架构师训练营 - 作业 - 第五讲

package class5;
import java.util.ArrayList;
import java.util.List;
public class PhysicalNode {
    /**
     * 物理机名称
     */
    private String name;
    public PhysicalNode(String name){
        this.name = name;
    }
    public String getName() {
        return name;
    }
    /**
     * 命中次数
     */
    private int hitTimes = 0;
    public void hitNode(){
        hitTimes++;
    }
    public int getHitTimes() {
        return hitTimes;
    }
    private List<VirtualNode> virtualNodes = new ArrayList();
    public  void addVirtualNode(VirtualNode virtualNode){
        virtualNodes.add(virtualNode);
        virtualNode.setPhysicalNode(this);
    }
    public List<VirtualNode> getVirtualNodeList(){
        return virtualNodes;
    }
}

package class5;
public class VirtualNode {
    private int hashCode;
    public int getHashCode() {
        return hashCode;
    }
    public VirtualNode(String name) {
        this.hashCode = name.hashCode();
    }
    /**
     * 所属服务器节点
     */
    private PhysicalNode physicalNode;
    public void setPhysicalNode(PhysicalNode physicalNode) {
        this.physicalNode = physicalNode;
    }
    public PhysicalNode getPhysicalNode() {
        return this.physicalNode;
    }
}

package class5;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.UUID;
import java.util.stream.Collectors;
public class ConsistencyHashTest {
    private static int physicalNodeNumber = 10;
    private static int vitualNodeNumberPerPhysicalNode = 200;
    private static int dateNumber = 1000000;
    public static void main(String[] args) {
        List<PhysicalNode> physicalNodeList = new ArrayList<>();
        List<VirtualNode> virtualNodeList = new ArrayList<>();
        //创建服务器节点
        for (int i = 0; i < physicalNodeNumber; i++) {
            PhysicalNode physicalNode = new PhysicalNode("物理机" + i);
            for (int j = 0; j < vitualNodeNumberPerPhysicalNode; j++) {
                VirtualNode virtualNode = new VirtualNode(physicalNode.getName() + "的虚拟节点" + j);
                physicalNode.addVirtualNode(virtualNode);
                virtualNodeList.add(virtualNode);
            }
            physicalNodeList.add(physicalNode);
        }
        //对虚拟节点按照hashcode排序
        virtualNodeList.sort(Comparator.comparing(VirtualNode::getHashCode));
        //生成测试数据
        List<Integer> hashCodeList = new ArrayList<>();
        for (int i = 0; i < dateNumber; i++) {
            int value = UUID.randomUUID().toString().hashCode();
            hashCodeList.add(value);
        }
        //测试命中
        for (int data:hashCodeList) {
            VirtualNode tmpVirtualNode = null;
            for (VirtualNode virtualNode : virtualNodeList) {
                if (virtualNode.getHashCode() >= data) {
                    tmpVirtualNode = virtualNode;
                    virtualNode.getPhysicalNode().hitNode();
                    break;
                }
            }
            if(tmpVirtualNode == null){//未命中数据存入第一个节点
                virtualNodeList.get(0).getPhysicalNode().hitNode();
            }
        }
        //开始统计结果
        int avg = dateNumber/10;
        List<Double> hitList = new ArrayList<>();
        for (PhysicalNode physicalNode:physicalNodeList) {
            System.out.println(physicalNode.getName() + ":" + physicalNode.getHitTimes());
            hitList.add(Double.valueOf(physicalNode.getHitTimes()));
        }
        double dVar=0;
        for(int i=0;i<hitList.size();i++){//求方差
            dVar+=(hitList.get(i)-avg)*(hitList.get(i)-avg);
        }
        System.out.println("标准差：" +Math.sqrt(dVar/10));
        
    }
}

物理机0:141427
物理机1:196323
物理机2:129137
物理机3:217167
物理机4:77759
物理机5:52309
物理机6:22027
物理机7:28890
物理机8:54787
物理机9:80174
标准差：64741.16723692893