String s : serverList) {			for (int i = 0; i < VIRTUAL_NODES; i++) {				String VNNode = s + "&&VN" + String.valueOf(i);				addServerNode(VNNode);			}		}	}
	// 构建 Hash 环	private static SortedMap<Integer, String> buildHash(TreeMap<Integer, String> treeMap) {		treeMapHash = treeMap;		return treeMapHash;	}
	private static String[] getIPAddress(int num) {		String[] res = new String[num];		Random random = new Random();		for (int i = 0; i < num; i++) {			res[i] = String.valueOf(random.nextInt(256)) + "." + String.valueOf(random.nextInt(256)) + "."					+ String.valueOf(random.nextInt(256)) + "." + String.valueOf(random.nextInt(256)) + ":"					+ String.valueOf(random.nextInt(9999));		}		return res;	}
	private static void addServerNode(String serverNodeName) {		int hash = new GetHashCode().getHashCode(serverNodeName);		treeMapHash.put(hash, serverNodeName);		System.out.println("上线服务器节点：" + serverNodeName);	}
	private static void delServerNode(String serverNodeName) {		int hash = new GetHashCode().getHashCode(serverNodeName);		treeMapHash.remove(hash);		System.out.println("下线服务器节点：" + serverNodeName);	}
	private static String selectServerNode(String requestURL) {		int hash = new GetHashCode().getHashCode(requestURL);		// 向右寻找第一个 key		Map.Entry<Integer, String> subEntry = ((TreeMap<Integer, String>) treeMapHash).ceilingEntry(hash);		// 设置成一个环，如果超过尾部，则取第一个点		subEntry = subEntry == null ? ((TreeMap<Integer, String>) treeMapHash).firstEntry() : subEntry;		String VNNode = subEntry.getValue();		return VNNode.substring(0, VNNode.indexOf("&&"));	}
	public static void main(String[] args) {		init();		// 请求节点		String[] nodes = getIPAddress(100);		// <节点，服务器>		for (int i = 0; i < nodes.length; i++) {			// 选择服务器			String serverIP = selectServerNode(nodes[i]);			System.out.println("请求节点：["+nodes[i] + "]选择的服务器节点是：" + serverIP);		}
	}
}