先定義一個接口,裏面定義目標方法java
//目標類要實現的接口 public interface ITarget { //目標方法 void doFunc(String words); }
定義一個代理類spring
public class StaticProxy implements ITarget{ private ITarget target = null; //關聯要加強的目標類 public StaticProxy(ITarget target){ this.target = target; } //在這裏加強目標類的目標方法 @Override public void doFunc() { ... ... ... //加強目標方法 target.doFunc(); ... ... ... } }
之後,任意的一個ITarget接口的子類,均可以注入給StaticProxy類,而後實現一套加強,再也不贅述。緩存
代理類在程序運行時建立的代理方式被成爲 動態代理。也就是說,這種狀況下,代理類並非像靜態代理同樣,是在Java代碼中定義的,而是在運行時根據咱們在Java代碼中的「指示」動態生成的。app
動態代理是spring AOP的實現原理,spring有兩種動態代理模式,cglib和jdk,咱們先來將java jdk的動態代理。框架
首先,咱們須要知道,jdk的動態代理只能代理實現了接口的類 沒有實現接口的類不能實現JDK動態代理。其次,咱們還要了解一個重要的中介接口InvocationHandler,這是jdk的動態代理的基石,它的定義以下:ide
public interface InvocationHandler { public Object invoke(Object proxy, Method method, Object[] args) throws Throwable; }
咱們先來寫一個jdk的動態代理實例,再來討論其中的原理吧函數
咱們先來定義一個目標類,或者說委託類,或者又叫被代理類,它實現了咱們上面定義的那個接口ITarget:工具
public class Entrust implements ITarget { public void doFunc(String words){ System.out.println(words); } }
再定義一箇中介類,實現InvocationHandler接口,這個中介類,持有被代理的對象,在invoke中利用反射,調用目標類的方法:ui
public class JdkDynamicProxyHandler<T> implements InvocationHandler { //invocationHandler持有的被代理對象 T target; public JdkDynamicProxyHandler(T target) { this.target = target; } /** * proxy:表明動態代理對象 * method:表明正在執行的方法 * args:表明調用目標方法時傳入的實參 * */ @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { System.out.println("do before"); Object result = method.invoke(target, args); System.out.println("do after"); return result; } }
好了,咱們如今來寫一個代理demo:this
public static void main(String[] a){ //建立一個實例對象,這個對象是被代理的對象 ITarget attorney = new Attorney(); //建立一個與代理對象相關聯的InvocationHandler InvocationHandler jdkDynamicProxyHandler = new JdkDynamicProxyHandler<ITarget>(attorney); //建立一個代理對象proxy來代理attorney,代理對象的每一個執行方法都會替換執行Invocation中的invoke方法 ITarget proxy = (ITarget) Proxy.newProxyInstance(ITarget.class.getClassLoader(), new Class<?>[]{ITarget.class}, jdkDynamicProxyHandler); //代理執行上交班費的方法 proxy.doFunc("hello word"); //將生成的代理類寫到桌面 writeProxyClassToHardDisk("/home/ls/Desktop/$Proxy22.class"); } public static void writeProxyClassToHardDisk(String path) { byte[] classFile = ProxyGenerator.generateProxyClass("$Proxy22", Attorney.class.getInterfaces()); FileOutputStream out = null; try { out = new FileOutputStream(path); out.write(classFile); out.flush(); } catch (Exception e) { e.printStackTrace(); } finally { try { out.close(); } catch (IOException e) { e.printStackTrace(); } } }
最後輸出:
咱們來看看Proxy.newProxyInstance方法
public static Object newProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler h) throws IllegalArgumentException { Objects.requireNonNull(h); final Class<?>[] intfs = interfaces.clone(); final SecurityManager sm = System.getSecurityManager(); if (sm != null) { //驗證一些參數 checkProxyAccess(Reflection.getCallerClass(), loader, intfs); } /* * Look up or generate the designated proxy class. * 從緩存裏面獲取某個類的代理類,若是該類的代理類不存在,就根據該類的類型建立一個 * 若是要深挖邏輯,能夠看看ProxyClassFactory的apply方法。 * 其實生成代理類字節碼文件的工做是經過 ProxyGenerate類中的generateProxyClass方法來完成的。 */ Class<?> cl = getProxyClass0(loader, intfs); /* * Invoke its constructor with the designated invocation handler. * * /** parameter types of a proxy class constructor */ * private static final Class<?>[] constructorParams = { InvocationHandler.class }; * */ try { if (sm != null) { checkNewProxyPermission(Reflection.getCallerClass(), cl); } //看上面的註釋,constructorParams={ InvocationHandler.class }, //這是在生成代理類的構造函數,得到一個參數爲InvocationHandler的構造方法 final Constructor<?> cons = cl.getConstructor(constructorParams); final InvocationHandler ih = h; if (!Modifier.isPublic(cl.getModifiers())) { AccessController.doPrivileged(new PrivilegedAction<Void>() { public Void run() { cons.setAccessible(true); return null; } }); } //這行代碼的意思是將h,也就是實現InvocationHandler的實現類, //咱們傳入的是jdkDynamicProxyHandler,注入到cons中。 //而後newInstance生成一個已經組裝過參數的代理類。 return cons.newInstance(new Object[]{h}); } catch (IllegalAccessException|InstantiationException e) { throw new InternalError(e.toString(), e); } catch (InvocationTargetException e) { Throwable t = e.getCause(); if (t instanceof RuntimeException) { throw (RuntimeException) t; } else { throw new InternalError(t.toString(), t); } } catch (NoSuchMethodException e) { throw new InternalError(e.toString(), e); } }
咱們最應該關注的是 Class<?> cl = getProxyClass0(loader, intfs);這句,這裏產生了代理類,後面代碼中的構造器也是經過這裏產生的類來得到,能夠看出,這個類的產生就是整個動態代理的關鍵,因爲是動態生成的類文件,我這裏不具體進入分析如何產生的這個類文件,只須要知道這個類文件時緩存在java虛擬機中的。
咱們對這個代理類進行反編譯:(本次使用http://www.javadecompilers.co...)
import java.lang.reflect.UndeclaredThrowableException; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import aopLearn.ITarget; import java.lang.reflect.Proxy; // // Decompiled by Procyon v0.5.30 // public final class $Proxy22 extends Proxy implements ITarget { private static Method m1; private static Method m3; private static Method m2; private static Method m0; /** *注意這裏是生成代理類的構造方法,方法參數爲InvocationHandler類型,看到這,是否是就有點明白了 *爲什麼代理對象調用方法都是執行InvocationHandler中的invoke方法,而InvocationHandler又持有一個 *被代理對象的實例 * *super(paramInvocationHandler),是調用父類Proxy的構造方法。 *父類持有:protected InvocationHandler h; *Proxy構造方法: * protected Proxy(InvocationHandler h) { * Objects.requireNonNull(h); * this.h = h; * } * */ public $Proxy22(final InvocationHandler invocationHandler) { super(invocationHandler); } //這個靜態塊原本是在最後的,我把它拿到前面來,方便描述 static { try { //doFunc經過反射獲得的名字m3 $Proxy22.m1 = Class.forName("java.lang.Object").getMethod("equals", Class.forName("java.lang.Object")); $Proxy22.m3 = Class.forName("aopLearn.ITarget").getMethod("doFunc", Class.forName("java.lang.String")); $Proxy22.m2 = Class.forName("java.lang.Object").getMethod("toString", (Class<?>[])new Class[0]); $Proxy22.m0 = Class.forName("java.lang.Object").getMethod("hashCode", (Class<?>[])new Class[0]); } catch (NoSuchMethodException ex) { throw new NoSuchMethodError(ex.getMessage()); } catch (ClassNotFoundException ex2) { throw new NoClassDefFoundError(ex2.getMessage()); } } public final boolean equals(final Object o) { try { return (boolean)super.h.invoke(this, $Proxy22.m1, new Object[] { o }); } catch (Error | RuntimeException error) { throw; } catch (Throwable t) { throw new UndeclaredThrowableException(t); } } /** * *這裏調用代理對象的doFunc方法,直接就調用了InvocationHandler中的invoke方法,並把m3傳了進去。 *this.h.invoke(this, m3, null);這裏簡單,明瞭。 *代理對象持有一個InvocationHandler對象,InvocationHandler對象持有一個被代理的對象, *再聯繫到InvacationHandler中的invoke方法。其實就是代理對象調用InvocationHandler, * InvocationHandler對象反射調用委託類對象。 */ public final void doFunc(final String s) { try { super.h.invoke(this, $Proxy22.m3, new Object[] { s }); } catch (Error | RuntimeException error) { throw; } catch (Throwable t) { throw new UndeclaredThrowableException(t); } } public final String toString() { try { return (String)super.h.invoke(this, $Proxy22.m2, null); } catch (Error | RuntimeException error) { throw; } catch (Throwable t) { throw new UndeclaredThrowableException(t); } } public final int hashCode() { try { return (int)super.h.invoke(this, $Proxy22.m0, null); } catch (Error | RuntimeException error) { throw; } catch (Throwable t) { throw new UndeclaredThrowableException(t); } } }
看完了這些,咱們來想一下,爲何jdk的動態代理,必定要委託類實現一個接口?這是由於咱們能夠看到,咱們生成的代理類Proxy22 extends Proxy implements ITarget,已經繼承了Proxy類,而java中不能多繼承,爲了讓$Proxy22和委託類創建聯繫,只能實現一個接口。這裏的創建聯繫,是指經過接口,獲得委託類方法的反射等,而且,委託類實現自接口的方法,才能被加強。
故而,本質上來講,jdk的動態代理,是爲接口產生代理。
在spring AOP中,咱們使用jdk動態代理時固然也要定義InvocationHandler的實現類對象,spring中的是org.springframework.aop.framework.JdkDynamicAopProxy類。
cglib的動態代理針對類來實現代理,對指定目標產生一個子類 經過方法攔截技術攔截全部父類方法的調用。咱們要使用cglib代理必須引入cglib的jar包。
一樣,定義一個跟上面例子同樣的委託類。
public class Entrust { public void doFunc(String words){ System.out.println(words); } }
實現MethodInterceptor接口生成方法攔截器
public class EntrustInterceptor implements MethodInterceptor{ @Override public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { System.out.println("before"); Object o = proxy.invokeSuper(obj,args); System.out.println("after"); return o; } }
實例以下:
public static void main(String[] a){ //cglib自帶的debug工具,能夠將代理類輸出到指定路徑 System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "/home/ls/Desktop/cglib"); Enhancer enhancer = new Enhancer(); //繼承被代理類 enhancer.setSuperclass(Entrust.class); enhancer.setCallback(new EntrustInterceptor()); //生成的代理類對象 Entrust entrust = (Entrust) enhancer.create(); //在調用咱們代理類中的方法時會被咱們實現的方法攔截器攔截 entrust.doFunc("hello word"); }
輸出結果以下:
CGLIB會讓生成的代理類繼承被代理類,並在代理類中對代理方法進行強化處理(前置處理、後置處理等)。在CGLIB底層,實際上是藉助了ASM這個很是強大的Java字節碼生成框架。
咱們看到,代理類對象是由Enhancer類建立的。Enhancer是CGLIB的字節碼加強器,能夠很方便的對類進行拓展,建立代理對象的幾個步驟:
咱們來看看將代理類Class文件反編譯以後的Java代碼,一個動態代理,產生了三個類:
主要的代理類是
Entrust$$EnhancerByCGLIB$$832e20ab
// // Decompiled by Procyon v0.5.30 // package com.lufax.util.aopCache.cglibProxy; import net.sf.cglib.core.Signature; import net.sf.cglib.core.ReflectUtils; import net.sf.cglib.proxy.MethodProxy; import java.lang.reflect.Method; import net.sf.cglib.proxy.MethodInterceptor; import net.sf.cglib.proxy.Callback; import net.sf.cglib.proxy.Factory; /** * 生成的代理類Entrust$$EnhancerByCGLIB$$832e20ab繼承被代理類Entrust。 * 在這裏咱們須要注意一點:若是委託類被final修飾,那麼它不可被繼承,即不可被代理; * 一樣,若是委託類中存在final修飾的方法,那麼該方法也不可被代理; * */ public class Entrust$$EnhancerByCGLIB$$832e20ab extends Entrust implements Factory { private boolean CGLIB$BOUND; private static final ThreadLocal CGLIB$THREAD_CALLBACKS; private static final Callback[] CGLIB$STATIC_CALLBACKS; private MethodInterceptor CGLIB$CALLBACK_0; private static final Method CGLIB$doFunc$0$Method; private static final MethodProxy CGLIB$doFunc$0$Proxy; private static final Object[] CGLIB$emptyArgs; private static final Method CGLIB$finalize$1$Method; private static final MethodProxy CGLIB$finalize$1$Proxy; private static final Method CGLIB$equals$2$Method; private static final MethodProxy CGLIB$equals$2$Proxy; private static final Method CGLIB$toString$3$Method; private static final MethodProxy CGLIB$toString$3$Proxy; private static final Method CGLIB$hashCode$4$Method; private static final MethodProxy CGLIB$hashCode$4$Proxy; private static final Method CGLIB$clone$5$Method; private static final MethodProxy CGLIB$clone$5$Proxy; static void CGLIB$STATICHOOK1() { CGLIB$THREAD_CALLBACKS = new ThreadLocal(); CGLIB$emptyArgs = new Object[0]; final Class<?> forName = Class.forName("com.lufax.util.aopCache.cglibProxy.Entrust$$EnhancerByCGLIB$$832e20ab"); final Class<?> forName2; final Method[] methods = ReflectUtils.findMethods(new String[] { "finalize", "()V", "equals", "(Ljava/lang/Object;)Z", "toString", "()Ljava/lang/String;", "hashCode", "()I", "clone", "()Ljava/lang/Object;" }, (forName2 = Class.forName("java.lang.Object")).getDeclaredMethods()); CGLIB$finalize$1$Method = methods[0]; CGLIB$finalize$1$Proxy = MethodProxy.create((Class)forName2, (Class)forName, "()V", "finalize", "CGLIB$finalize$1"); CGLIB$equals$2$Method = methods[1]; CGLIB$equals$2$Proxy = MethodProxy.create((Class)forName2, (Class)forName, "(Ljava/lang/Object;)Z", "equals", "CGLIB$equals$2"); CGLIB$toString$3$Method = methods[2]; CGLIB$toString$3$Proxy = MethodProxy.create((Class)forName2, (Class)forName, "()Ljava/lang/String;", "toString", "CGLIB$toString$3"); CGLIB$hashCode$4$Method = methods[3]; CGLIB$hashCode$4$Proxy = MethodProxy.create((Class)forName2, (Class)forName, "()I", "hashCode", "CGLIB$hashCode$4"); CGLIB$clone$5$Method = methods[4]; CGLIB$clone$5$Proxy = MethodProxy.create((Class)forName2, (Class)forName, "()Ljava/lang/Object;", "clone", "CGLIB$clone$5"); final Class<?> forName3; CGLIB$doFunc$0$Method = ReflectUtils.findMethods(new String[] { "doFunc", "(Ljava/lang/String;)V" }, (forName3 = Class.forName("com.lufax.util.aopCache.cglibProxy.Entrust")).getDeclaredMethods())[0]; CGLIB$doFunc$0$Proxy = MethodProxy.create((Class)forName3, (Class)forName, "(Ljava/lang/String;)V", "doFunc", "CGLIB$doFunc$0"); } //代理類會爲委託方法生成兩個方法,一個是重寫的doFunc方法, //另外一個是CGLIB$doFunc$0方法,咱們能夠看到它是直接調用父類的doFunc方法; final void CGLIB$doFunc$0(final String s) { super.doFunc(s); } //當執行代理對象的doFunc方法時,會首先判斷一下是否存在實現了MethodInterceptor接口的CGLIB$CALLBACK_0; //若是存在,則將調用MethodInterceptor中的intercept方法,如圖2.1。 public final void doFunc(final String s) { MethodInterceptor cglib$CALLBACK_2; MethodInterceptor cglib$CALLBACK_0; if ((cglib$CALLBACK_0 = (cglib$CALLBACK_2 = this.CGLIB$CALLBACK_0)) == null) { CGLIB$BIND_CALLBACKS(this); cglib$CALLBACK_2 = (cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0); } if (cglib$CALLBACK_0 != null) { //這裏開始調用咱們定義的EntrustInterceptor中的intercept方法。 //參數一、代理對象;二、委託類方法;三、方法參數;四、代理方法的MethodProxy對象(注意這個對象)。 cglib$CALLBACK_2.intercept((Object)this, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$doFunc$0$Method, new Object[] { s }, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$doFunc$0$Proxy); return; } super.doFunc(s); } final void CGLIB$finalize$1() throws Throwable { super.finalize(); } protected final void finalize() throws Throwable { MethodInterceptor cglib$CALLBACK_2; MethodInterceptor cglib$CALLBACK_0; if ((cglib$CALLBACK_0 = (cglib$CALLBACK_2 = this.CGLIB$CALLBACK_0)) == null) { CGLIB$BIND_CALLBACKS(this); cglib$CALLBACK_2 = (cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0); } if (cglib$CALLBACK_0 != null) { cglib$CALLBACK_2.intercept((Object)this, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$finalize$1$Method, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$emptyArgs, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$finalize$1$Proxy); return; } super.finalize(); } final boolean CGLIB$equals$2(final Object o) { return super.equals(o); } public final boolean equals(final Object o) { MethodInterceptor cglib$CALLBACK_2; MethodInterceptor cglib$CALLBACK_0; if ((cglib$CALLBACK_0 = (cglib$CALLBACK_2 = this.CGLIB$CALLBACK_0)) == null) { CGLIB$BIND_CALLBACKS(this); cglib$CALLBACK_2 = (cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0); } if (cglib$CALLBACK_0 != null) { final Object intercept = cglib$CALLBACK_2.intercept((Object)this, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$equals$2$Method, new Object[] { o }, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$equals$2$Proxy); return intercept != null && (boolean)intercept; } return super.equals(o); } final String CGLIB$toString$3() { return super.toString(); } public final String toString() { MethodInterceptor cglib$CALLBACK_2; MethodInterceptor cglib$CALLBACK_0; if ((cglib$CALLBACK_0 = (cglib$CALLBACK_2 = this.CGLIB$CALLBACK_0)) == null) { CGLIB$BIND_CALLBACKS(this); cglib$CALLBACK_2 = (cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0); } if (cglib$CALLBACK_0 != null) { return (String)cglib$CALLBACK_2.intercept((Object)this, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$toString$3$Method, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$emptyArgs, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$toString$3$Proxy); } return super.toString(); } final int CGLIB$hashCode$4() { return super.hashCode(); } public final int hashCode() { MethodInterceptor cglib$CALLBACK_2; MethodInterceptor cglib$CALLBACK_0; if ((cglib$CALLBACK_0 = (cglib$CALLBACK_2 = this.CGLIB$CALLBACK_0)) == null) { CGLIB$BIND_CALLBACKS(this); cglib$CALLBACK_2 = (cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0); } if (cglib$CALLBACK_0 != null) { final Object intercept = cglib$CALLBACK_2.intercept((Object)this, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$hashCode$4$Method, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$emptyArgs, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$hashCode$4$Proxy); return (intercept == null) ? 0 : ((Number)intercept).intValue(); } return super.hashCode(); } final Object CGLIB$clone$5() throws CloneNotSupportedException { return super.clone(); } protected final Object clone() throws CloneNotSupportedException { MethodInterceptor cglib$CALLBACK_2; MethodInterceptor cglib$CALLBACK_0; if ((cglib$CALLBACK_0 = (cglib$CALLBACK_2 = this.CGLIB$CALLBACK_0)) == null) { CGLIB$BIND_CALLBACKS(this); cglib$CALLBACK_2 = (cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0); } if (cglib$CALLBACK_0 != null) { return cglib$CALLBACK_2.intercept((Object)this, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$clone$5$Method, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$emptyArgs, Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$clone$5$Proxy); } return super.clone(); } public static MethodProxy CGLIB$findMethodProxy(final Signature signature) { final String string = signature.toString(); switch (string.hashCode()) { case -1574182249: { if (string.equals("finalize()V")) { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$finalize$1$Proxy; } break; } case -508378822: { if (string.equals("clone()Ljava/lang/Object;")) { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$clone$5$Proxy; } break; } case 346793840: { if (string.equals("doFunc(Ljava/lang/String;)V")) { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$doFunc$0$Proxy; } break; } case 1826985398: { if (string.equals("equals(Ljava/lang/Object;)Z")) { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$equals$2$Proxy; } break; } case 1913648695: { if (string.equals("toString()Ljava/lang/String;")) { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$toString$3$Proxy; } break; } case 1984935277: { if (string.equals("hashCode()I")) { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$hashCode$4$Proxy; } break; } } return null; } public Entrust$$EnhancerByCGLIB$$832e20ab() { CGLIB$BIND_CALLBACKS(this); } public static void CGLIB$SET_THREAD_CALLBACKS(final Callback[] array) { Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$THREAD_CALLBACKS.set(array); } public static void CGLIB$SET_STATIC_CALLBACKS(final Callback[] cglib$STATIC_CALLBACKS) { CGLIB$STATIC_CALLBACKS = cglib$STATIC_CALLBACKS; } private static final void CGLIB$BIND_CALLBACKS(final Object o) { final Entrust$$EnhancerByCGLIB$$832e20ab entrust$$EnhancerByCGLIB$$832e20ab = (Entrust$$EnhancerByCGLIB$$832e20ab)o; if (!entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$BOUND) { entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$BOUND = true; Object o2; if ((o2 = Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$THREAD_CALLBACKS.get()) != null || (o2 = Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$STATIC_CALLBACKS) != null) { entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$CALLBACK_0 = (MethodInterceptor)((Callback[])o2)[0]; } } } public Object newInstance(final Callback[] array) { CGLIB$SET_THREAD_CALLBACKS(array); final Entrust$$EnhancerByCGLIB$$832e20ab entrust$$EnhancerByCGLIB$$832e20ab = new Entrust$$EnhancerByCGLIB$$832e20ab(); CGLIB$SET_THREAD_CALLBACKS(null); return entrust$$EnhancerByCGLIB$$832e20ab; } public Object newInstance(final Callback callback) { CGLIB$SET_THREAD_CALLBACKS(new Callback[] { callback }); final Entrust$$EnhancerByCGLIB$$832e20ab entrust$$EnhancerByCGLIB$$832e20ab = new Entrust$$EnhancerByCGLIB$$832e20ab(); CGLIB$SET_THREAD_CALLBACKS(null); return entrust$$EnhancerByCGLIB$$832e20ab; } public Object newInstance(final Class[] array, final Object[] array2, final Callback[] array3) { CGLIB$SET_THREAD_CALLBACKS(array3); switch (array.length) { case 0: { final Entrust$$EnhancerByCGLIB$$832e20ab entrust$$EnhancerByCGLIB$$832e20ab = new Entrust$$EnhancerByCGLIB$$832e20ab(); CGLIB$SET_THREAD_CALLBACKS(null); return entrust$$EnhancerByCGLIB$$832e20ab; } default: { throw new IllegalArgumentException("Constructor not found"); } } } public Callback getCallback(final int n) { CGLIB$BIND_CALLBACKS(this); Object cglib$CALLBACK_0 = null; switch (n) { case 0: { cglib$CALLBACK_0 = this.CGLIB$CALLBACK_0; break; } default: { cglib$CALLBACK_0 = null; break; } } return (Callback)cglib$CALLBACK_0; } public void setCallback(final int n, final Callback callback) { switch (n) { case 0: { this.CGLIB$CALLBACK_0 = (MethodInterceptor)callback; break; } } } public Callback[] getCallbacks() { CGLIB$BIND_CALLBACKS(this); return new Callback[] { this.CGLIB$CALLBACK_0 }; } public void setCallbacks(final Callback[] array) { this.CGLIB$CALLBACK_0 = (MethodInterceptor)array[0]; } static { CGLIB$STATICHOOK1(); } }
邏輯進入到咱們在EntrustInterceptor 中定義的intercept方法
@Override public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { System.out.println("before"); Object o = proxy.invokeSuper(obj,args); System.out.println("after"); return o; }
咱們看看MethodProxy的invokeSuper方法:
/** * Invoke the original (super) method on the specified object. * @param obj the enhanced object, must be the object passed as the first * argument to the MethodInterceptor * @param args the arguments passed to the intercepted method; you may substitute a different * argument array as long as the types are compatible * @see MethodInterceptor#intercept * @throws Throwable the bare exceptions thrown by the called method are passed through * without wrapping in an <code>InvocationTargetException</code> */ public Object invokeSuper(Object obj, Object[] args) throws Throwable { try { init(); FastClassInfo fci = fastClassInfo; //f2是由CGlib生成的,在輸出的class中有這個類。 //它就是Entrust$$EnhancerByCGLIB$$832e20ab$$FastClassByCGLIB$$817a77c.class return fci.f2.invoke(fci.i2, obj, args); } catch (InvocationTargetException e) { throw e.getTargetException(); } }
咱們把
Entrust$$EnhancerByCGLIB$$832e20ab$$FastClassByCGLIB$$817a77c.class
也反編譯出來,而後貼出invoke方法,注意case14調用了
entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$doFunc$0((String)array[0]);:
public Object invoke(final int n, final Object o, final Object[] array) throws InvocationTargetException { final Entrust$$EnhancerByCGLIB$$832e20ab entrust$$EnhancerByCGLIB$$832e20ab = (Entrust$$EnhancerByCGLIB$$832e20ab)o; try { switch (n) { case 0: { entrust$$EnhancerByCGLIB$$832e20ab.setCallbacks((Callback[])array[0]); return null; } case 1: { Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$SET_STATIC_CALLBACKS((Callback[])array[0]); return null; } case 2: { Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$SET_THREAD_CALLBACKS((Callback[])array[0]); return null; } case 3: { return entrust$$EnhancerByCGLIB$$832e20ab.getCallback(((Number)array[0]).intValue()); } case 4: { return entrust$$EnhancerByCGLIB$$832e20ab.getCallbacks(); } case 5: { entrust$$EnhancerByCGLIB$$832e20ab.doFunc((String)array[0]); return null; } case 6: { entrust$$EnhancerByCGLIB$$832e20ab.setCallback(((Number)array[0]).intValue(), (Callback)array[1]); return null; } case 7: { return Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$findMethodProxy((Signature)array[0]); } case 8: { Entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$STATICHOOK1(); return null; } case 9: { entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$finalize$1(); return null; } case 10: { return entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$toString$3(); } case 11: { return new Integer(entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$hashCode$4()); } case 12: { return entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$clone$5(); } case 13: { return new Boolean(entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$equals$2(array[0])); } case 14: { entrust$$EnhancerByCGLIB$$832e20ab.CGLIB$doFunc$0((String)array[0]); return null; } case 15: { return new Boolean(entrust$$EnhancerByCGLIB$$832e20ab.equals(array[0])); } case 16: { return entrust$$EnhancerByCGLIB$$832e20ab.toString(); } case 17: { return new Integer(entrust$$EnhancerByCGLIB$$832e20ab.hashCode()); } case 18: { return entrust$$EnhancerByCGLIB$$832e20ab.newInstance((Callback)array[0]); } case 19: { return entrust$$EnhancerByCGLIB$$832e20ab.newInstance((Class[])array[0], (Object[])array[1], (Callback[])array[2]); } case 20: { return entrust$$EnhancerByCGLIB$$832e20ab.newInstance((Callback[])array[0]); } case 21: { Entrust.main((String[])array[0]); return null; } case 22: { entrust$$EnhancerByCGLIB$$832e20ab.wait(((Number)array[0]).longValue(), ((Number)array[1]).intValue()); return null; } case 23: { entrust$$EnhancerByCGLIB$$832e20ab.wait(((Number)array[0]).longValue()); return null; } case 24: { entrust$$EnhancerByCGLIB$$832e20ab.wait(); return null; } case 25: { return entrust$$EnhancerByCGLIB$$832e20ab.getClass(); } case 26: { entrust$$EnhancerByCGLIB$$832e20ab.notify(); return null; } case 27: { entrust$$EnhancerByCGLIB$$832e20ab.notifyAll(); return null; } } } catch (Throwable t) { throw new InvocationTargetException(t); } throw new IllegalArgumentException("Cannot find matching method/constructor"); }
事實證實,最後確實是進入了case14,調用了代理類的代理doFunc方法,最後再回到EntrustInterceptor.invoke中。完成邏輯
未完待續