java集合线程安全测试

package com.cxy;

import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Created by Administrator on 2017/4/10.
 */
public class CxyDemo {
    // 请求总数
    public static int clientTotal = ;

    // 同时并发执行的线程数
    public static int threadTotal = ;

    //private static Map<Integer, Integer> map = new HashMap<>();
   // private static ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();
    private static Map<Integer, Integer> map = new Hashtable<>();

    public static void main(String[] args) throws Exception {
        //可缓存线程池
        ExecutorService executorService = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadTotal);
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);
        for (int i = ; i < clientTotal; i++) {
            final int count = i;
            //lambda表达式执行任务
            executorService.execute(() -> {
                try {
                    semaphore.acquire();
                    //执行的业务逻辑,可以模仿http请求,发送高并发
                    update(count);
                    semaphore.release();
                } catch (Exception e) {
                    // log.error("exception" , e);
                }
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        executorService.shutdown();
        System.out.println(map.size());
        //log.info("size:{}" , map.size());
    }

    private static void update(int i) {
        //向集合中添加数据
        map.put(i, i);
    }

}

在以上代码中可以运行看出测试:

hahsmap的多次运行结果不一样

concurrentHashmap结果一定是5000,

hashtable也一定是5000,