一、前言
最近在探索Spring AOP的性能，发现最初是绕不开JDK动静代理和CGLIB动静代理这两个点。笔者心里大抵有这么个概念：对于动静代理来说，CGLIB性能要好于JDK。也晓得CGLIB是利用ASM技术基于继承子类实现动静代理，JDK是基于实现接口实现动静代理，然而对于底层实现还是比拟含糊。明天就彻底整明确CGLIB动静代理的底层实现。
二、前置筹备
（一）测试代码
CGLIB外围的几个概念：
- 被代理对象，本案例【Dog】
- 办法拦截器MethodInterceptor，本案例【CglibMethodInterceptor】
- Enhance代理对象生成工具，本案例【TestMain测试主类中创立】
1. 自定义办法拦截器CglibMethodInterceptor
前面也会将MethodInterceptor说成Callback，其实是一个货色，MethodInterceptor是实现了Callback接口的。
/**
* 办法拦截器,不必依赖被代理业务类的援用
*/
public class CglibMethodInterceptor implements MethodInterceptor {
/**
* 性能次要是在调用业务类办法之前 之后增加统计工夫的办法逻辑.
* intercept 因为具备 MethodProxy methodProxy 参数的起因,不再须要代理类的援用对象了,间接通过 methodProxy 对象拜访被代理对象的办法(这种形式更快)。
* 当然 也能够通过反射机制，通过 method 援用实例 Object result = method.invoke(target, args); 模式反射调用被代理类办法，
* target 实例代表被代理类对象援用, 初始化 CglibMethodInterceptor 时候被赋值 。然而Cglib不举荐应用这种形式
*
* @param object 代表Cglib 生成的动静代理类 对象自身
* @param method 代理类中被拦挡的接口办法 Method 实例
* @param args 接口办法参数
* @param methodProxy 用于调用父类真正的业务类办法。能够间接调用被代理类接口办法
* @return 被代理类办法执行返回值
* @throws Throwable
*/
@Override
public Object intercept(Object object, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
System.out.println("before");
MonitorUtil.start();
Object result = methodProxy.invokeSuper(object, args);
// Object result = methodProxy.invoke(object, args);
System.out.println("after");
MonitorUtil.finish(method.getName());
return result;
}
}2. 被代理类
public class Dog {
public String call() {
System.out.println("wang wang wang");
return "Dog ..";
}
}3. 切面办法
/**
* 办法用时监控类,作为一个切面 ，具备两个办法
*/
public class MonitorUtil {
private static final ThreadLocal<Long> tl = new ThreadLocal<>();
public static void start() {
tl.set(System.currentTimeMillis());
}
/**
* 完结时打印耗时
* @param methodName 监控办法名
*/
public static void finish(String methodName) {
long finishTime = System.currentTimeMillis();
System.out.println(methodName + "办法执行耗时" + (finishTime - tl.get()) + "ms");
}
}4. 测试主类
public class TestMain {
/**
* 用于生成 Cglib 动静代理类工具办法
* @param target 代表须要 被代理的 委托类的 Class 对象
* @return 代理类对象
*/
public static Object cglibProxyGenerator(Class target) {
// 创立增强器，用来创立动静代理类
Enhancer enhancer = new Enhancer();
// 为代理类指定须要代理的类，也即是父类
enhancer.setSuperclass(target);
// 设置办法拦截器回调援用，对于代理类上所有办法的调用，都会调用CallBack，而Callback则须要实现intercept() 办法进行拦挡
enhancer.setCallback(new CglibMethodInterceptor());
// 创立cglib 代理类
return enhancer.create();
}
public static void main(String[] args) throws ClassNotFoundException {
System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "classFiles");
Dog poolDog = (Dog) cglibProxyGenerator(Dog.class);
poolDog.call();
}
}（二）CGLIB生成的子类
Dog$$EnhancerByCGLIB$$beb9d601
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//
package com.allen.testDynamicProxy.cglibProxy;
import java.lang.reflect.Method;
import net.sf.cglib.core.ReflectUtils;
import net.sf.cglib.core.Signature;
import net.sf.cglib.proxy.Callback;
import net.sf.cglib.proxy.Factory;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
// 实现net.sf.cglib.proxy.Factory的目标是提供一些创立代理对象实例的工厂办法，这些办法会比反射创建对象快【clazz.newInstance()】
public class Dog$$EnhancerByCGLIB$$beb9d601 extends Dog implements Factory {
private boolean CGLIB$BOUND;
public static Object CGLIB$FACTORY_DATA;
private static final ThreadLocal CGLIB$THREAD_CALLBACKS;
private static final Callback[] CGLIB$STATIC_CALLBACKS;
private MethodInterceptor CGLIB$CALLBACK_0;
private static Object CGLIB$CALLBACK_FILTER;
// Dog类call的Method对象
private static final Method CGLIB$call$0$Method;
// Dog类call办法的代理对象
private static final MethodProxy CGLIB$call$0$Proxy;
private static final Object[] CGLIB$emptyArgs;
// Object类equals办法的Method对象
private static final Method CGLIB$equals$1$Method;
private static final MethodProxy CGLIB$equals$1$Proxy;
private static final Method CGLIB$toString$2$Method;
private static final MethodProxy CGLIB$toString$2$Proxy;
private static final Method CGLIB$hashCode$3$Method;
private static final MethodProxy CGLIB$hashCode$3$Proxy;
private static final Method CGLIB$clone$4$Method;
private static final MethodProxy CGLIB$clone$4$Proxy;
/**
* CGLIB$call$0$Method和CGLIB$call$0$Proxy就是MethodInterceptor接口的入参
* MethodProxy 比 Method反射调用办法更快
*/
static void CGLIB$STATICHOOK1() {
CGLIB$THREAD_CALLBACKS = new ThreadLocal();
CGLIB$emptyArgs = new Object[0];
// 加载生成的加强类
Class var0 = Class.forName("com.allen.testDynamicProxy.cglibProxy.Dog$$EnhancerByCGLIB$$beb9d601");
Class var1;
// 通过反射获取Object类的Method对象
Method[] var10000 = ReflectUtils.findMethods(new String[]{"equals", "(Ljava/lang/Object;)Z", "toString", "()Ljava/lang/String;", "hashCode", "()I", "clone", "()Ljava/lang/Object;"}, (var1 = Class.forName("java.lang.Object")).getDeclaredMethods());
CGLIB$equals$1$Method = var10000[0];
// 为 Method 创立对应的 MethodProxy 对象
CGLIB$equals$1$Proxy = MethodProxy.create(var1, var0, "(Ljava/lang/Object;)Z", "equals", "CGLIB$equals$1");
CGLIB$toString$2$Method = var10000[1];
CGLIB$toString$2$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/String;", "toString", "CGLIB$toString$2");
CGLIB$hashCode$3$Method = var10000[2];
CGLIB$hashCode$3$Proxy = MethodProxy.create(var1, var0, "()I", "hashCode", "CGLIB$hashCode$3");
CGLIB$clone$4$Method = var10000[3];
CGLIB$clone$4$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/Object;", "clone", "CGLIB$clone$4");
// Dog类call办法Method对象
CGLIB$call$0$Method = ReflectUtils.findMethods(new String[]{"call", "()Ljava/lang/String;"}, (var1 = Class.forName("com.allen.testDynamicProxy.cglibProxy.Dog")).getDeclaredMethods())[0];
CGLIB$call$0$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/String;", "call", "CGLIB$call$0");
}
final String CGLIB$call$0() {
return super.call();
}
// 重写 Dog类的call办法，增加CallBack回调【即执行MethodInterceptor的intercept办法，即咱们自定义的CglibMethodInterceptor的intercept办法】
public final String call() {
// 这边获取MethodInterceptor为null
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
// 从新绑定MethodInterceptor
CGLIB$BIND_CALLBACKS(this);
// 这边还是null
var10000 = this.CGLIB$CALLBACK_0;
}
return var10000 != null ? (String)var10000.intercept(this, CGLIB$call$0$Method, CGLIB$emptyArgs, CGLIB$call$0$Proxy) : super.call();
}
final boolean CGLIB$equals$1(Object var1) {
return super.equals(var1);
}
public final boolean equals(Object var1) {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
if (var10000 != null) {
Object var2 = var10000.intercept(this, CGLIB$equals$1$Method, new Object[]{var1}, CGLIB$equals$1$Proxy);
return var2 == null ? false : (Boolean)var2;
} else {
return super.equals(var1);
}
}
final String CGLIB$toString$2() {
return super.toString();
}
public final String toString() {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
return var10000 != null ? (String)var10000.intercept(this, CGLIB$toString$2$Method, CGLIB$emptyArgs, CGLIB$toString$2$Proxy) : super.toString();
}
final int CGLIB$hashCode$3() {
return super.hashCode();
}
public final int hashCode() {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
if (var10000 != null) {
Object var1 = var10000.intercept(this, CGLIB$hashCode$3$Method, CGLIB$emptyArgs, CGLIB$hashCode$3$Proxy);
return var1 == null ? 0 : ((Number)var1).intValue();
} else {
return super.hashCode();
}
}
final Object CGLIB$clone$4() throws CloneNotSupportedException {
return super.clone();
}
protected final Object clone() throws CloneNotSupportedException {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
return var10000 != null ? var10000.intercept(this, CGLIB$clone$4$Method, CGLIB$emptyArgs, CGLIB$clone$4$Proxy) : super.clone();
}
public static MethodProxy CGLIB$findMethodProxy(Signature var0) {
String var10000 = var0.toString();
switch(var10000.hashCode()) {
case -508378822:
if (var10000.equals("clone()Ljava/lang/Object;")) {
return CGLIB$clone$4$Proxy;
}
break;
case 371634473:
if (var10000.equals("call()Ljava/lang/String;")) {
return CGLIB$call$0$Proxy;
}
break;
case 1826985398:
if (var10000.equals("equals(Ljava/lang/Object;)Z")) {
return CGLIB$equals$1$Proxy;
}
break;
case 1913648695:
if (var10000.equals("toString()Ljava/lang/String;")) {
return CGLIB$toString$2$Proxy;
}
break;
case 1984935277:
if (var10000.equals("hashCode()I")) {
return CGLIB$hashCode$3$Proxy;
}
}
return null;
}
// 实例化构造方法会绑定CallBacks
public Dog$$EnhancerByCGLIB$$beb9d601() {
CGLIB$BIND_CALLBACKS(this);
}
// 设置CallBack到ThreadLocal
public static void CGLIB$SET_THREAD_CALLBACKS(Callback[] var0) {
CGLIB$THREAD_CALLBACKS.set(var0);
}
public static void CGLIB$SET_STATIC_CALLBACKS(Callback[] var0) {
CGLIB$STATIC_CALLBACKS = var0;
}
/**
* 判断并绑定CallBack对象【就是MethodInterceptor对象，也即自定义的CglibMethodInterceptor】
*/
private static final void CGLIB$BIND_CALLBACKS(Object var0) {
Dog$$EnhancerByCGLIB$$beb9d601 var1 = (Dog$$EnhancerByCGLIB$$beb9d601)var0;
if (!var1.CGLIB$BOUND) {
var1.CGLIB$BOUND = true;
Object var10000 = CGLIB$THREAD_CALLBACKS.get();
if (var10000 == null) {
var10000 = CGLIB$STATIC_CALLBACKS;
if (var10000 == null) {
return;
}
}
var1.CGLIB$CALLBACK_0 = (MethodInterceptor)((Callback[])var10000)[0];
}
}
/**
* 应用无参构造方法创立加强后的子类新实例
* @param callbacks 多个MethodInterceptor对象数组
* @return new instance of the same type
*/
public Object newInstance(Callback[] var1) {
CGLIB$SET_THREAD_CALLBACKS(var1);
Dog$$EnhancerByCGLIB$$beb9d601 var10000 = new Dog$$EnhancerByCGLIB$$beb9d601();
// 将ThreadLocal的 CallBacks 至空
CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
return var10000;
}
/**
* 应用无参构造方法创立加强后的子类新实例
* 该对象只能指定一个Callback【MethodInterceptor】
* @param callback 自定义的MethodInterceptor对象
* @return new instance of the same type
*/
public Object newInstance(Callback var1) {
CGLIB$SET_THREAD_CALLBACKS(new Callback[]{var1});
Dog$$EnhancerByCGLIB$$beb9d601 var10000 = new Dog$$EnhancerByCGLIB$$beb9d601();
CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
return var10000;
}
/** 本案例中，实例化增强子类的时候就是调用此办法
* @param types 构造方法参数类型
* @param args 构造方法参数
* @param callbacks 多个CallBack对象数组
* @return new instance of the same type
*/
public Object newInstance(Class[] var1, Object[] var2, Callback[] var3) {
CGLIB$SET_THREAD_CALLBACKS(var3);
Dog$$EnhancerByCGLIB$$beb9d601 var10000 = new Dog$$EnhancerByCGLIB$$beb9d601;
switch(var1.length) {
case 0:
var10000.<init>();
CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
return var10000;
default:
throw new IllegalArgumentException("Constructor not found");
}
}
public Callback getCallback(int var1) {
CGLIB$BIND_CALLBACKS(this);
MethodInterceptor var10000;
switch(var1) {
case 0:
var10000 = this.CGLIB$CALLBACK_0;
break;
default:
var10000 = null;
}
return var10000;
}
public void setCallback(int var1, Callback var2) {
switch(var1) {
case 0:
this.CGLIB$CALLBACK_0 = (MethodInterceptor)var2;
default:
}
}
public Callback[] getCallbacks() {
CGLIB$BIND_CALLBACKS(this);
return new Callback[]{this.CGLIB$CALLBACK_0};
}
public void setCallbacks(Callback[] var1) {
this.CGLIB$CALLBACK_0 = (MethodInterceptor)var1[0];
}
static {
CGLIB$STATICHOOK1();
}
}
（三）CGLIB生成的FastClass-1【简称f1】
Dog$$FastClassByCGLIB$$7ac19ed7
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//
package com.allen.testDynamicProxy.cglibProxy;
import java.lang.reflect.InvocationTargetException;
import net.sf.cglib.core.Signature;
import net.sf.cglib.reflect.FastClass;
public class Dog$$FastClassByCGLIB$$7ac19ed7 extends FastClass {
public Dog$$FastClassByCGLIB$$7ac19ed7(Class var1) {
super(var1);
}
public int getIndex(Signature var1) {
String var10000 = var1.toString();
switch(var10000.hashCode()) {
case 371634473:
if (var10000.equals("call()Ljava/lang/String;")) {
return 0;
}
break;
case 1826985398:
if (var10000.equals("equals(Ljava/lang/Object;)Z")) {
return 1;
}
break;
case 1913648695:
if (var10000.equals("toString()Ljava/lang/String;")) {
return 2;
}
break;
case 1984935277:
if (var10000.equals("hashCode()I")) {
return 3;
}
}
return -1;
}
public int getIndex(String var1, Class[] var2) {
switch(var1.hashCode()) {
case -1776922004:
if (var1.equals("toString")) {
switch(var2.length) {
case 0:
return 2;
}
}
break;
case -1295482945:
if (var1.equals("equals")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("java.lang.Object")) {
return 1;
}
}
}
break;
case 3045982:
if (var1.equals("call")) {
switch(var2.length) {
case 0:
return 0;
}
}
break;
case 147696667:
if (var1.equals("hashCode")) {
switch(var2.length) {
case 0:
return 3;
}
}
}
return -1;
}
public int getIndex(Class[] var1) {
switch(var1.length) {
case 0:
return 0;
default:
return -1;
}
}
public Object invoke(int var1, Object var2, Object[] var3) throws InvocationTargetException {
Dog var10000 = (Dog)var2;
int var10001 = var1;
try {
switch(var10001) {
case 0:
return var10000.call();
case 1:
return new Boolean(var10000.equals(var3[0]));
case 2:
return var10000.toString();
case 3:
return new Integer(var10000.hashCode());
}
} catch (Throwable var4) {
throw new InvocationTargetException(var4);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public Object newInstance(int var1, Object[] var2) throws InvocationTargetException {
Dog var10000 = new Dog;
Dog var10001 = var10000;
int var10002 = var1;
try {
switch(var10002) {
case 0:
var10001.<init>();
return var10000;
}
} catch (Throwable var3) {
throw new InvocationTargetException(var3);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public int getMaxIndex() {
return 3;
}
}
（四）CGLIB生成的FastClass-2【简称f2】
Dog$$EnhancerByCGLIB$$beb9d601$$FastClassByCGLIB$$916924fc
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//
package com.allen.testDynamicProxy.cglibProxy;
import com.allen.testDynamicProxy.cglibProxy.Dog..EnhancerByCGLIB..beb9d601;
import java.lang.reflect.InvocationTargetException;
import net.sf.cglib.core.Signature;
import net.sf.cglib.proxy.Callback;
import net.sf.cglib.reflect.FastClass;
public class Dog$$EnhancerByCGLIB$$beb9d601$$FastClassByCGLIB$$916924fc extends FastClass {
public Dog$$EnhancerByCGLIB$$beb9d601$$FastClassByCGLIB$$916924fc(Class var1) {
super(var1);
}
public int getIndex(Signature var1) {
String var10000 = var1.toString();
switch(var10000.hashCode()) {
case -2055565910:
if (var10000.equals("CGLIB$SET_THREAD_CALLBACKS([Lnet/sf/cglib/proxy/Callback;)V")) {
return 1;
}
break;
case -1882565338:
if (var10000.equals("CGLIB$equals$1(Ljava/lang/Object;)Z")) {
return 4;
}
break;
case -1457535688:
if (var10000.equals("CGLIB$STATICHOOK1()V")) {
return 8;
}
break;
case -1411842725:
if (var10000.equals("CGLIB$hashCode$3()I")) {
return 6;
}
break;
case -1212270792:
if (var10000.equals("CGLIB$call$0()Ljava/lang/String;")) {
return 5;
}
break;
case -894172689:
if (var10000.equals("newInstance(Lnet/sf/cglib/proxy/Callback;)Ljava/lang/Object;")) {
return 20;
}
break;
case -623122092:
if (var10000.equals("CGLIB$findMethodProxy(Lnet/sf/cglib/core/Signature;)Lnet/sf/cglib/proxy/MethodProxy;")) {
return 13;
}
break;
case -508378822:
if (var10000.equals("clone()Ljava/lang/Object;")) {
return 17;
}
break;
case -419626537:
if (var10000.equals("setCallbacks([Lnet/sf/cglib/proxy/Callback;)V")) {
return 9;
}
break;
case 371634473:
if (var10000.equals("call()Ljava/lang/String;")) {
return 2;
}
break;
case 560567118:
if (var10000.equals("setCallback(ILnet/sf/cglib/proxy/Callback;)V")) {
return 12;
}
break;
case 811063227:
if (var10000.equals("newInstance([Ljava/lang/Class;[Ljava/lang/Object;[Lnet/sf/cglib/proxy/Callback;)Ljava/lang/Object;")) {
return 19;
}
break;
case 973717575:
if (var10000.equals("getCallbacks()[Lnet/sf/cglib/proxy/Callback;")) {
return 11;
}
break;
case 1221173700:
if (var10000.equals("newInstance([Lnet/sf/cglib/proxy/Callback;)Ljava/lang/Object;")) {
return 18;
}
break;
case 1230699260:
if (var10000.equals("getCallback(I)Lnet/sf/cglib/proxy/Callback;")) {
return 10;
}
break;
case 1306468936:
if (var10000.equals("CGLIB$toString$2()Ljava/lang/String;")) {
return 3;
}
break;
case 1584330438:
if (var10000.equals("CGLIB$SET_STATIC_CALLBACKS([Lnet/sf/cglib/proxy/Callback;)V")) {
return 0;
}
break;
case 1800494055:
if (var10000.equals("CGLIB$clone$4()Ljava/lang/Object;")) {
return 7;
}
break;
case 1826985398:
if (var10000.equals("equals(Ljava/lang/Object;)Z")) {
return 14;
}
break;
case 1913648695:
if (var10000.equals("toString()Ljava/lang/String;")) {
return 15;
}
break;
case 1984935277:
if (var10000.equals("hashCode()I")) {
return 16;
}
}
return -1;
}
public int getIndex(String var1, Class[] var2) {
switch(var1.hashCode()) {
case -1776922004:
if (var1.equals("toString")) {
switch(var2.length) {
case 0:
return 15;
}
}
break;
case -1295482945:
if (var1.equals("equals")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("java.lang.Object")) {
return 14;
}
}
}
break;
case -1053468136:
if (var1.equals("getCallbacks")) {
switch(var2.length) {
case 0:
return 11;
}
}
break;
case -124978609:
if (var1.equals("CGLIB$equals$1")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("java.lang.Object")) {
return 4;
}
}
}
break;
case -60403779:
if (var1.equals("CGLIB$SET_STATIC_CALLBACKS")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("[Lnet.sf.cglib.proxy.Callback;")) {
return 0;
}
}
}
break;
case -29025555:
if (var1.equals("CGLIB$hashCode$3")) {
switch(var2.length) {
case 0:
return 6;
}
}
break;
case 3045982:
if (var1.equals("call")) {
switch(var2.length) {
case 0:
return 2;
}
}
break;
case 52714989:
if (var1.equals("CGLIB$call$0")) {
switch(var2.length) {
case 0:
return 5;
}
}
break;
case 85179481:
if (var1.equals("CGLIB$SET_THREAD_CALLBACKS")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("[Lnet.sf.cglib.proxy.Callback;")) {
return 1;
}
}
}
break;
case 94756189:
if (var1.equals("clone")) {
switch(var2.length) {
case 0:
return 17;
}
}
break;
case 147696667:
if (var1.equals("hashCode")) {
switch(var2.length) {
case 0:
return 16;
}
}
break;
case 161998109:
if (var1.equals("CGLIB$STATICHOOK1")) {
switch(var2.length) {
case 0:
return 8;
}
}
break;
case 495524492:
if (var1.equals("setCallbacks")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("[Lnet.sf.cglib.proxy.Callback;")) {
return 9;
}
}
}
break;
case 1154623345:
if (var1.equals("CGLIB$findMethodProxy")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("net.sf.cglib.core.Signature")) {
return 13;
}
}
}
break;
case 1543336189:
if (var1.equals("CGLIB$toString$2")) {
switch(var2.length) {
case 0:
return 3;
}
}
break;
case 1811874389:
if (var1.equals("newInstance")) {
switch(var2.length) {
case 1:
String var10001 = var2[0].getName();
switch(var10001.hashCode()) {
case -845341380:
if (var10001.equals("net.sf.cglib.proxy.Callback")) {
return 20;
}
break;
case 1730110032:
if (var10001.equals("[Lnet.sf.cglib.proxy.Callback;")) {
return 18;
}
}
case 2:
default:
break;
case 3:
if (var2[0].getName().equals("[Ljava.lang.Class;") && var2[1].getName().equals("[Ljava.lang.Object;") && var2[2].getName().equals("[Lnet.sf.cglib.proxy.Callback;")) {
return 19;
}
}
}
break;
case 1817099975:
if (var1.equals("setCallback")) {
switch(var2.length) {
case 2:
if (var2[0].getName().equals("int") && var2[1].getName().equals("net.sf.cglib.proxy.Callback")) {
return 12;
}
}
}
break;
case 1905679803:
if (var1.equals("getCallback")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("int")) {
return 10;
}
}
}
break;
case 1951977610:
if (var1.equals("CGLIB$clone$4")) {
switch(var2.length) {
case 0:
return 7;
}
}
}
return -1;
}
public int getIndex(Class[] var1) {
switch(var1.length) {
case 0:
return 0;
default:
return -1;
}
}
public Object invoke(int var1, Object var2, Object[] var3) throws InvocationTargetException {
beb9d601 var10000 = (beb9d601)var2;
int var10001 = var1;
try {
switch(var10001) {
case 0:
beb9d601.CGLIB$SET_STATIC_CALLBACKS((Callback[])var3[0]);
return null;
case 1:
beb9d601.CGLIB$SET_THREAD_CALLBACKS((Callback[])var3[0]);
return null;
case 2:
return var10000.call();
case 3:
return var10000.CGLIB$toString$2();
case 4:
return new Boolean(var10000.CGLIB$equals$1(var3[0]));
case 5:
return var10000.CGLIB$call$0();
case 6:
return new Integer(var10000.CGLIB$hashCode$3());
case 7:
return var10000.CGLIB$clone$4();
case 8:
beb9d601.CGLIB$STATICHOOK1();
return null;
case 9:
var10000.setCallbacks((Callback[])var3[0]);
return null;
case 10:
return var10000.getCallback(((Number)var3[0]).intValue());
case 11:
return var10000.getCallbacks();
case 12:
var10000.setCallback(((Number)var3[0]).intValue(), (Callback)var3[1]);
return null;
case 13:
return beb9d601.CGLIB$findMethodProxy((Signature)var3[0]);
case 14:
return new Boolean(var10000.equals(var3[0]));
case 15:
return var10000.toString();
case 16:
return new Integer(var10000.hashCode());
case 17:
return var10000.clone();
case 18:
return var10000.newInstance((Callback[])var3[0]);
case 19:
return var10000.newInstance((Class[])var3[0], (Object[])var3[1], (Callback[])var3[2]);
case 20:
return var10000.newInstance((Callback)var3[0]);
}
} catch (Throwable var4) {
throw new InvocationTargetException(var4);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public Object newInstance(int var1, Object[] var2) throws InvocationTargetException {
beb9d601 var10000 = new beb9d601;
beb9d601 var10001 = var10000;
int var10002 = var1;
try {
switch(var10002) {
case 0:
var10001.<init>();
return var10000;
}
} catch (Throwable var3) {
throw new InvocationTargetException(var3);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public int getMaxIndex() {
return 20;
}
}
三、CGLIB代理类创立流程
代理类的创立次要是在enhancer.create()办法调用后进行的，大抵流程如下：
（一）代理类的创立
首先看下在实例化代理类期间绑定Callback的过程「即自定义的MethodInterceptor」，外围源码【net.sf.cglib.proxy.Enhancer.EnhancerFactoryData#newInstance】：
留神这边的setThreadCallbacks是个final类型的变量，会在EnhancerFactoryData的构造方法中赋值为代理类Dog$$EnhancerByCGLIB$$beb9d601的SET_THREAD_CALLBACKS办法对象，对应的SET_THREAD_CALLBACKS源码如下：
// 设置CallBack到ThreadLocal
public static void CGLIB$SET_THREAD_CALLBACKS(Callback[] var0) {
// CGLIB$THREAD_CALLBACKS是个final static变量，在代理类的动态代码块中赋值为ThreadLocal()
// 代理类的动态代码块上面会讲到
CGLIB$THREAD_CALLBACKS.set(var0);
} 最初通过反射实例化代理类Dog$$EnhancerByCGLIB$$beb9d601的时候，会执行代理对象的静态方法块，期间会给每个被代理类Dog的成员办法创立一个MethdProxy代理办法对象。
（二）创立MethodProxy
MethodProxy封装了原始Dog类的办法签名【sig1】，对应代理类办法的签名【sig2】以及代理类的一些创立信息【原始类和代理类的名称、类生成策略等等】。对应的代理类的动态代码块内容如下：
// CGLIB$call$0$Method和CGLIB$call$0$Proxy就是MethodInterceptor接口的入参
static void CGLIB$STATICHOOK1() {
CGLIB$THREAD_CALLBACKS = new ThreadLocal();
CGLIB$emptyArgs = new Object[0];
// 加载生成的加强类
Class var0 = Class.forName("com.allen.testDynamicProxy.cglibProxy.Dog$$EnhancerByCGLIB$$beb9d601");
Class var1;
// 通过反射获取Object类的Method对象
Method[] var10000 = ReflectUtils.findMethods(new String[]{"equals", "(Ljava/lang/Object;)Z", "toString", "()Ljava/lang/String;", "hashCode", "()I", "clone", "()Ljava/lang/Object;"}, (var1 = Class.forName("java.lang.Object")).getDeclaredMethods());
CGLIB$equals$1$Method = var10000[0];
// 为 Method 创立对应的 MethodProxy 对象
CGLIB$equals$1$Proxy = MethodProxy.create(var1, var0, "(Ljava/lang/Object;)Z", "equals", "CGLIB$equals$1");
CGLIB$toString$2$Method = var10000[1];
CGLIB$toString$2$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/String;", "toString", "CGLIB$toString$2");
CGLIB$hashCode$3$Method = var10000[2];
CGLIB$hashCode$3$Proxy = MethodProxy.create(var1, var0, "()I", "hashCode", "CGLIB$hashCode$3");
CGLIB$clone$4$Method = var10000[3];
CGLIB$clone$4$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/Object;", "clone", "CGLIB$clone$4");
// Dog类call办法Method对象
CGLIB$call$0$Method = ReflectUtils.findMethods(new String[]{"call", "()Ljava/lang/String;"}, (var1 = Class.forName("com.allen.testDynamicProxy.cglibProxy.Dog")).getDeclaredMethods())[0];
// var1: 被代理类 var0：代理类
CGLIB$call$0$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/String;", "call", "CGLIB$call$0");
} 对应MethodProxy.create()【net.sf.cglib.proxy.MethodProxy#creat()】办法：
/**
* For internal use by {@link Enhancer} only; see the {@link net.sf.cglib.reflect.FastMethod} class
* for similar functionality.
* @param c1 被代理类
* @param c2 代理类
* @param desc 办法形容【"()Ljava/lang/String;"】
* @param name1 办法1名称【"call"】
* @param name2 办法2名称【"CGLIB$call$0"】
*/
public static MethodProxy create(Class c1, Class c2, String desc, String name1, String name2) {
MethodProxy proxy = new MethodProxy();
// 构建办法签名
proxy.sig1 = new Signature(name1, desc);
proxy.sig2 = new Signature(name2, desc);
proxy.createInfo = new CreateInfo(c1, c2);
return proxy;
}对于办法签名的debug信息【前面会用这个办法签名在Fastclass中查问对应的index索引】：
（三）创立CreateInfo
CreateInfo是MethodProxy的一个外部类，次要保留代理类的一些创立信息。
private static class CreateInfo
{
// 对应Dog原始类
Class c1;
// 代理类Dog$$EnhancerByCGLIB$$beb9d601
Class c2;
// 代理类命名策略
NamingPolicy namingPolicy;
// 代理类生成策略
GeneratorStrategy strategy;
boolean attemptLoad;
public CreateInfo(Class c1, Class c2)
{
this.c1 = c1;
this.c2 = c2;
AbstractClassGenerator fromEnhancer = AbstractClassGenerator.getCurrent();
if (fromEnhancer != null) {
namingPolicy = fromEnhancer.getNamingPolicy();
strategy = fromEnhancer.getStrategy();
attemptLoad = fromEnhancer.getAttemptLoad();
}
}
}四、CGLIB动静代理调用流程
当执行指标办法时，代理对象调用流程如下：
置信看完下面的流程图，根本就对CGLIB的底层实现有了大抵的概念。当然上面我还会进行详细分析。
（一）重写父类办法
基于一开始的demo，笔者从调用指标办法一步步剖析。⚠️main办法调用poolDog.call();时，实际上执行的是代理对象的call()办法，代理对象的生成曾经在上一节剖析过了。那咱们间接看代理对象的call()办法，源码如下：
/**
* 重写 Dog类的call办法，增加CallBack回调
* 【即执行MethodInterceptor的intercept办法，即咱们自定义的 CglibMethodInterceptor的intercept办法】
*/
public final String call() {
// 从成员属性CGLIB$CALLBACK_0获取MethodInterceptor
// 第一次调用是null，进入上面的if逻辑
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
// 从新绑定MethodInterceptor，并赋值给成员属性CGLIB$CALLBACK_0
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
// @param this 代理对象自身
// @param CGLIB$call$0$Method Dog类call办法Method对象【动态代码块已赋值】
// @param CGLIB$emptyArgs Dog类call办法参数【我这边是void，所以没有】
// @param CGLIB$call$0$Proxy Dog类call办法的代理办法对象【动态代码块已赋值】
return var10000 != null ? (String)var10000.intercept(this, CGLIB$call$0$Method, CGLIB$emptyArgs, CGLIB$call$0$Proxy) : super.call();
}
/**
* 判断并绑定CallBack对象【就是MethodInterceptor对象，也即自定义的CglibMethodInterceptor】
*/
private static final void CGLIB$BIND_CALLBACKS(Object var0) {
// var0即代理类以后对象，将其对象的援用指向var1
Dog$$EnhancerByCGLIB$$beb9d601 var1 = (Dog$$EnhancerByCGLIB$$beb9d601)var0;
// 这边判断是true，创立代理类的时候通过反射已将对应的Callback设置到ThreadLocal
if (!var1.CGLIB$BOUND) {
var1.CGLIB$BOUND = true;
// 将ThreadLocal中的Callback赋值给var10000
Object var10000 = CGLIB$THREAD_CALLBACKS.get();
if (var10000 == null) {
var10000 = CGLIB$STATIC_CALLBACKS;
if (var10000 == null) {
return;
}
}
// 将Callback赋值给成员属性CGLIB$CALLBACK_0
var1.CGLIB$CALLBACK_0 = (MethodInterceptor)((Callback[])var10000)[0];
}
}当调用代理对象重写过的call()办法时，会执行对应的办法拦截器，即咱们自定义的MethodInterceptor中intercept办法的逻辑【本案例中对应自定义拦截器类CglibMethodInterceptor】，对应intercept办法的传参和含意在下面的代码正文中已阐明。
（二）原始父类办法的匹配调用
接下来，在MethodInterceptor的intercept办法中调用的methodProxy.invokeSuper(object, args);时，最终就会执行父类Dog的call()办法。具体怎么调用执行的，先看MethodProxy.invokeSuper(object, args);的执行逻辑，源码如下：
/**
* 调用CGLIB加强的父类指标办法
* @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 {
// 初始化辅助数据
init();
FastClassInfo fci = fastClassInfo;
return fci.f2.invoke(fci.i2, obj, args);
} catch (InvocationTargetException e) {
throw e.getTargetException();
}
}1. init()办法
在下面的流程图中咱们也大抵能看到init()办法干了些什么事。次要是在解决FastClass，FastClass是什么？
简略了解，FastClass是代理对象办法 到 被代理对象办法的映射【对应FastClass的源码已在前置筹备中贴出】。
1）先看下init()办法源码：
private void init()
{
/*
* Using a volatile invariant allows us to initialize the FastClass and
* method index pairs atomically.
*
* Double-checked locking is safe with volatile in Java 5. Before 1.5 this
* code could allow fastClassInfo to be instantiated more than once, which
* appears to be benign.
*/
if (fastClassInfo == null)
{
synchronized (initLock)
{
if (fastClassInfo == null)
{
// 获取代理类的创立信息【下面有提过】
CreateInfo ci = createInfo;
// 新建FastClassInfo对象
FastClassInfo fci = new FastClassInfo();
// 生成FastClass f1，并赋值给FastClassInfo的成员属性
fci.f1 = helper(ci, ci.c1);
fci.f2 = helper(ci, ci.c2);
// 依据办法签名，获取代理类中对应call办法在f1中的索引
fci.i1 = fci.f1.getIndex(sig1);
// 依据办法签名，获取代理类中对应call办法在f2中的索引
fci.i2 = fci.f2.getIndex(sig2);
fastClassInfo = fci;
createInfo = null;
}
}
}
}
/*
* FastClassInfo也是MethodProxy的一个外部类
*/
private static class FastClassInfo
{
// 对应前置筹备中的f1
FastClass f1;
// 对应前置筹备中的f2
FastClass f2;
int i1;
int i2;
}init()办法其实就是创立了两个FastClass，而后建设FastClass 到 代理对象 对于 指标办法 的 索引。
2）fci.f2.invoke(fci.i2, obj, args)；
invoke的传参阐明：
- i2: 获取代理类中对应call办法在f2中的索引
- obj: 代理对象自身
- args: 指标办法的传参
f2中invoke局部源码：
接下就会调用代理对象对应的办法：
看到这是不是有点明了了，最初这不就是执行了咱们父类Dog的call()办法吗。那整个外围的实现逻辑和调用流程大抵就是这样的。
（三）CGLIB死循环了
下面一大节对于指标办法的调用是通过net.sf.cglib.proxy.MethodProxy#invokeSuper实现的，CGLIB中还有一个net.sf.cglib.proxy.MethodProxy#invoke。在自定义的MethodProxy中，将invokeSuper改成invoke，运行一下，报错了，有限递归导致栈溢出。
在解释起因之前，有没有发现一个问题，后面不是生成了两个FastClass吗，截止当初咱们只用到了一个。你的猜测正确，invoke办法就是用的f1中的索引。
死循话的问题我这边不具体解释，以一张图阐明【其中的元素信息齐全基于前置筹备的代码，同学们能够本人本地写个demo尝试】：
五、性能：CGLIB vs JDK
其实说实话，工作中并没有说单单就因为将动静代理模式从JDK换成CGLIB，性能就有显著晋升的状况，大部分状况性能相差不多。然而显著CGLIB适用性更广，SpringBoot将AOP的动静代理默认设置成了CGLIB，我想预计也不是性能使然。
实践上说，针对JDK动静代理的Method.invoke()和CGLIB的MethodProxy.invokeSuper()这两个invoke来说，CGLIB感觉更加优雅些，然而刚开始第一次调用CGLIB是比较慢的，还记得下面提到的init()吗。非要钻牛角尖说CGLIB性能更好的话，可能是MethodAccessor的锅。
Method.invoke(target,params)，理论是MethodAccessor实例真正实现反射调用。Java 版本的MethodAccessorImpl调用效率比Native版本要快 20 倍以上，然而 Java 版本加载时要比 Native 多耗费 3-4 倍资源，所以默认会调用 Native 版本，如果调用次数超过 15 次当前，就会抉择运行效率更高的 Java 版本。然而⚠️：寄存method的reflectionData是SoftReference的，即在某些内存比拟刻薄的状况下是可能被回收的【通过-XX:SoftRefLRUPolicyMSPerMB这个参数来管制回收的机会】。一旦回收，就须要调用getDeclaredMethods0进行遍历查找，从新缓存。
对于JDK代理的细节，能够参考我之前的文章：https://www.heapdump.cn/artic…
over，心愿这篇吐血肝货，能够帮你了解CGLIB底层实现原理。持续肝💪·····
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