Spring 5.x Source trip forty-eight AOP proxy Details of the three JdkDynamicAopProxy and CglibAopProxy

JdkDynamicAopProxy的getProxy

Mainly JdkDynamicAopProxythere are some things to say at the former Acting:

AopProxyUtils的completeProxiedInterfaces

Here it means increasing the number of other interfaces SpringProxy, DecoratingProxy, Advised.

static Class<?>[] completeProxiedInterfaces(AdvisedSupport advised, boolean decoratingProxy) {
		Class<?>[] specifiedInterfaces = advised.getProxiedInterfaces();
		if (specifiedInterfaces.length == 0) {
			// No user-specified interfaces: check whether target class is an interface.
			Class<?> targetClass = advised.getTargetClass();
			if (targetClass != null) {
				if (targetClass.isInterface()) {
					advised.setInterfaces(targetClass);
				}
				else if (Proxy.isProxyClass(targetClass)) {
					advised.setInterfaces(targetClass.getInterfaces());
				}
				specifiedInterfaces = advised.getProxiedInterfaces();
			}
		}
		boolean addSpringProxy = !advised.isInterfaceProxied(SpringProxy.class);
		boolean addAdvised = !advised.isOpaque() && !advised.isInterfaceProxied(Advised.class);
		boolean addDecoratingProxy = (decoratingProxy && !advised.isInterfaceProxied(DecoratingProxy.class));
		int nonUserIfcCount = 0;
		if (addSpringProxy) {//需要添加SpringProxy接口
			nonUserIfcCount++;
		}
		if (addAdvised) {//需要添加通知
			nonUserIfcCount++;
		}
		if (addDecoratingProxy) {//需要添加DecoratingProxy接口
			nonUserIfcCount++;
		}
		Class<?>[] proxiedInterfaces = new Class<?>[specifiedInterfaces.length + nonUserIfcCount];
		System.arraycopy(specifiedInterfaces, 0, proxiedInterfaces, 0, specifiedInterfaces.length);
		int index = specifiedInterfaces.length;
		if (addSpringProxy) {
			proxiedInterfaces[index] = SpringProxy.class;
			index++;
		}
		if (addAdvised) {
			proxiedInterfaces[index] = Advised.class;
			index++;
		}
		if (addDecoratingProxy) {
			proxiedInterfaces[index] = DecoratingProxy.class;
		}
		return proxiedInterfaces;
	}

CglibAopProxy的getProxy

It is the CGLIBbasic usage, create booster, interceptors, set the parent class, etc.

@Override
	public Object getProxy(@Nullable ClassLoader classLoader) {
		if (logger.isTraceEnabled()) {
			logger.trace("Creating CGLIB proxy: " + this.advised.getTargetSource());
		}

		try {
			Class<?> rootClass = this.advised.getTargetClass();
			Assert.state(rootClass != null, "Target class must be available for creating a CGLIB proxy");

			Class<?> proxySuperClass = rootClass;
			if (rootClass.getName().contains(ClassUtils.CGLIB_CLASS_SEPARATOR)) {//类名是否包含CGLIB分隔符
				proxySuperClass = rootClass.getSuperclass();
				Class<?>[] additionalInterfaces = rootClass.getInterfaces();//获得原始父类的接口
				for (Class<?> additionalInterface : additionalInterfaces) {
					this.advised.addInterface(additionalInterface);
				}
			}
			//验证修饰符和方法修饰符
			// Validate the class, writing log messages as necessary.
			validateClassIfNecessary(proxySuperClass, classLoader);

			// Configure CGLIB Enhancer...
			Enhancer enhancer = createEnhancer();//增强器
			if (classLoader != null) {
				enhancer.setClassLoader(classLoader);
				if (classLoader instanceof SmartClassLoader &&
						((SmartClassLoader) classLoader).isClassReloadable(proxySuperClass)) {
					enhancer.setUseCache(false);
				}
			}
			enhancer.setSuperclass(proxySuperClass);//父类
			enhancer.setInterfaces(AopProxyUtils.completeProxiedInterfaces(this.advised));
			enhancer.setNamingPolicy(SpringNamingPolicy.INSTANCE);
			enhancer.setStrategy(new ClassLoaderAwareGeneratorStrategy(classLoader));

			Callback[] callbacks = getCallbacks(rootClass);
			Class<?>[] types = new Class<?>[callbacks.length];
			for (int x = 0; x < types.length; x++) {
				types[x] = callbacks[x].getClass();
			}
			// fixedInterceptorMap only populated at this point, after getCallbacks call above
			enhancer.setCallbackFilter(new ProxyCallbackFilter(
					this.advised.getConfigurationOnlyCopy(), this.fixedInterceptorMap, this.fixedInterceptorOffset));
			enhancer.setCallbackTypes(types);

			// Generate the proxy class and create a proxy instance.
			return createProxyClassAndInstance(enhancer, callbacks);
		}
		catch (CodeGenerationException | IllegalArgumentException ex) {
			throw new AopConfigException("Could not generate CGLIB subclass of " + this.advised.getTargetClass() +
					": Common causes of this problem include using a final class or a non-visible class",
					ex);
		}
		catch (Throwable ex) {
			// TargetSource.getTarget() failed
			throw new AopConfigException("Unexpected AOP exception", ex);
		}
	}

ObjenesisCglibAopProxy的createProxyClassAndInstance

Generate the proxy class, and then objenesisgenerate an instance.

@Override
	protected Object createProxyClassAndInstance(Enhancer enhancer, Callback[] callbacks) {
		Class<?> proxyClass = enhancer.createClass();
		Object proxyInstance = null;

		if (objenesis.isWorthTrying()) {
			try {
				proxyInstance = objenesis.newInstance(proxyClass, enhancer.getUseCache());
			}
			catch (Throwable ex) {
				logger.debug("Unable to instantiate proxy using Objenesis, " +
						"falling back to regular proxy construction", ex);
			}
		}

		if (proxyInstance == null) {
			// Regular instantiation via default constructor...
			try {
				Constructor<?> ctor = (this.constructorArgs != null ?
						proxyClass.getDeclaredConstructor(this.constructorArgTypes) :
						proxyClass.getDeclaredConstructor());
				ReflectionUtils.makeAccessible(ctor);
				proxyInstance = (this.constructorArgs != null ?
						ctor.newInstance(this.constructorArgs) : ctor.newInstance());
			}
			catch (Throwable ex) {
				throw new AopConfigException("Unable to instantiate proxy using Objenesis, " +
						"and regular proxy instantiation via default constructor fails as well", ex);
			}
		}

		((Factory) proxyInstance).setCallbacks(callbacks);
		return proxyInstance;
	}

Finally also set some callback is:

learned here almost know how to generate AOPthe proxy, and goes on to see which method is how to perform it.

Well, here today, we hope to help study and understand, do not spray the Great God see, understand only their own learning, limited capacity, please excuse.