关于spring:底层到底做了什么-从spring-的Async-看AOP调用过程

上文曾经讲过@EnableAsync的bean构建过程，这里持续合成@Async执行过程，以及spring 的AOP调用过程。

先上demo

public class ApiGatewayApplication {  public static void main(String[] args) {    SpringApplication.run(ApiGatewayApplication.class, args);    AsyncTest test = BeanUtils.getBean("asyncTest");    test.test();//1  }}@Configurationpublic class WorkPool {    @Bean("WorkPool")    public ThreadPoolTaskExecutor  taskExecutor(){        ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();        threadPoolTaskExecutor.initialize();        return threadPoolTaskExecutor;    }}@Componentpublic class AsyncTest {    @Async    public void test() {        System.out.printf("test");     }}

1、这一步是上面的重点，底层是怎么调用。

    private static class DynamicAdvisedInterceptor implements MethodInterceptor, Serializable {        @Nullable        public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);                Object retVal;                if (chain.isEmpty() && Modifier.isPublic(method.getModifiers())) {                    Object[] argsToUse = AopProxyUtils.adaptArgumentsIfNecessary(method, args);                    retVal = methodProxy.invoke(target, argsToUse);//2                } else {                    retVal = (new CglibAopProxy.CglibMethodInvocation(proxy, target, method, args, targetClass, chain, methodProxy)).proceed();//3                } }

2、如果没有AOP行为，间接调用原bean。
3、如果有AOP行为，结构一个 Cglib的CglibMethodInvocation 办法回调对象。

public class ReflectiveMethodInvocation implements ProxyMethodInvocation, Cloneable { public Object proceed() throws Throwable {                    Object interceptorOrInterceptionAdvice = this.interceptorsAndDynamicMethodMatchers.get(++this.currentInterceptorIndex);            if (interceptorOrInterceptionAdvice instanceof InterceptorAndDynamicMethodMatcher) {                InterceptorAndDynamicMethodMatcher dm = (InterceptorAndDynamicMethodMatcher)interceptorOrInterceptionAdvice;                Class<?> targetClass = this.targetClass != null ? this.targetClass : this.method.getDeclaringClass();                return dm.methodMatcher.matches(this.method, targetClass, this.arguments) ? dm.interceptor.invoke(this) : this.proceed();            } else {                return ((MethodInterceptor)interceptorOrInterceptionAdvice).invoke(this);//4            }        }    }

4、找到AsyncExecutionInterceptor执行器

public class AsyncExecutionInterceptor extends AsyncExecutionAspectSupport implements MethodInterceptor, Ordered { @Nullable    public Object invoke(MethodInvocation invocation) throws Throwable { return this.doSubmit(task, executor, invocation.getMethod().getReturnType());//4 } public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport implements AsyncListenableTaskExecutor, SchedulingTaskExecutor {public <T> Future<T> submit(Callable<T> task) { //5        ThreadPoolExecutor executor = this.getThreadPoolExecutor();        try {            return executor.submit(task);        } catch (RejectedExecutionException var4) {            throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, var4);        }    } }

4、通过doSubmit将工作发给TaskExecutor，实现Async异步的性能。
5、ThreadPoolTaskExecutor就是在demo中定义的WorkPool。

最终实现Asyn异步调用。