这个接口的继承体系图：
一、AopProxy
InvocationHandler就不说了，看看AopProxy的源码。
/**
* Delegate interface for a configured AOP proxy, allowing for the creation
* of actual proxy objects.
*
* <p>Out-of-the-box implementations are available for JDK dynamic proxies
* and for CGLIB proxies, as applied by {@link DefaultAopProxyFactory}.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see DefaultAopProxyFactory
*/
public interface AopProxy { /**创建一个代理对象。（为目标对象创建一个代理对象。）
* Create a new proxy object.
* <p>Uses the AopProxy's default class loader (if necessary for proxy creation):
* usually, the thread context class loader.
* @return the new proxy object (never {@code null})
* @see Thread#getContextClassLoader()
*/
Object getProxy(); /**重载方法。上面的无参方法会调用这个重载方法。
* Create a new proxy object.
* <p>Uses the given class loader (if necessary for proxy creation).
* {@code null} will simply be passed down and thus lead to the low-level
* proxy facility's default, which is usually different from the default chosen
* by the AopProxy implementation's {@link #getProxy()} method.
* @param classLoader the class loader to create the proxy with
* (or {@code null} for the low-level proxy facility's default)
* @return the new proxy object (never {@code null})
*/
Object getProxy(ClassLoader classLoader); }
二、JdkDynamicAopProxy
/**
* JDK-based {@link AopProxy} implementation for the Spring AOP framework,
* based on JDK {@link java.lang.reflect.Proxy dynamic proxies}.
*
* <p>Creates a dynamic proxy, implementing the interfaces exposed by
* the AopProxy. Dynamic proxies <i>cannot</i> be used to proxy methods
* defined in classes, rather than interfaces.
*
* <p>Objects of this type should be obtained through proxy factories,
* configured by an {@link AdvisedSupport} class. This class is internal
* to Spring's AOP framework and need not be used directly by client code.
*
* <p>Proxies created using this class will be thread-safe if the
* underlying (target) class is thread-safe.
*
* <p>Proxies are serializable so long as all Advisors (including Advices
* and Pointcuts) and the TargetSource are serializable.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Rob Harrop
* @author Dave Syer
* @see java.lang.reflect.Proxy
* @see AdvisedSupport
* @see ProxyFactory
*/
final class JdkDynamicAopProxy implements AopProxy, InvocationHandler, Serializable { /** use serialVersionUID from Spring 1.2 for interoperability */
private static final long serialVersionUID = 5531744639992436476L; /*
* NOTE: We could avoid the code duplication between this class and the CGLIB
* proxies by refactoring "invoke" into a template method. However, this approach
* adds at least 10% performance overhead versus a copy-paste solution, so we sacrifice
* elegance for performance. (We have a good test suite to ensure that the different
* proxies behave the same :-)
* This way, we can also more easily take advantage of minor optimizations in each class.
*/ /** We use a static Log to avoid serialization issues */
private static final Log logger = LogFactory.getLog(JdkDynamicAopProxy.class); /** Config used to configure this proxy */
private final AdvisedSupport advised; /**
* Is the {@link #equals} method defined on the proxied interfaces?
*/
private boolean equalsDefined; /**
* Is the {@link #hashCode} method defined on the proxied interfaces?
*/
private boolean hashCodeDefined; /**
* Construct a new JdkDynamicAopProxy for the given AOP configuration.
* @param config the AOP configuration as AdvisedSupport object
* @throws AopConfigException if the config is invalid. We try to throw an informative
* exception in this case, rather than let a mysterious failure happen later.
*/
public JdkDynamicAopProxy(AdvisedSupport config) throws AopConfigException {
Assert.notNull(config, "AdvisedSupport must not be null");
if (config.getAdvisors().length == 0 && config.getTargetSource() == AdvisedSupport.EMPTY_TARGET_SOURCE) {
throw new AopConfigException("No advisors and no TargetSource specified");
}
this.advised = config;
} @Override
public Object getProxy() {
return getProxy(ClassUtils.getDefaultClassLoader());
} @Override
public Object getProxy(ClassLoader classLoader) {
if (logger.isDebugEnabled()) {
logger.debug("Creating JDK dynamic proxy: target source is " + this.advised.getTargetSource());
}
//代理接口。代理对象的接口，通常包括目标对象的实现的接口、Advised接口、SpringProxy接口
Class<?>[] proxiedInterfaces = AopProxyUtils.completeProxiedInterfaces(this.advised, true);
findDefinedEqualsAndHashCodeMethods(proxiedInterfaces);
return Proxy.newProxyInstance(classLoader, proxiedInterfaces, this);//返回代理对象。
} /**
* Finds any {@link #equals} or {@link #hashCode} method that may be defined
* on the supplied set of interfaces.
* @param proxiedInterfaces the interfaces to introspect
*/
private void findDefinedEqualsAndHashCodeMethods(Class<?>[] proxiedInterfaces) {
for (Class<?> proxiedInterface : proxiedInterfaces) {
Method[] methods = proxiedInterface.getDeclaredMethods();
for (Method method : methods) {
if (AopUtils.isEqualsMethod(method)) {
this.equalsDefined = true;
}
if (AopUtils.isHashCodeMethod(method)) {
this.hashCodeDefined = true;
}
if (this.equalsDefined && this.hashCodeDefined) {
return;
}
}
}
} /**
* Implementation of {@code InvocationHandler.invoke}.
* <p>Callers will see exactly the exception thrown by the target,
* unless a hook method throws an exception.
*/
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
MethodInvocation invocation;
Object oldProxy = null;
boolean setProxyContext = false; TargetSource targetSource = this.advised.targetSource;
Class<?> targetClass = null;
Object target = null; try {
//是否重写了euquals方法，并且当前调用的方法就是的equals方法.
if (!this.equalsDefined && AopUtils.isEqualsMethod(method)) {
// The target does not implement the equals(Object) method itself.
return equals(args[0]);
}
else if (!this.hashCodeDefined && AopUtils.isHashCodeMethod(method)) {
// The target does not implement the hashCode() method itself.
//是否重写了hashCode方法并且当前调用的是hashCode方法。
return hashCode();
}
else if (method.getDeclaringClass() == DecoratingProxy.class) {
// There is only getDecoratedClass() declared -> dispatch to proxy config.
return AopProxyUtils.ultimateTargetClass(this.advised);
}
else if (!this.advised.opaque && method.getDeclaringClass().isInterface() &&
method.getDeclaringClass().isAssignableFrom(Advised.class)) {
// Service invocations on ProxyConfig with the proxy config...
return AopUtils.invokeJoinpointUsingReflection(this.advised, method, args);
} Object retVal; if (this.advised.exposeProxy) {
// Make invocation available if necessary.
oldProxy = AopContext.setCurrentProxy(proxy);
setProxyContext = true;
} // May be null. Get as late as possible to minimize the time we "own" the target,
// in case it comes from a pool.
//尽量晚点获取目标对象。
target = targetSource.getTarget();
if (target != null) {
targetClass = target.getClass();
} // Get the interception chain for this method.获取目标方法对应的拦截器链
List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass); // Check whether we have any advice. If we don't, we can fallback on direct
// reflective invocation of the target, and avoid creating a MethodInvocation.
if (chain.isEmpty()) {//如果拦截器链为空，那么直接调用目标对象。
// We can skip creating a MethodInvocation: just invoke the target directly
// Note that the final invoker must be an InvokerInterceptor so we know it does
// nothing but a reflective operation on the target, and no hot swapping or fancy proxying.
//拦截器链为空的话就不需要创建MethodInvocation对象（连接点）了,直接调用目标对象。
Object[] argsToUse = AopProxyUtils.adaptArgumentsIfNecessary(method, args);
retVal = AopUtils.invokeJoinpointUsingReflection(target, method, argsToUse);
}
else {
// We need to create a method invocation...
//拦截器链不为空，创建一个调用
invocation = new ReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain);
// Proceed to the joinpoint through the interceptor chain.
//开始调用拦截器链和目标方法.
retVal = invocation.proceed();
} // Massage return value if necessary.
Class<?> returnType = method.getReturnType();
if (retVal != null && retVal == target &&
returnType != Object.class && returnType.isInstance(proxy) &&
!RawTargetAccess.class.isAssignableFrom(method.getDeclaringClass())) {
// Special case: it returned "this" and the return type of the method
// is type-compatible. Note that we can't help if the target sets
// a reference to itself in another returned object.
retVal = proxy;
}
else if (retVal == null && returnType != Void.TYPE && returnType.isPrimitive()) {
throw new AopInvocationException(
"Null return value from advice does not match primitive return type for: " + method);
}
return retVal;
}
finally {
if (target != null && !targetSource.isStatic()) {
// Must have come from TargetSource.
targetSource.releaseTarget(target);
}
if (setProxyContext) {
// Restore old proxy.
AopContext.setCurrentProxy(oldProxy);
}
}
} /**
* Equality means interfaces, advisors and TargetSource are equal.
* <p>The compared object may be a JdkDynamicAopProxy instance itself
* or a dynamic proxy wrapping a JdkDynamicAopProxy instance.
*/
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if (other == null) {
return false;
} JdkDynamicAopProxy otherProxy;
if (other instanceof JdkDynamicAopProxy) {
otherProxy = (JdkDynamicAopProxy) other;
}
else if (Proxy.isProxyClass(other.getClass())) {
InvocationHandler ih = Proxy.getInvocationHandler(other);
if (!(ih instanceof JdkDynamicAopProxy)) {
return false;
}
otherProxy = (JdkDynamicAopProxy) ih;
}
else {
// Not a valid comparison...
return false;
} // If we get here, otherProxy is the other AopProxy.
return AopProxyUtils.equalsInProxy(this.advised, otherProxy.advised);
} /**
* Proxy uses the hash code of the TargetSource.
*/
@Override
public int hashCode() {
return JdkDynamicAopProxy.class.hashCode() * 13 + this.advised.getTargetSource().hashCode();
} }