1、代理技术（静态代理、JDK动态代理、CGLib代理）
静态代理：|-- Hello |-- void say(String name);|-- HelloImpl implements Hello {voiv say(String name){ sysout("Hello!"+name);}}|-- HelloProxy implents Hello { Hello hello; HelloProxy(){ hello = new HelloImpl(); } voiv say(String name){ before(); sysout("Hello!"+name); end(); } void before(){ sysout("Before"); } void after(){ sysout("After"); } main(String[] args){ Hello hello = new HelloProxy(); hello.say("Jack"); }}JDK动态代理：|-- DynamicProxy implements InvocationHandler { Object target; DynamicProxy (Object target){ this.target = target; } @Override public Object invoke(Object proxy, Method method, Object[] args){ before(); object result = method.invoke(target, args); after(); return result; } ... main(String[] args){ // 尝试1 Hello hello = new HelloImpl(); DynamicProxy dynamicProxy = new DynamicProxy(hello); Hello hello = (Hello)Proxy.newProxyInstance(hello.getClass().getClassLoader(), hello.getClass.getInterfaces(), dynamicProxy); hello.say("Jack"); // 尝试2 DynamicProxy dynamicProxy = new DynamicProxy(new HelloImpl()); Hello hello = dynamicProxy.getProxy(); hello.say("Jack"); } public T getProxy(){ return (T)Proxy.newProxyInstance( target.getClass().getClassLoader(), target.getClass.getInterfaces(), this ); }}CGLib动态代理：|-- CGLibProxy implements MethodInterceptor { private static CGLibProxy instance = new CGLibProxy(); private CGLibProxy() {} public CGLibProxy getInstance(){ return instance; } public T getProxy(Class cls){ return (T) Enhancer.create(cls, this); } public Object inercept(Object obj, Method method, Object[] args, MethodProxy proxy){ before(); Object result = proxy.invokeSuper(obj, args); after(); return result; } ... main(String[] args){ // 尝试1 CGLibProxy cgLibProxy = new CGLibProxy(); Hello helloProxy = cgLibProxy.getProxy(HelloImpl.class); helloProxy.say("Jack"); // 尝试2 Hello helloProxy =CGLibProxy.getInstance().getProxy(HelloImpl.class); helloProxy.say("Jack"); }} 2、AOP技术
|-- interface Greeting |-- void sayHello(String name);|-- GreetingImpl implements Greeting|-- sayHello(String name){ before(); sysout("Hello!"+name); after();}|-- GreetingProxy implements Greeting|-- GreetingImpl greetingImpl;|-- GreetingProxy(GreetingImpl greetingImpl) -> this.greetingImpl = greetingImpl;|-- sayHello(String name){ before(); greetingImpl.sayHello(); after();}|-- before() -> sysout("Before");|-- after() -> sysout("After");|-- main(String[] args){ Greeting greetingProxy = new GreetingProxy(new GreetingImpl()); greetingProxy.sayHello("Jack");}|-- JDKDynamicProxy implements InvocationHandler { Object target; JDKDynamicProxy (Object target){ this.target = target; } @Override public Object invoke(Object proxy, Method method, Object[] args){ before(); object result = method.invoke(target, args); after(); return result; } public T getProxy(){ return (T)Proxy.newProxyInstance( target.getClass().getClassLoader(), target.getClass.getInterfaces(), this ); } private void before(){ sysout("Before"); } private void after(){ sysout("After"); } main(String[] args){ Greeting greeting = new JDKDynamicProxy(new GreetingImpl()).getProxy(); greeting.sayHello("Jack"); }}|-- CGLibProxy implements MethodInterceptor{ private static CGLibProxy instance = new CGLibProxy(); private CGLibProxy() {} public CGLibProxy getInstance(){ return instance; } public T getProxy(Class cls){ return (T) Enhancer.create(cls, this); } public Object inercept(Object obj, Method method, Object[] args, MethodProxy proxy){ before(); Object result = proxy.invokeSuper(obj, args); after(); return result; } main(String[] args){ Greeting greeting = CGLibProxy.getInstance().getProxy(GreetingImpl.class); greeting.sayHello("Jack"); }} 3、spring AOP技术
|-- GreetingBeforeAdvice implements MethodBeforeAdvice |-- before(Method method, Object[] args, Object target) throws Throwable -> sysout("Before");|-- AfterReturningAdvice |-- afterReturning(Object result, Method method, Object[] args, Object target) throws Throwable -> sysout("after");|-- GreetingBeforeAndAfterAdvice implements MethodBeforeAdvice, AfterReturningAdvice |-- before(Method method, Object[] args, Object target) throws Throwable -> sysout("Before"); |-- afterReturning(Object result, Method method, Object[] args, Object target) throws Throwable -> sysout("after");|-- GreetingAroundAdvice implements MethodInterceptor // 环绕增强（org.aopalliance.intercept.MethodInterceptor，AOP联盟） |-- Object invoke(MethodInvocation invocation){ before(); Object result = invocation.proceed(); after(); } |-- before() -> sysout("Before") |-- after() -> sysout("After")|-- main (String[] args){ ProxyFactory proxyFactory = new ProxyFactory(); // 创建代理工厂 proxyFactory.setTarget(new GreetingImpl()); // 射入目标类对象 // proxyFactory.addAdvice(new GreetingBeforeAdvice()); // 添加前置增强 // proxyFactory.addAdvice(new AfterReturningAdvice()); // 添加后置增强 // proxyFactory.addAdvice(new GreetingBeforeAndAfterAdvice()); // 添加前后置增强 proxyFactory.addAdvice(new GreetingAroundAdvice()); // 添加环绕增强 Greeting greeting = (Greeting)proxyFactory.getProxy(); // 从代理工厂获取代理对象 greeting.sayHello("Jack"); // 调用代理方法 }|-- 配置文件-spring.xml greetingAroundAdvice
spring2.5+特性，@Component @Component public calss GreetingImpl implements Greeting { ... } --> |-- 客户端调用 |-- main(String[] args){ ApplicationContext context = new ClassPathXmlApplicationContext("aop/demo/spring.xml"); Greeting greeting = (Greeting)context.getBean("greetingProxy"); greeting.sayHello("Jack"); }|-- 抛出增强-ThrowsAdvice |-- GreetingThrowAdvice implements ThrowsAdvice { public void afterThrowing(Method method, Object[] args, Object target, Exception e){ sysout("--------- Throw Exception ---------"); sysout("Target Class: " + target.getClass().getName()); sysout("Method Name: " + method.getName()); sysout("Exception Message: " + e.getMessage()); sysout("-----------------------------------"); } }|-- 引入增强 |-- interface Apology |-- void saySorry(String name); |-- @Component GreetingIntroAdvice extends DelegatingIntroductionInterceptor implements Apology { @Override public Object invoke(MethodInvocation invocation) throws Throwable{ return super.invoke(invocation); } @Overrice public void saySorry(String name){ sysout("Sorry! + name); } } |-- 配置文件-spring.xml |-- 调用 |-- main(String[] args){ ApplicationContext context = new ClassPathXmlApplicationContext("aop/demo/spring.xml"); GeetingImpl greetingImpl = (GeetingImpl)context.getBean("greetingProxy"); // 转型为目标类，而非它的接口 greetingImpl.sayHello("Jack"); Apology apology = (Apology) greetingImpl; // 将目标类型强制向上转型为Apology接口（这就是引入增强给我们带来的特性，也就是“接口动态实现”功能） apology.saySorry("Jack"); }|-- AOP 切面 |-- @Component public class GreetingImpl implements Greeting { @Override public void sayHello(){ sysout("Hello!" + name); } public void goodMorning(String name){ sysout("Good Morning!" + name); } public void goodNight(String name){ sysout("Good Night!" + name); } } |-- 配置文件-spring.xml |-- AOP自动代理（每一个类都需要配置切面太麻烦，因此需要自动生成代理） |-- 配置文件-spring.xml *Impl -> 不清楚Bean实现了多少接口，不能代理接口，只能代理类。 |-- 匹配到目标类的指定方法 |-- 配置文件-spring.xml --> 总结： CGLib代理：创建代理速度慢，创建代理后运行速度快（系统初始化创建代理备用最佳） JDK动态代理：创建代理速度快，运行速度慢 |-- spring + AspectJ（Advisor）|-- 普通demo |-- @Aspect @Component public class GreetingAspect { @Arount("execution(* aop.demo.GreetingImpl.*(..))") public Object around(ProceedingJoinPoint pjp) throws Throwable { before(); Object result = pjp.proceed(); after(); return result; } public void before(){ sysout("Before"); } public void after(){ sysout("after"); } } |-- 配置文件-spring.xml 4、开发aop框架
|-- 定义注解类：|-- @Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)public @Interface Aspect { Class value();}|-- 搭建代理框架|-- interface Proxy { 代理接口 // 执行链式代理：可将多个代理通过一条链子串起来，一个个地去执行，执行顺序取决于添加到链上的先后顺序 Object doProxy(ProxyChain proxyChain) throws Throwable;}|-- class ProxyChain // 代理链|-- Class targetClass;|-- Object targetObject;}-- Method targetMethod;|-- MethodProxy methodProxy;}-- Object[] methodParams;|-- List proxyList = new ArrayList<>();|-- int proxyIndex=0;|-- ProxChain(Class targetClass,Object targetObject,Method targetMethod,MethodProxy methodProxy,Object[] methodParams,List proxyList){ this.targetClass = targetClass; ... }|-- getMethodParams() -> return methodParams;|-- getTargetClass() -> return targetClass;|-- getTargetMethod() -> return targetMethod;|-- Object doProxyChain() throws throwable{ Object methodResult; if (proxyIndex < proxyList.size()){ methodResult = proxyList.get(proxyIndex++).doProxy(); } else { methodResult = methodProxy.invokeSuper(targetObject, methodParams); } return methodResult; }|-- 添加pom.xml依赖 cglib ...|-- class ProxyManger // 代理管理类|-- T createProxy(final Class targetClass, final List proxyList){ return (T) Enhancer.create(targetClass, new MethodInterceptor(){ @Overrice public Object intercept(Object targetObject, Method targetMethod, Object[] methodParams, MethodProxy methodProxy){ return new ProxyChain(targetClass, targetObject, targetMethod, methodProxy, methodParams, proxyList); } }); }|-- public abstract calss AspectProxy implements Proxy { // 切面代理 @Override public final Object doProxy(ProxyChain proxyChain) throws throwable { Object result = null; Class cls = proxyChain.getTargetClass(); Method method = proxyChain.getTargetMethod(); Object[] params = proxyChain.getMethodParams(); begin(); try { if (intercept(cls, method, params)){ before(cls, method, params); result = proxyChain.doProxyChain(); after(cls, method, params); } else { return proxyChain.doProxyChain(); } } catch(Exception e){ logger.error("proxy failure", e); error(cls, method, params, e); throw e; } finally { end(); } } public void begin(){ } public void end(){ } public boolean intercept(Class cls, Method method, Object[] params) throws Throwable { return true; } public void before(Class cls, Method method, Object[] params) throws Throwable { } public void after(Class cls, Method method, Object[] params) throws Throwable { } public void error(Class cls, Method method, Object[] params, Throwable e){ }}|-- @Aspect(Controller.class)ControllerAspect extends AspectProxy{ // 拦截Controller 所有方法 private long begin; @Override public void before(Class cls, Method method, Object[] params) throws Throwable { begin = System.currentTimeMillis(); } @Override public void after(Class cls, Method method, Object[] params) throws Throwable { sysout(System.currentTimeMillis()-begin); }}|-- BeanHelper { ... // 设置bean实例 public static void setBean(Class cls, Object obj){ BEAN_MAP.put(cls, obj); }} |-- ClassHelper { ... // 获取某父类（或接口）的所有子类（或实现类） public static Set > getClassSetBySuper(Class superClass){ Set > classSet = new HashSet (); for(Class cls : CLASS_SET){ if (superClass.isAssignableFrom(cls) && !superClass.equals(cls)){ classSet.add(cls); } } } // 获取应用包名下带有注解的所有类 public static Set > getClassSetByAnnotation(Class annotionClass){ Set > classSet = new HashSet (); for(Class cls : CLASS_SET){ if (superClass.isAnnotationPresent(annotionClass)){ classSet.add(cls); } } } ...}|-- AopHelper { ... private static Set > createTargetClassSet(Aspect aspect) throws Exception { Set > targetClassSet = new HashSet >(); Class annotation = aspect.value(); if (annotation != null && !annotation.equals(Aspect.class)){ targetClassSet.addAll(ClassHelper.getClassSetByAnnotation(annotation)); } return targetClassSet; } private static Map >,Set >> createProxyMap() throws Exception { Map >,Set >> proxyMap = new HashMap >,Set >>(); Set > proxyClassSet = ClassHelper.getClassSetByAnnotation(AspectProxy.class); for(Class proxyClass : proxyClassSet){ if (proxyClass.isAnnotationPresent(Aspect.class)){ Aspect aspect = proxyClass.getAnnotation(Aspect.class); Set > targetClassSet = createTargetClassSet(aspect); proxyMap.put(proxyClass, targetClassSet); } } return proxyMap; } private static Map ,List > createTargetMap(Map >,Set >> proxyMap) throws Exception { Map ,List > targetMap = new HashMap ,List >(); for(Map.Entry >,Set >> proxyEntry : proxyMap.entrySet()){ Class proxyClass = proxyEntry.getKey(); Set targetClassSet = proxyEntry.getValue(); for(Class targetClass : targetClassSet){ Proxy proxy = (Proxy) targetClass.newInstance(); if (targetMap.contains(targetClass)){ targetMap.get(targetClass).add(proxy); } else { List proxyList = new ArrayList (); proxyList.add(proxy); targetMap.put(targetClass, proxyList); } } } } static { try { Map >,Set >> proxyMap = createProxyMap(); Map ,List > targetMap = createTargetMap(proxyMap); for(Map.Entry ,List > targetEntry : targetMap.etrySet()){ Class targetClass =targetEntry.getKey(); List proxyList = targetEntry.getValue(); Object proxy = ProxyManager.createProxy(targetClass, proxyList); BeanHelper.setBean(targetClass, proxy); } } catch(Exception e){ Logger.error("aop failure", e); } }}|-- HelperLoader { public static void init(){ Class [] classList = { ClassHelper.class, BeanHelper.class, AopHelper.class, IocHelper.class, ControllerHelper.class }; for(Class cls : classList){ ClassUtil.loadClass(cls.getName(), true); } }}