JAVA线程池优化

最新推荐文章于 2025-10-06 06:02:45 发布

原创最新推荐文章于 2025-10-06 06:02:45 发布 · 541 阅读

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#java

本文探讨了在高并发环境下优化线程池的方法，通过调整核心线程数、最大线程数等参数，结合阻塞队列和任务拒绝策略，提升系统处理能力。实测案例展示了线程池在高负载下的表现。

前言：随着信息技术的进步，各行各业对数据价值的重视程度急剧上升，越来越多的数据被分门别类地积聚下来，对数据库的并发要求越来越高，即同一时间点的数据请求越来越多，对实时性的要求也越来越高。实时性其实是不经过批量排队的高并发实时请求的代名词，同一时间的请求量和请求的处理速度直接决定了并发度：

1.优化的代码

//参数初始化
private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
 //获取cpu核心数：
private static final int getCpuCount = Runtime.getRuntime().availableProcessors();
//核心线程数量大小
private static final int corePoolSize = Math.max(2, Math.min(CPU_COUNT - 1, 4));
//线程池最大容纳线程数
private static final int maximumPoolSize = CPU_COUNT * 2 + 1;
//线程空闲后的存活时长
private static final int keepAliveTime = 30;
 
//任务过多后，存储任务的一个阻塞队列
BlockingQueue<Runnable>  workQueue = new SynchronousQueue<>();
 
//线程的创建工厂
ThreadFactory threadFactory = new ThreadFactory() {
    private final AtomicInteger mCount = new AtomicInteger(1);
 
    public Thread newThread(Runnable r) {
        return new Thread(r, "AdvacnedAsyncTask #" + mCount.getAndIncrement());
    }
};
 
//线程池任务满载后采取的任务拒绝策略
RejectedExecutionHandler rejectHandler = new ThreadPoolExecutor.DiscardOldestPolicy();
 
//线程池对象，创建线程
ThreadPoolExecutor mExecute = new ThreadPoolExecutor(
        corePoolSize, 
        maximumPoolSize,
        keepAliveTime,
        TimeUnit.SECONDS,
        workQueue,
        threadFactory, 
        rejectHandler
);

2.具体实现：

@Test
    public  void test2() throws InterruptedException {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss.SSS");
        // 有界队列
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(5);
        // 放弃拒绝的任务并抛出异常
        RejectedExecutionHandler abortPolicyHandler = new ThreadPoolExecutor.AbortPolicy();
        RejectedExecutionHandler discardPolicyHandler = new ThreadPoolExecutor.DiscardPolicy();
        ThreadPoolExecutor threadPool =
                new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, TimeUnit.SECONDS, workQueue, discardPolicyHandler);
        long start = System.currentTimeMillis();
        System.out.println("开始时间："+formatter.format(new Date()));
        for (int i = 0; i < 10000; i++) {
            sta(i);
        }
        System.out.println("队列任务数" + threadPool.getQueue().size());
        System.out.println("线程池数" + threadPool.getPoolSize());
        System.out.println("cpu核数:"+corePoolSize);
        System.out.println("核心线程数量大小:"+getCpuCount);
        System.out.println("线程池最大容纳线程数:"+maximumPoolSize);
        System.out.println("结束时间："+formatter.format(new Date()));
    }
    public  void sta(int i){
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss.SSS");
        System.out.println(formatter.format(new Date()) + ": Thread ID :" + Thread.currentThread().getId()+"名字："+Thread.currentThread().getName()+i);
    }