static private final AtomicLong SEQ = new AtomicLong(0);

@RequestMapping(value = "sleep/{s}", method = GET)
public Result<Long> sleepForSeconds(@PathVariable("s") int secondNum)
{
    long index = SEQ.incrementAndGet();
    try { Thread.sleep(secondNum * 1000); }
    catch (InterruptedException iex) { }
    Result<Long> result = new Result<>();
    result.setData(index);
    result.setSuccess(true);
    return result;
}

前端（JavaScript with jQuery）

<div id="area_display"></div>
<script>
var nowInMillis = new Date().getTime();
for (var i = -1; ++i != 28; )
{
    $.get(apictx + ‘/try/sleep/4?t=‘ + nowInMillis + ‘_‘ + i).done(function(result)
    {
        var html = $(‘#area_display‘).html();
        html += result.data + ‘(use ‘;
        html += new Date().getTime() - nowInMillis + ‘ms)<br />‘;
        $(‘#area_display‘).html(html);
    });
}
</script>

本文还发表于在其它网站
CSDN ：https://blog.csdn.net/ShaneLooLi/article/details/104123946
ITeye ：https://www.iteye.com/blog/user/surmounting/blog/2512203
中国开源社区：https://my.oschina.net/shane1984/blog/3162224

通过实验，整理了部分主流手机浏览器的并发请求数