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生产级别线程池最佳实践

news 2025/10/1 4:42:37

生产环境中使用线程池需要综合考虑资源管理、任务处理、错误恢复和监控等多个方面。以下是生产级别线程池的全面使用指南：

一、线程池创建最佳实践

1. 避免使用Executors快捷方法

// 反模式 - 可能导致OOM
ExecutorService unsafe = Executors.newCachedThreadPool(); // 无界线程池
ExecutorService unsafe2 = Executors.newFixedThreadPool(10); // 无界队列// 正确方式 - 手动创建ThreadPoolExecutor
int corePoolSize = Runtime.getRuntime().availableProcessors();
int maxPoolSize = corePoolSize * 2;
BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(100); // 有界队列
RejectedExecutionHandler handler = new CustomRejectionPolicy();ExecutorService executor = new ThreadPoolExecutor(corePoolSize,maxPoolSize,60L, TimeUnit.SECONDS,workQueue,new CustomThreadFactory("app-worker-"),handler
);

2. 关键配置参数

corePoolSize：常驻核心线程数（根据业务类型调整）
maximumPoolSize：最大线程数（建议不超过100）
keepAliveTime：空闲线程存活时间（30-120秒）
workQueue：必须使用有界队列（避免OOM）
threadFactory：自定义线程工厂
rejectedExecutionHandler：自定义拒绝策略

二、线程池关键组件实现

1. 自定义线程工厂（命名、异常处理）

public class CustomThreadFactory implements ThreadFactory {private final AtomicInteger counter = new AtomicInteger(0);private final String namePrefix;private final ThreadGroup group;public CustomThreadFactory(String namePrefix) {this.namePrefix = namePrefix;SecurityManager s = System.getSecurityManager();this.group = (s != null) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup();}@Overridepublic Thread newThread(Runnable r) {Thread thread = new Thread(group, r, namePrefix + counter.incrementAndGet(), 0);thread.setDaemon(false);thread.setPriority(Thread.NORM_PRIORITY);// 设置未捕获异常处理器thread.setUncaughtExceptionHandler((t, e) -> {logger.error("Uncaught exception in thread: " + t.getName(), e);// 发送告警通知AlertManager.notify(e);});return thread;}
}

2. 自定义拒绝策略（生产级）

public class CustomRejectionPolicy implements RejectedExecutionHandler {@Overridepublic void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {if (!executor.isShutdown()) {// 1. 记录被拒绝任务logger.warn("Task rejected: " + r.toString());// 2. 尝试重新放入队列（带超时）try {boolean offered = executor.getQueue().offer(r, 1, TimeUnit.SECONDS);if (!offered) {// 3. 持久化到存储系统persistTask(r);logger.info("Task persisted to storage: " + r);}} catch (InterruptedException e) {Thread.currentThread().interrupt();logger.error("Re-enqueue interrupted", e);}}}private void persistTask(Runnable task) {// 实现任务持久化逻辑（数据库、文件、消息队列）TaskStorage.save(task);}
}

三、任务提交与执行最佳实践

1. 任务封装（带监控）

public class MonitoredTask implements Runnable {private final Runnable actualTask;private final long submitTime;public MonitoredTask(Runnable task) {this.actualTask = task;this.submitTime = System.currentTimeMillis();}@Overridepublic void run() {long start = System.currentTimeMillis();try {// 设置MDC上下文（日志链路跟踪）MDC.put("traceId", UUID.randomUUID().toString());actualTask.run();long duration = System.currentTimeMillis() - start;Metrics.recordSuccess(duration);} catch (Exception e) {long duration = System.currentTimeMillis() - start;Metrics.recordFailure(duration);// 重试逻辑if (shouldRetry(e)) {retryTask();} else {logger.error("Task execution failed", e);}} finally {MDC.clear();}}// 提交任务时使用public static void submit(ExecutorService executor, Runnable task) {executor.execute(new MonitoredTask(task));}
}

2. 任务超时控制

Future<?> future = executor.submit(task);try {// 设置任务超时时间future.get(30, TimeUnit.SECONDS);
} catch (TimeoutException e) {// 1. 取消任务执行future.cancel(true);// 2. 记录超时日志logger.warn("Task timed out: " + task);// 3. 执行降级策略fallbackHandler.handle(task);
} catch (Exception e) {// 处理其他异常
}

四、线程池监控与管理

1. 监控指标采集

public class ThreadPoolMonitor implements Runnable {private final ThreadPoolExecutor executor;public ThreadPoolMonitor(ThreadPoolExecutor executor) {this.executor = executor;}@Overridepublic void run() {while (!Thread.currentThread().isInterrupted()) {try {// 采集关键指标int activeCount = executor.getActiveCount();long completedTaskCount = executor.getCompletedTaskCount();int queueSize = executor.getQueue().size();int poolSize = executor.getPoolSize();// 发布到监控系统Metrics.gauge("threadpool.active.count", activeCount);Metrics.gauge("threadpool.queue.size", queueSize);Metrics.counter("threadpool.completed.tasks", completedTaskCount);// 检测潜在问题if (queueSize > executor.getQueue().remainingCapacity() * 0.8) {logger.warn("Thread pool queue is approaching capacity");}// 30秒采集一次Thread.sleep(30_000);} catch (InterruptedException e) {Thread.currentThread().interrupt();}}}
}

2. 动态调整线程池参数

public class DynamicThreadPool extends ThreadPoolExecutor {public DynamicThreadPool(int corePoolSize, int maxPoolSize, long keepAliveTime, TimeUnit unit,BlockingQueue<Runnable> workQueue) {super(corePoolSize, maxPoolSize, keepAliveTime, unit, workQueue);}// 动态修改核心线程数public void setCorePoolSize(int corePoolSize) {if (corePoolSize >= 0) {super.setCorePoolSize(corePoolSize);Metrics.gauge("threadpool.core.size", corePoolSize);}}// 动态修改最大线程数public void setMaxPoolSize(int maxPoolSize) {if (maxPoolSize > 0 && maxPoolSize >= getCorePoolSize()) {super.setMaximumPoolSize(maxPoolSize);Metrics.gauge("threadpool.max.size", maxPoolSize);}}// 动态修改队列容量（需要特殊处理）public void resizeQueue(int newCapacity) {BlockingQueue<Runnable> newQueue = new ArrayBlockingQueue<>(newCapacity);BlockingQueue<Runnable> oldQueue = getQueue();// 转移任务synchronized (this) {List<Runnable> transferList = new ArrayList<>();oldQueue.drainTo(transferList);newQueue.addAll(transferList);// 更新队列super.setRejectedExecutionHandler(getRejectedExecutionHandler());super.setQueue(newQueue);}}
}

五、优雅关闭与资源清理

1. 应用关闭时处理

@PreDestroy
public void shutdownExecutor() {// 1. 禁止新任务提交executor.shutdown();try {// 2. 等待现有任务完成if (!executor.awaitTermination(60, TimeUnit.SECONDS)) {// 3. 取消所有未开始任务executor.shutdownNow();// 4. 再次等待任务响应取消if (!executor.awaitTermination(60, TimeUnit.SECONDS)) {logger.error("Thread pool did not terminate");}}} catch (InterruptedException e) {// 5. 中断当前线程并尝试取消executor.shutdownNow();Thread.currentThread().interrupt();}// 6. 清理资源cleanupResources();
}

2. 未完成任务恢复

public void recoverPendingTasks() {BlockingQueue<Runnable> pendingQueue = executor.getQueue();List<Runnable> pendingTasks = new ArrayList<>();pendingQueue.drainTo(pendingTasks);for (Runnable task : pendingTasks) {if (task instanceof RecoverableTask) {// 持久化到可靠存储TaskStorage.save((RecoverableTask) task);logger.info("Recovered pending task: " + task);}}
}

六、生产环境建议

线程隔离策略：
- CPU密集型任务：独立线程池
- I/O密集型任务：独立线程池
- 关键业务：独立线程池（避免相互影响）

资源限制：

// 使用Semaphore控制并发资源使用
private final Semaphore concurrencySemaphore = new Semaphore(50);executor.execute(() -> {try {concurrencySemaphore.acquire();// 执行受限资源操作} finally {concurrencySemaphore.release();}
});

上下文传递：

// 使用TransmittableThreadLocal传递上下文
TransmittableThreadLocal<String> context = new TransmittableThreadLocal<>();executor.execute(TtlRunnable.get(() -> {// 可以访问父线程的context值String value = context.get();
}));

熔断降级：

CircuitBreaker circuitBreaker = new CircuitBreaker();executor.execute(() -> {if (circuitBreaker.allowExecution()) {try {// 执行业务逻辑} catch (Exception e) {circuitBreaker.recordFailure();}} else {// 执行降级逻辑fallbackService.executeFallback();}
});

七、常见问题处理方案

问题	现象	解决方案
线程泄露	线程数持续增长	1. 检查线程是否正常结束 2. 添加线程创建监控 3. 限制最大线程数
任务堆积	队列持续增长	1. 增加消费者线程 2. 优化任务处理速度 3. 实施任务降级
CPU使用率高	CPU持续满载	1. 分析线程栈（jstack） 2. 优化热点代码 3. 限制线程池大小
任务饿死	低优先级任务长期得不到执行	1. 使用优先级队列 2. 拆分不同优先级线程池 3. 实现公平调度
上下文丢失	子线程无法获取上下文	1. 使用TransmittableThreadLocal 2. 手动传递上下文 3. 使用MDC框架