从一次线上故障说起：Java线程池优化实践与思考

// 查看当前线程池状态
thread -n 10 // 查看最忙碌的10个线程
jstack <pid> // 获取线程堆栈信息

// 问题配置
ThreadPoolExecutor executor = new ThreadPoolExecutor(
    10, // corePoolSize
    20, // maximumPoolSize
    60L, TimeUnit.SECONDS,
    new LinkedBlockingQueue<>(1000) // 过大队列容量
);

// 优化后的配置
ThreadPoolExecutor executor = new ThreadPoolExecutor(
    5, // 核心线程数：日常负载所需
    50, // 最大线程数：峰值流量处理
    30L, TimeUnit.SECONDS, // 空闲线程回收时间
    new ResizableCapacityBlockingQueue<>(200), // 可动态调整的队列
    new NamedThreadFactory("order-processor"), // 自定义线程工厂
    new ThreadPoolExecutor.CallerRunsPolicy() // 饱和策略
);

// 动态线程池配置管理
@RestController
public class ThreadPoolConfigController {
    
    @Autowired
    private BusinessThreadPool businessThreadPool;
    
    @PostMapping("/thread-pool/adjust")
    public ResponseEntity<String> adjustPoolConfig(
            @RequestParam int coreSize,
            @RequestParam int maxSize,
            @RequestParam int queueCapacity) {
        
        businessThreadPool.setCorePoolSize(coreSize);
        businessThreadPool.setMaximumPoolSize(maxSize);
        businessThreadPool.setQueueCapacity(queueCapacity);
        
        return ResponseEntity.ok("线程池配置更新成功");
    }
    
    @GetMapping("/thread-pool/metrics")
    public ThreadPoolMetrics getPoolMetrics() {
        return businessThreadPool.getMetrics();
    }
}

// 线程池指标监控
public class MonitorThreadPoolExecutor extends ThreadPoolExecutor {
    
    @Override
    protected void beforeExecute(Thread t, Runnable r) {
        super.beforeExecute(t, r);
        Metrics.counter("thread.pool.task.start")
               .tag("poolName", poolName)
               .increment();
    }
    
    @Override
    protected void afterExecute(Runnable r, Throwable t) {
        super.afterExecute(r, t);
        Metrics.timer("thread.pool.task.duration")
               .tag("poolName", poolName)
               .record(...);
    }
    
    public ThreadPoolMetrics getMetrics() {
        return new ThreadPoolMetrics(
            getPoolSize(),
            getActiveCount(),
            getCompletedTaskCount(),
            getQueue().size(),
            getQueue().remainingCapacity()
        );
    }
}