在性能优化过程中不可避免的会遇到需要多线程去查询或者处理数据，也就会遇到结果集合并的需求，下面是多线程结果集的示例
package com.yanling.executor;import java.util.ArrayList;
import java.util.Iterator;
import java.util.Random;
import java.util.concurrent.*;public class ExecutorServiceDemo {public static void main(String[] args) {ExecutorServiceDemo.task();}private final static int NUMBER = 3;public static void task() {// 创建线程池。ExecutorService pool = Executors.newFixedThreadPool(NUMBER);ArrayList<Future<String>> futures = new ArrayList<Future<String>>();for (int i = 0; i < 10; i++) {int f = i;// 创建调度任务FutureTask<String> futureTask = new FutureTask<>(() -> {Thread.sleep(new Random().nextInt(10));return ""+f;});// 执行任务pool.execute(futureTask);futures.add(futureTask);}System.out.println("遍历获取结果中...");while(futures.size() > 0) {Iterator<Future<String>> iterator = futures.iterator();while (iterator.hasNext()) {Future<String> future = iterator.next();try {// 判断是否返回结果，防止直接回去结果阻塞if (future.isDone()) {System.out.println(future.get());iterator.remove();}} catch (Exception e) {e.printStackTrace();}}try {// 释放CPU，降低服务器压力Thread.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}}System.out.println("完成遍历结果.");// 关闭线程池。pool.shutdown();}
}