Observable Flowable Test-优快云博客

本文通过具体实例，对比了RxJava中Observable与Flowable在不同场景下的性能表现，深入探讨了两者在处理大量数据流时的优劣。实验设计涵盖了从数据生成到处理的全过程，利用不同的调度器和操作符来观察其对执行效率的影响。

package com.test.rxjava;

import java.time.Duration;
import java.time.Instant;
import java.util.LinkedList;
import java.util.concurrent.CountDownLatch;

import org.apache.commons.lang3.time.DurationFormatUtils;

import io.reactivex.Flowable;
import io.reactivex.Observable;
import io.reactivex.ObservableOnSubscribe;
import io.reactivex.schedulers.Schedulers;

public class ObservableTest {
  
  public static void main(String[] args) {
    ObservableTest test = new ObservableTest();
    CountDownLatch latch = new CountDownLatch(1);
    test.run();
    try {
      latch.await();
    } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  private void run() {
    LinkedList<Integer> aList = new LinkedList<Integer>();
    for (int i = 0; i < 10000000; i++) {
      aList.add(i);
    }
    Instant start = Instant.now();
    Observable
    //Flowable
    //.fromIterable(aList)
    .create((ObservableOnSubscribe<Integer>) observableEmitter -> {
      //observableEmitter: 发射器
      Integer i = 0;
      while ( true){
          i++;
          System.out.println(i);
          observableEmitter.onNext(i);
      }
  })
    .observeOn(Schedulers.io())
    .subscribeOn(Schedulers.newThread())
    //.filter(i -> i%2==0)
    .subscribe(this::next, throwable -> throwable.printStackTrace(),()-> System.out.println(DurationFormatUtils.formatDurationWords(Duration.between(start, Instant.now()).toMillis(), true, true)));
  }
  private void next(Integer i) {
    try {
      Thread.sleep(100000);
    } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    System.out.println(Thread.currentThread().getName()+":"+i);
  }
}

package com.test.rxjava;

import java.time.Duration;
import java.time.Instant;
import java.util.Iterator;
import java.util.concurrent.CountDownLatch;

import org.apache.commons.lang3.time.DurationFormatUtils;

import io.reactivex.Flowable;
import io.reactivex.Observable;
import io.reactivex.schedulers.Schedulers;

public class ObservableTest implements Iterable<Integer> {

  private Integer begin;
  private Integer end;

  private ObservableTest(Integer begin, Integer end) {
    this.begin = begin;
    this.end = end;
  }
  
  public static void main(String[] args) {
    ObservableTest test = new ObservableTest(0, 1_000_000);
    CountDownLatch latch = new CountDownLatch(1);
    test.run(test, latch);
    try {
      latch.await();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
  }

  private void run(ObservableTest test, CountDownLatch latch) {
    Instant start = Instant.now();
    //Observable
         Flowable
        .fromIterable(test).observeOn(Schedulers.io()).subscribeOn(Schedulers.newThread())
        .subscribe(this::handleNext, e -> {
          e.printStackTrace();
          latch.countDown();
        }, () -> {
          System.out.println(DurationFormatUtils
              .formatDurationWords(Duration.between(start, Instant.now()).toMillis(), true, true));
          latch.countDown();
        });
  }

  private void handleNext(Integer i) {
    System.out.println("consumer: "+Thread.currentThread().getName() + ":" + i);
  }

  public Iterator<Integer> iterator() {
    return new Itr(begin, end);
  }

  private class Itr implements Iterator<Integer> {
    private Integer begin;
    private Integer end;

    private Itr(Integer begin, Integer end) {
      this.begin = begin;
      this.end = end;
    }

    @Override
    public boolean hasNext() {
      return begin < end;
    }


    @Override
    public Integer next() {
      begin++;
      try {
        Thread.sleep(100);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
      System.out.println("producer: "+Thread.currentThread().getName() + ":" + begin);
      return begin;
    }
  }
}

package com.test.rxjava;

import java.time.Duration;
import java.time.Instant;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CountDownLatch;

import org.apache.commons.lang3.time.DurationFormatUtils;

import io.reactivex.Observable;
import io.reactivex.schedulers.Schedulers;

public class ObservableTest implements Iterable<Integer> {

  private Integer begin;
  private Integer end;

  private ObservableTest(Integer begin, Integer end) {
    this.begin = begin;
    this.end = end;
  }
  
  public static void main(String[] args) {
    ObservableTest test = new ObservableTest(0, 100_000_000);
    CountDownLatch latch = new CountDownLatch(1);
    test.run(test, latch);
    try {
      latch.await();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
  }

  private void run(ObservableTest test, CountDownLatch latch) {
    Instant start = Instant.now();
    Observable
        .fromIterable(test)
        .observeOn(Schedulers.io())
        .subscribeOn(Schedulers.newThread())
        .filter(i -> i%2==0)
        .buffer(1000)
        .subscribe(this::handleNext, e -> {
          e.printStackTrace();
          latch.countDown();
        }, () -> {
          System.out.println("Observable:" + DurationFormatUtils
              .formatDurationWords(Duration.between(start, Instant.now()).toMillis(), true, true));
          latch.countDown();
        });
  }

  private void handleNext(List<Integer> i) {
    System.out.println("consumer: "+Thread.currentThread().getName() + ":" + i.get(i.size()-1));
  }

  public Iterator<Integer> iterator() {
    return new Itr(begin, end);
  }

  private class Itr implements Iterator<Integer> {
    private Integer begin;
    private Integer end;

    private Itr(Integer begin, Integer end) {
      this.begin = begin;
      this.end = end;
    }

    @Override
    public boolean hasNext() {
      return begin < end;
    }


    @Override
    public Integer next() {
      begin++;
      //System.out.println("producer: "+Thread.currentThread().getName() + ":" + begin);
      return begin;
    }
  }
}

package com.test.rxjava;

import java.time.Duration;
import java.time.Instant;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CountDownLatch;

import org.apache.commons.lang3.time.DurationFormatUtils;

import io.reactivex.Flowable;
import io.reactivex.schedulers.Schedulers;

public class FlowableTest implements Iterable<Integer> {

  private Integer begin;
  private Integer end;

  private FlowableTest(Integer begin, Integer end) {
    this.begin = begin;
    this.end = end;
  }
  
  public static void main(String[] args) {
    FlowableTest test = new FlowableTest(0, 100_000_000);
    CountDownLatch latch = new CountDownLatch(1);
    test.run(test, latch);
    try {
      latch.await();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
  }

  private void run(FlowableTest test, CountDownLatch latch) {
    Instant start = Instant.now();
    Flowable
        .fromIterable(test)
        .observeOn(Schedulers.io())
        .subscribeOn(Schedulers.newThread())
        .filter(i -> i%2==0)
        .buffer(1000)
        .subscribe(this::handleNext, e -> {
          e.printStackTrace();
          latch.countDown();
        }, () -> {
          System.out.println("Flowable:" + DurationFormatUtils
              .formatDurationWords(Duration.between(start, Instant.now()).toMillis(), true, true));
          latch.countDown();
        });
  }

  private void handleNext(List<Integer> i) {
    System.out.println("consumer: "+Thread.currentThread().getName() + ":" + i.get(i.size()-1));
  }

  public Iterator<Integer> iterator() {
    return new Itr(begin, end);
  }

  private class Itr implements Iterator<Integer> {
    private Integer begin;
    private Integer end;

    private Itr(Integer begin, Integer end) {
      this.begin = begin;
      this.end = end;
    }

    @Override
    public boolean hasNext() {
      return begin < end;
    }


    @Override
    public Integer next() {
      begin++;
      //System.out.println("producer: "+Thread.currentThread().getName() + ":" + begin);
      return begin;
    }
  }
}