标签：rom invoke catch simple exec odi spring deb 控制
在ConcurrencyThrottleSupport类中，简单的通过synchronized和wati and notify达到控制线程数量的效果，从而实现限流的策略。
一、类图
二、主要方法
先看ConcurrencyThrottleInterceptor.java类的源码：
看该拦截器中的invoke()方法中，在执行目标方法的前后分别执行beforeAccess()和 afterAccess()方法，
public class ConcurrencyThrottleInterceptor extends ConcurrencyThrottleSupport implements MethodInterceptor, Serializable { public ConcurrencyThrottleInterceptor() { setConcurrencyLimit(1); } @Override public Object invoke(MethodInvocation methodInvocation) throws Throwable { beforeAccess(); try { return methodInvocation.proceed(); } finally { afterAccess(); } } }
beforeAccess()实现（在父类ConcurrencyThrottleSupport中实现）
protected void beforeAccess() { if (this.concurrencyLimit == NO_CONCURRENCY) { throw new IllegalStateException( "Currently no invocations allowed - concurrency limit set to NO_CONCURRENCY"); } if (this.concurrencyLimit > 0) { boolean debug = logger.isDebugEnabled(); synchronized (this.monitor) { boolean interrupted = false; while (this.concurrencyCount >= this.concurrencyLimit) { if (interrupted) { throw new IllegalStateException("Thread was interrupted while waiting for invocation access, " + "but concurrency limit still does not allow for entering"); } if (debug) { logger.debug("Concurrency count " + this.concurrencyCount + " has reached limit " + this.concurrencyLimit + " - blocking"); } try { this.monitor.wait(); } catch (InterruptedException ex) { // Re-interrupt current thread, to allow other threads to react. Thread.currentThread().interrupt(); interrupted = true; } } if (debug) { logger.debug("Entering throttle at concurrency count " + this.concurrencyCount); } this.concurrencyCount++; } } }
beforeAccess()实现（在父类ConcurrencyThrottleSupport中实现）
protected void afterAccess() { if (this.concurrencyLimit >= 0) { synchronized (this.monitor) { this.concurrencyCount--; if (logger.isDebugEnabled()) { logger.debug("Returning from throttle at concurrency count " + this.concurrencyCount); } this.monitor.notify(); } } }
使用场景见《spring异步线程池-SimpleAsyncTaskExecutor》
spring控制并发数的工具类ConcurrencyThrottleSupport和ConcurrencyThrottleInterceptor
标签：rom invoke catch simple exec odi spring deb 控制
原文地址：https://www.cnblogs.com/duanxz/p/9435873.html
