利用多线程+countDownluanch 优化查询接口提升效率10倍以上

最近在做工单系统的生产调优，客户想要单子秒出

花了一天时间定位问题，发现查询MySQL、Mongo、Redis 查询耗时都很小，在0～4ms

耗时较大的是一段给 activity 中 form 的 field 设置属性的遍历

有一段 activities.forEach(activity -> {})，循环中有两个嵌套，一个两层，一个三层，逻辑上不好拆分

于是采用多线程+countdownlaunch，把每次循环通过线程发出去，原有逻辑放到 Runnable 的 run 方法中

countdownlaunch卡住主线程，等待所有并行线程执行完毕

大大降低消耗时间，测试工单查询调用该方法的耗时由原先的 1.2s 降低至 120ms

CountDownLatch countDownLatch = new CountDownLatch(activities.size());

activities.forEach(activity -> {
    AssembleForm assembleForm = new AssembleForm(activity, forms, fields, countDownLatch);
    Thread thread = new Thread(assembleForm);
    thread.start();
});
try {
    countDownLatch.await();
} catch (InterruptedException e) {
    log.error("countDownLaunch error: {}", e.getMessage());
}

public class AssembleForm implements Runnable{

    private List<Form> forms;
    private List<Field> fields;
    private Activity activity;
    private CountDownLatch countDownLatch;


    AssembleForm(Activity activity, List<Form> forms, List<Field> fields, CountDownLatch countDownLatch){
        this.activity = activity;
        this.forms = forms;
        this.fields = fields;
        this.countDownLatch = countDownLatch;
    }

    @Override
    public void run() {
        // 原有逻辑
        codes...
        countDownLatch.countDown();
    }
}