MapReduce模型（对数据的统计分析)_使用mapreduce统计数量占比

1.编写一个简单的数据统计操作

package 集合框架库.Map集合.MapReduce;
public class Order {
    private  String title;
    private  double price;
    private  int amonu;
    public Order(String title, double price, int amonu) {
        this.title = title;
        this.price = price;
        this.amonu = amonu;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public int getAmonu() {
        return amonu;
    }
    public void setAmonu(int amonu) {
        this.amonu = amonu;
    }
    @Override
    public String toString() {
        return "Order{" +
                "title='" + title + '\'' +
                ", price=" + price +
                ", amonu=" + amonu +
                '}';
    }
}

2.测试 

package 集合框架库.Map集合.MapReduce;
import java.util.ArrayList;
import java.util.DoubleSummaryStatistics;
import java.util.List;
public class TestMapReduce {
    public static void main(String[] args) {
        List<Order> orderList =new ArrayList <> ( );
        orderList.add ( new Order ( "Iphone",899.45,22 ) );
        orderList.add(new Order("外星人",1897.77,45));
        orderList.add ( new Order ( "MacBookPro",1899.96,14 ) );
        orderList.add ( new Order ( "Java学习宝典",7888.9,56 ) );
double TotalPrice=orderList.stream ().map ( order -> order.getPrice ()*order.getAmonu ()).reduce ( (sum,x )->sum+x ).get ();
        System.out.println ("所花的总数额为："+TotalPrice );
        DoubleSummaryStatistics dss=orderList.stream ().mapToDouble ( order->order.getPrice ()*order.getAmonu () ).summaryStatistics ();
        System.out.println ("总量："+dss.getCount () );
        System.out.println ("平均值"+dss.getAverage () );
        System.out.println ("最大值："+dss.getMax () );
        System.out.println ("最小值："+dss.getMin () );
        System.out.println ("总和:"+dss.getSum () );
    }
}

3.运行结果