用java8流映射reduce

对于类分配，我必须使用Java8流来模拟MapReduce，但要让它运行起来有很多困难。有人能帮我完成第一步的映射吗？到目前为止，我得到的代码都是她的： WeatherStationsQ2.java

package assignmnent2;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class WeatherStationQ2 {

    //Setting up class attributes
    private String city;
    private List<MeasurementQ2> measurements;
    public static List<WeatherStationQ2> stations= new ArrayList<>();


    //Setting up constructor for the WeatherStationQ1 object
    public WeatherStationQ2(String city, List<MeasurementQ2> measurements/*,List<String> stations*/){
        this.city = city;
        this.measurements = measurements;
    }

    //Setting up the setters and getters for the attributes of the object WeatherStationQ1
    public void setCity(String city){
        this.city = city;
    }

    public String getCity(){
        return city;        
    }

    public void setMeasurements(List<MeasurementQ2> measurements){
        this.measurements = measurements;
    }

    public List<MeasurementQ2> getMeasurements(){
        return measurements;
    }

    //MaxTemperature function to return highest temperature of a given time range
    public void maxTemperature(int startTime, int endTime){

        //Creates a list of the MeasurementQ2 object in the selected time range
        List<MeasurementQ2> tempList = this.getMeasurements().stream().filter(e -> e.getTime()>=startTime)
                .filter(e -> e.getTime()<=endTime).collect(Collectors.toList());

        //Finding the MeasurementQ2 with the higher temperature in the filtered list
        MeasurementQ2 maxMe = tempList.stream().max(Comparator.comparing(MeasurementQ2::getTemperature))
                  .orElseThrow(NoSuchElementException::new);

        //Display results
        System.out.println("The maximum temperature was: "+maxMe.getTemperature()+" and it happen at time: "+maxMe.getTime());
    }

    public static void countTemperature(double t1, double t2, int r){
        Stream<List<WeatherStationQ2>> st = Arrays.asList(stations).stream();
        Map<Integer, Double> map = st
        //List <MeasurementQ2> map =  (List<MeasurementQ2>) stations.parallelStream().map(WeatherStationQ2::getMeasurements);
        //Map <Integer, Double> map = stations.parallelStream().collect(Collectors.groupingBy(MeasurementQ2::getTime, MeasurementQ2::getTemperature));
        /*Stream<List<WeatherStationQ2>> st  = Arrays.asList(stations).stream();
        Stream<List<WeatherStationQ2>> map = st.map(s -> s);*/

        st.forEach(s->System.out.println(s));
    }

    public static void main(String Args[]){
        //Creates a series of MeasurementQ1 object, creates a list and populate the list
        MeasurementQ2 m = new MeasurementQ2(1, 2.0);
        MeasurementQ2 n = new MeasurementQ2(13, 8.1);
        MeasurementQ2 o = new MeasurementQ2(25, 12.5);
        List<MeasurementQ2> mesearements = new ArrayList<>();
        mesearements.add(m);
        mesearements.add(n);
        mesearements.add(o);
        MeasurementQ2 p = new MeasurementQ2(3, 23.6);
        MeasurementQ2 q = new MeasurementQ2(11, 13.8);
        MeasurementQ2 r = new MeasurementQ2(28, 14.5);
        List<MeasurementQ2> measure = new ArrayList<>();
        measure.add(p);
        measure.add(q);
        measure.add(r);

        //Creates the WeatherStationQ1 object
        WeatherStationQ2 WS = new WeatherStationQ2("Galway", mesearements);
        WeatherStationQ2 WS2 = new WeatherStationQ2("Dublin", measure);

        stations.add(WS);
        stations.add(WS2);
        WS.maxTemperature(1, 30);// Applying the maxTemperature method
        WS2.maxTemperature(1, 30);

        countTemperature(19.0,10.8,3);
    }
}

任务描述： 问题1[40分] 创建一个 具有三个属性字段的类别气象站：气象站所在的城市、气象站的测量值和类别测量对象列表，以及静态字段气象站和所有现有气象站列表。还要创建一个类度量。类度量对象的属性时间应为整数，温度应为双倍数。将maxTemperaturestartTime、endTime方法添加到此类，该类返回气象站在startTime和endTime之间测量的最高温度。 这部分完成了

问题2[60分] 将上一个问题中的CountTemperatures1、t2、r方法添加到类WeatherStation中。该方法应返回一个包含两对的列表：1个温度t1与区间[t1-r..t1+r]内任何气象站迄今为止测量的温度次数配对，2个温度t2与区间[t2-r..t2+r]内温度次数配对迄今为止，气象站中的任何一个气象站都已对其进行了测量。 为了计算结果，您需要使用“模拟的”MapReduce方法。也就是说，您的代码应该类似于MapReduce方法，但只使用Java>=8，没有机器集群，也没有任何MapReduce软件框架。此外，您需要尽可能使用Java8流，并在适当的情况下使用并行流处理。 最后，在main方法中添加代码，该方法使用几个测试站和 一些测试测量数据，并打印结果

---

问题1已完成，但我无意中发现了问题2

您可以对所有电台使用下面的片段来获得计数

    long count = this.getMeasurements()
        .stream()
        .filter(e -> Math.abs(e.getTime() - t1) <= r)
        .count();

这是输出：

The maximum temperature was: 12.5 and it happen at time: 25
The maximum temperature was: 23.6 and it happen at time: 3
2
1

---

有太多的文字，没有人会读它，请给一个最低限度的帖子你应该让你的问题更简洁。太多的文本我现在编辑了问题你只是复制粘贴你的作业。嗯@AlexAcquier，上面的代码片段很有效。请参阅我编辑的回复以获取完整的代码。虽然没有完全满足我的需要，但方向是正确的，谢谢@mayurmadnani

public static void countTemperature(double t1, double t2, int r) {
    stations.stream()
            .map(station ->
                    station.getMeasurements()
                            .stream()
                            .filter(e -> Math.abs(e.getTime() - t1) <= r)
                            .count()
            )
            .forEach(System.out::println);
}

countTemperature(19.0, 10.8, 8);

The maximum temperature was: 12.5 and it happen at time: 25
The maximum temperature was: 23.6 and it happen at time: 3
2
1