package com.basic;

import java.util.Arrays;

import java.util.Hashtable;

import java.util.Map;

import java.util.Random;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.CountDownLatch;

/**

* @program JavaBooks

* @description: ConcurrentMap

* @author: mf

* @create: 2019/12/31 19:59

*/

public class T20 {

public static void main(String[] args) {

// Map<String, String> map = new Hashtable<>();

Map<String, String> map = new ConcurrentHashMap<>();

Random r = new Random();

Thread[] ths = new Thread[100]; // 100个线程

CountDownLatch latch = new CountDownLatch(ths.length);

long start = System.currentTimeMillis();

for (int i = 0; i < ths.length; i++) {

ths[i] = new Thread(() -> {

for (int i1 = 0; i1 < 10000; i1++) {

map.put("a" + r.nextInt(100000), "a" + r.nextInt(100000));

}

latch.countDown();

});

}

Arrays.asList(ths).forEach(t -> t.start());

try {

latch.await();

} catch (InterruptedException e) {

e.printStackTrace();

}

long end = System.currentTimeMillis();

System.out.println(end -start);

}

}