CGlib与JDK动态代理

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1 实现两种动态代理

1.1 JDK代理

JDK动态代理只能对接口实现代理
定义一个接口

public interface  Service {    public abstract void say();}

实现接口

public class ServiceImpl implements Service {    @Override    public void say() {        System.out.println("Hello JDK");    }}

实现InvocationHandler

public class JDKInvocationHandler implements InvocationHandler {    // 目标对象    private Object target;    /**     * 构造方法     * @param target 目标对象     */    public JDKInvocationHandler(Object target) {        super();        this.target = target;    }    @Override    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {        // 在目标对象的方法执行之前简单的打印一下        System.out.println("------------------before------------------");        // 执行目标对象的方法        Object result = method.invoke(target, args);        // 在目标对象的方法执行之后简单的打印一下        System.out.println("-------------------after------------------");        return result;    }    public Object getProxy() {        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),                target.getClass().getInterfaces(), this);    }}

测试类

public class TestJDKProxy {    public static void main(String[] a) {        // 实例化目标对象        Service userService = new ServiceImpl();        // 实例化InvocationHandler        JDKInvocationHandler invocationHandler = new JDKInvocationHandler(userService);        // 根据目标对象生成代理对象        Service proxy = (Service) invocationHandler.getProxy();        // 调用代理对象的方法        proxy.say();        //将生成的代理类写到E盘        writeProxyClassToHardDisk("E:/$Proxy11.class");    }        public static void writeProxyClassToHardDisk(String path) {        byte[] classFile = ProxyGenerator.generateProxyClass("$Proxy11", ServiceImpl.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();            }        }    }}

1.2 CGlib代理

CGlib动态代理需要cglib的jar包
maven引入

    <dependency>      <groupId>cglib</groupId>      <artifactId>cglib</artifactId>      <version>3.1</version>    </dependency>

定义一个被代理类

public class SomeClass {    public void doSomething() {        System.out.println("方法正在执行...");    }}

实现cglib的MethodInterceptor

public class CGlibProxy implements MethodInterceptor {    private Object target;    public Object getInstance(Object target) {        this.target = target;        Enhancer enhancer = new Enhancer();        enhancer.setSuperclass(this.target.getClass());        enhancer.setCallback(this);        return enhancer.create();    }    @Override    public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {        System.out.println("..........before..........");        proxy.invokeSuper(obj, args);        System.out.println("..........after ..........");        return null;    }}

测试类

public class TestCGlib {    public static void main(String[] a) throws Exception {        //输出生成的代理类class文件到指定的目录        System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "E:\\cglib");        CGlibProxy cglib = new CGlibProxy();        SomeClass businessObject = (SomeClass) cglib.getInstance(new SomeClass());//        System.out.println(businessObject.getClass().getName());//        System.out.println(businessObject.getClass().getSuperclass().getName());        businessObject.doSomething();    }}

2 代理生成的代理类解析

2.1 JDK代理类

import com.lww.learnjdk.JDKProxy.Service;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.lang.reflect.UndeclaredThrowableException;//看到这就明白为什么JDK只能代理接口了//JDK动态代理自己就得继承Proxy类，而Java只能单继承public final class $Proxy11  extends Proxy  implements Service{  private static Method m1;  private static Method m2;  private static Method m3;  private static Method m0;  public $Proxy11(InvocationHandler paramInvocationHandler)    throws   {    super(paramInvocationHandler);  }  public final boolean equals(Object paramObject)    throws   {    try    {      return ((Boolean)this.h.invoke(this, m1, new Object[] { paramObject })).booleanValue();    }    catch (Error|RuntimeException localError)    {      throw localError;    }    catch (Throwable localThrowable)    {      throw new UndeclaredThrowableException(localThrowable);    }  }  public final String toString()    throws   {    try    {      return (String)this.h.invoke(this, m2, null);    }    catch (Error|RuntimeException localError)    {      throw localError;    }    catch (Throwable localThrowable)    {      throw new UndeclaredThrowableException(localThrowable);    }  }  public final void say()    throws   {    try    {    //m3通过Java反射调用被代理接口的say方法      this.h.invoke(this, m3, null);      return;    }    catch (Error|RuntimeException localError)    {      throw localError;    }    catch (Throwable localThrowable)    {      throw new UndeclaredThrowableException(localThrowable);    }  }  public final int hashCode()    throws   {    try    {      return ((Integer)this.h.invoke(this, m0, null)).intValue();    }    catch (Error|RuntimeException localError)    {      throw localError;    }    catch (Throwable localThrowable)    {      throw new UndeclaredThrowableException(localThrowable);    }  }  static  {    try    {      m1 = Class.forName("java.lang.Object").getMethod("equals", new Class[] { Class.forName("java.lang.Object") });      m2 = Class.forName("java.lang.Object").getMethod("toString", new Class[0]);      m3 = Class.forName("com.lww.learnjdk.JDKProxy.Service").getMethod("say", new Class[0]);      m0 = Class.forName("java.lang.Object").getMethod("hashCode", new Class[0]);      return;    }    catch (NoSuchMethodException localNoSuchMethodException)    {      throw new NoSuchMethodError(localNoSuchMethodException.getMessage());    }    catch (ClassNotFoundException localClassNotFoundException)    {      throw new NoClassDefFoundError(localClassNotFoundException.getMessage());    }  }}

2.2 CGlib代理类

生成的Class源码，使用jd-gui查看
使用jd-gui查看可能会出现反编译不全的情况。我后面使用procyon-decompiler-0.5.30.jar反编译的
jar地址https://bitbucket.org/mstrobel/procyon/downloads/
命令java -jar procyon-decompiler-0.5.30.jar SomeClass$$EnhancerByCGLIB$.$84389373.class
去掉一个两个$中间的.因为编辑器的原因加上的

package com.lww.learnjdk.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;public class SomeClass$$EnhancerByCGLIB$$84389373  extends SomeClass  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$doSomething$0$Method;  private static final MethodProxy CGLIB$doSomething$0$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];    Class localClass1 = Class.forName("com.lww.learnjdk.CGlibProxy.SomeClass$$EnhancerByCGLIB$$84389373");    Class localClass2;    Method[] tmp95_92 = ReflectUtils.findMethods(new String[] { "finalize", "()V", "equals", "(Ljava/lang/Object;)Z", "toString", "()Ljava/lang/String;", "hashCode", "()I", "clone", "()Ljava/lang/Object;" }, (localClass2 = Class.forName("java.lang.Object")).getDeclaredMethods());    CGLIB$finalize$1$Method = tmp95_92[0];    CGLIB$finalize$1$Proxy = MethodProxy.create(localClass2, localClass1, "()V", "finalize", "CGLIB$finalize$1");    Method[] tmp115_95 = tmp95_92;    CGLIB$equals$2$Method = tmp115_95[1];    CGLIB$equals$2$Proxy = MethodProxy.create(localClass2, localClass1, "(Ljava/lang/Object;)Z", "equals", "CGLIB$equals$2");    Method[] tmp135_115 = tmp115_95;    CGLIB$toString$3$Method = tmp135_115[2];    CGLIB$toString$3$Proxy = MethodProxy.create(localClass2, localClass1, "()Ljava/lang/String;", "toString", "CGLIB$toString$3");    Method[] tmp155_135 = tmp135_115;    CGLIB$hashCode$4$Method = tmp155_135[3];    CGLIB$hashCode$4$Proxy = MethodProxy.create(localClass2, localClass1, "()I", "hashCode", "CGLIB$hashCode$4");    Method[] tmp175_155 = tmp155_135;    CGLIB$clone$5$Method = tmp175_155[4];    CGLIB$clone$5$Proxy = MethodProxy.create(localClass2, localClass1, "()Ljava/lang/Object;", "clone", "CGLIB$clone$5");    tmp175_155;    Method[] tmp223_220 = ReflectUtils.findMethods(new String[] { "doSomething", "()V" }, (localClass2 = Class.forName("com.lww.learnjdk.CGlibProxy.SomeClass")).getDeclaredMethods());    CGLIB$doSomething$0$Method = tmp223_220[0];    CGLIB$doSomething$0$Proxy = MethodProxy.create(localClass2, localClass1, "()V", "doSomething", "CGLIB$doSomething$0");    tmp223_220;    return;  }  //调用父类方法  //在后面会用到  //千万要记得这个方法    final void CGLIB$doSomething$0() {        super.doSomething();    }       public final void doSomething() {        MethodInterceptor cglib$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$CALLBACK_0 != null) {        //调用你实现MethodInterceptor的intercept方法            cglib$CALLBACK_2.intercept((Object)this, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$doSomething$0$Method, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$emptyArgs, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$doSomething$0$Proxy);            return;        }        super.doSomething();    }    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, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$finalize$1$Method, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$emptyArgs, SomeClass$$EnhancerByCGLIB$$84389373.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, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$equals$2$Method, new Object[] { o }, SomeClass$$EnhancerByCGLIB$$84389373.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, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$toString$3$Method, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$emptyArgs, SomeClass$$EnhancerByCGLIB$$84389373.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, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$hashCode$4$Method, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$emptyArgs, SomeClass$$EnhancerByCGLIB$$84389373.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, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$clone$5$Method, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$emptyArgs, SomeClass$$EnhancerByCGLIB$$84389373.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 SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$finalize$1$Proxy;                }                break;            }            case -508378822: {                if (string.equals("clone()Ljava/lang/Object;")) {                    return SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$clone$5$Proxy;                }                break;            }            case 1826985398: {                if (string.equals("equals(Ljava/lang/Object;)Z")) {                    return SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$equals$2$Proxy;                }                break;            }            case 1913648695: {                if (string.equals("toString()Ljava/lang/String;")) {                    return SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$toString$3$Proxy;                }                break;            }            case 1984935277: {                if (string.equals("hashCode()I")) {                    return SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$hashCode$4$Proxy;                }                break;            }            case 2121560294: {                if (string.equals("doSomething()V")) {                    return SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$doSomething$0$Proxy;                }                break;            }        }        return null;    }    public SomeClass$$EnhancerByCGLIB$$84389373() {        CGLIB$BIND_CALLBACKS(this);    }    public static void CGLIB$SET_THREAD_CALLBACKS(final Callback[] array) {        SomeClass$$EnhancerByCGLIB$$84389373.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 SomeClass$$EnhancerByCGLIB$$84389373 someClass$$EnhancerByCGLIB$$84389373 = (SomeClass$$EnhancerByCGLIB$$84389373)o;        if (!someClass$$EnhancerByCGLIB$$84389373.CGLIB$BOUND) {            someClass$$EnhancerByCGLIB$$84389373.CGLIB$BOUND = true;            Object o2;            if ((o2 = SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$THREAD_CALLBACKS.get()) != null || (o2 = SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$STATIC_CALLBACKS) != null) {                someClass$$EnhancerByCGLIB$$84389373.CGLIB$CALLBACK_0 = (MethodInterceptor)((Callback[])o2)[0];            }        }    }    public Object newInstance(final Callback[] array) {        CGLIB$SET_THREAD_CALLBACKS(array);        final SomeClass$$EnhancerByCGLIB$$84389373 someClass$$EnhancerByCGLIB$$84389373 = new SomeClass$$EnhancerByCGLIB$$84389373();        CGLIB$SET_THREAD_CALLBACKS(null);        return someClass$$EnhancerByCGLIB$$84389373;    }    public Object newInstance(final Callback callback) {        CGLIB$SET_THREAD_CALLBACKS(new Callback[] { callback });        final SomeClass$$EnhancerByCGLIB$$84389373 someClass$$EnhancerByCGLIB$$84389373 = new SomeClass$$EnhancerByCGLIB$$84389373();        CGLIB$SET_THREAD_CALLBACKS(null);        return someClass$$EnhancerByCGLIB$$84389373;    }    public Object newInstance(final Class[] array, final Object[] array2, finalCallback[] array3) {        CGLIB$SET_THREAD_CALLBACKS(array3);        switch (array.length) {            case 0: {                final SomeClass$$EnhancerByCGLIB$$84389373 someClass$$EnhancerByCGLIB$$84389373 = new SomeClass$$EnhancerByCGLIB$$84389373();                CGLIB$SET_THREAD_CALLBACKS(null);                return someClass$$EnhancerByCGLIB$$84389373;            }            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();    }}

3 两种方式解析

前面已经知道怎么实现，看了完整的源码。现在看怎么实现以及调用过程

3.1 CGlib代理解析

1、创建
在TestCGlib调用CGlibProxy的getInstance方法

        SomeClass businessObject = (SomeClass) cglib.getInstance(new SomeClass());

CGlibProxy的getInstance方法

    public Object getInstance(Object target) {        this.target = target;        Enhancer enhancer = new Enhancer();        //设置父类        enhancer.setSuperclass(this.target.getClass());        //用来生成的代理类回调intercept()方法        //在生成的代理类源码有判断        enhancer.setCallback(this);        //主要        return enhancer.create();    }

Enhancer的create方法

    public Object create() {        this.classOnly = false;        this.argumentTypes = null;        return this.createHelper();    }

Enhancer的createHelper方法

    private Object createHelper() {        this.validate();        if(this.superclass != null) {            this.setNamePrefix(this.superclass.getName());        } else if(this.interfaces != null) {            this.setNamePrefix(this.interfaces[ReflectUtils.findPackageProtected(this.interfaces)].getName());        }        //调用父类AbstractClassGenerator生成代理类        return super.create(KEY_FACTORY.newInstance(this.superclass != null?this.superclass.getName():null, ReflectUtils.getNames(this.interfaces), this.filter, this.callbackTypes, this.useFactory, this.interceptDuringConstruction, this.serialVersionUID));    }

具体怎么生成我也看不太懂<.-.>
2、调用
在TestCGlib中

//此处businessObject已经是代理类了businessObject.doSomething();

代理类的doSomething方法查看源码

    public final void doSomething() {        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) {        //调用CGlibProxy的intercept方法        //参数1、代理对象；2、委托类方法；3、方法参数；4、代理方法的MethodProxy对象。            cglib$CALLBACK_2.intercept((Object)this, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$doSomething$0$Method, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$emptyArgs, SomeClass$$EnhancerByCGLIB$$84389373.CGLIB$doSomething$0$Proxy);            return;        }        super.doSomething();    }

CGlibProxy的intercept方法

    @Override    public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {    //这里只是调用输出的前后消息并没有执行被调类的方法        System.out.println("..........before..........");        //进入这个函数        proxy.invokeSuper(obj, args);        System.out.println("..........after ..........");        return null;    }

MethodProxy的invokeSuper方法

//这里面就是关键    public Object invokeSuper(Object obj, Object[] args) throws Throwable {        try {            this.init();            MethodProxy.FastClassInfo fci = this.fastClassInfo;            //f2是由CGlib生成的在输出的class中有            //SomeClass$$EnhancerByCGLIB$$831e1f52$$FastClassByCGLIB$$513605b2.class            return fci.f2.invoke(fci.i2, obj, args);        } catch (InvocationTargetException var4) {            throw var4.getTargetException();        }    }

查看f2.invoke方法

    public Object invoke(final int n, final Object o, final Object[] array) throws InvocationTargetException {        final SomeClass$$EnhancerByCGLIB$$831e1f52 someClass$$EnhancerByCGLIB$$831e1f52 = (SomeClass$$EnhancerByCGLIB$$831e1f52)o;        try {            switch (n) {                case 0: {                    return new Boolean(someClass$$EnhancerByCGLIB$$831e1f52.equals(array[0]));                }                case 1: {                    return someClass$$EnhancerByCGLIB$$831e1f52.toString();                }                case 2: {                    return new Integer(someClass$$EnhancerByCGLIB$$831e1f52.hashCode());                }                case 3: {                    return someClass$$EnhancerByCGLIB$$831e1f52.newInstance((Class[])array[0], (Object[])array[1], (Callback[])array[2]);                }                case 4: {                    return someClass$$EnhancerByCGLIB$$831e1f52.newInstance((Callback)array[0]);                }                case 5: {                    return someClass$$EnhancerByCGLIB$$831e1f52.newInstance((Callback[])array[0]);                }                case 6: {                    someClass$$EnhancerByCGLIB$$831e1f52.setCallbacks((Callback[])array[0]);                    return null;                }                case 7: {                    someClass$$EnhancerByCGLIB$$831e1f52.setCallback(((Number)array[0]).intValue(), (Callback)array[1]);                    return null;                }                case 8: {                    someClass$$EnhancerByCGLIB$$831e1f52.doSomething();                    return null;                }                case 9: {                    return someClass$$EnhancerByCGLIB$$831e1f52.getCallback(((Number)array[0]).intValue());                }                case 10: {                    return someClass$$EnhancerByCGLIB$$831e1f52.getCallbacks();                }                case 11: {                    SomeClass$$EnhancerByCGLIB$$831e1f52.CGLIB$SET_STATIC_CALLBACKS((Callback[])array[0]);                    return null;                }                case 12: {                    SomeClass$$EnhancerByCGLIB$$831e1f52.CGLIB$SET_THREAD_CALLBACKS((Callback[])array[0]);                    return null;                }                case 13: {                    return new Boolean(someClass$$EnhancerByCGLIB$$831e1f52.CGLIB$equals$2(array[0]));                }                case 14: {                    someClass$$EnhancerByCGLIB$$831e1f52.CGLIB$finalize$1();                    return null;                }                case 15: {                    return someClass$$EnhancerByCGLIB$$831e1f52.CGLIB$toString$3();                }                case 16: {                    return new Integer(someClass$$EnhancerByCGLIB$$831e1f52.CGLIB$hashCode$4());                }                case 17: {                    return someClass$$EnhancerByCGLIB$$831e1f52.CGLIB$clone$5();                }                case 18: {                    return SomeClass$$EnhancerByCGLIB$$831e1f52.CGLIB$findMethodProxy((Signature)array[0]);                }                case 19: {                    SomeClass$$EnhancerByCGLIB$$831e1f52.CGLIB$STATICHOOK1();                    return null;                }                case 20: {                //看到这doSomething$0方法是不是很惊喜。没错就是调用父类doSomething。                //前面的一串someClass$$EnhancerByCGLIB$$831e1f52是CGlib生成的代理类                //那么会不会走这个方法呢。我们调试就知道了，记住case 20！！！                    someClass$$EnhancerByCGLIB$$831e1f52.CGLIB$doSomething$0();                    return null;                }                case 21: {                    someClass$$EnhancerByCGLIB$$831e1f52.wait();                    return null;                }                case 22: {                    someClass$$EnhancerByCGLIB$$831e1f52.wait(((Number)array[0]).longValue(), ((Number)array[1]).intValue());                    return null;                }                case 23: {                    someClass$$EnhancerByCGLIB$$831e1f52.wait(((Number)array[0]).longValue());                    return null;                }                case 24: {                    return someClass$$EnhancerByCGLIB$$831e1f52.getClass();                }                case 25: {                    someClass$$EnhancerByCGLIB$$831e1f52.notify();                    return null;                }                case 26: {                    someClass$$EnhancerByCGLIB$$831e1f52.notifyAll();                    return null;                }            }        }        catch (Throwable t) {            throw new InvocationTargetException(t);        }        throw new IllegalArgumentException("Cannot find matching method/constructor");    }

我们看到直接就是20。
进入case 20调用父类的方法，然后就返回到CGlibProxy的intercept方法，因为还有最后一句after没有输出啊！

    @Override    public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {        System.out.println("..........before..........");        proxy.invokeSuper(obj, args);        System.out.println("..........after ..........");        return null;    }

最后就结束了！

3.2 JDK动态代理解析

1、生成代理类
TestJDKProxy

        // 实例化目标对象        Service userService = new ServiceImpl();        // 实例化InvocationHandler        JDKInvocationHandler invocationHandler = new JDKInvocationHandler(userService);        // 根据目标对象生成代理对象        Service proxy = (Service) invocationHandler.getProxy();

跟入getProxy方法(JDKInvocationHandler类)

    public Object getProxy() {        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),                target.getClass().getInterfaces(), this);    }

生成部分还是等我看懂了，再来补充吧
2、调用
TestJDKProxy中

    // 已经是代理类了        // 调用代理对象的方法        proxy.say();

查看代理类

  public final void say()    throws   {    try    {      this.h.invoke(this, m3, null);      return;    }    catch (Error|RuntimeException localError)    {      throw localError;    }    catch (Throwable localThrowable)    {      throw new UndeclaredThrowableException(localThrowable);    }  }//在静态方法执行的。m3 = Class.forName("com.lww.learnjdk.JDKProxy.Service").getMethod("say", new Class[0]);

回到JDKInvocationHandler类查看invoke方法

    @Override    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {        System.out.println("------------------before------------------");        Object result = method.invoke(target, args);        System.out.println("-------------------after------------------");        return result;    }

Method的invoke方法
到这再往下就是java反射（方法）的源码了

    public Object invoke(Object obj, Object... args)        throws IllegalAccessException, IllegalArgumentException,           InvocationTargetException    {        if (!override) {            if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) {                Class<?> caller = Reflection.getCallerClass();                checkAccess(caller, clazz, obj, modifiers);            }        }        MethodAccessor ma = methodAccessor;             // read volatile        if (ma == null) {            ma = acquireMethodAccessor();        }        //执行这句        return ma.invoke(obj, args);    }

MethodAccessor 类继承结构图
继承图
具体执行方法是 DelegatingMethodAccessorImpl

    private MethodAccessorImpl delegate;    public Object invoke(Object var1, Object[] var2) throws IllegalArgumentException, InvocationTargetException {        return this.delegate.invoke(var1, var2);    }

NativeMethodAccessorImpl的invoke方法

    public Object invoke(Object var1, Object[] var2) throws IllegalArgumentException, InvocationTargetException {        if(++this.numInvocations > ReflectionFactory.inflationThreshold() && !ReflectUtil.isVMAnonymousClass(this.method.getDeclaringClass())) {            MethodAccessorImpl var3 = (MethodAccessorImpl)(new MethodAccessorGenerator()).generateMethod(this.method.getDeclaringClass(), this.method.getName(), this.method.getParameterTypes(), this.method.getReturnType(), this.method.getExceptionTypes(), this.method.getModifiers());            this.parent.setDelegate(var3);        }        //调用本地方法        return invoke0(this.method, var1, var2);    }    //本地方法执行方法        private static native Object invoke0(Method var0, Object var1, Object[] var2);

调用ServiceImpl的say方法

    @Override    public void say() {        System.out.println("Hello JDK");    }

4 总结

4.1 JDK动态代理

1、生成代理类快，因为方法调用交给Java反射做了
2、只能面向接口，因为代理类默认继承Proxy类
3、不需要其他jar包

4.2 CGlib动态代理

优点：
1、执行速度快，因为CGlib生成代理类的时候会将被代理类的方法进行编号，直接传入编号就调用了。
2、可以为没有接口的类进行动态代理
劣势：
1、就因为它要编号所以它生成代理类的速度比较慢。尤其是需要多次生成代理类的时候。
2、因为是继承关系所以如果父类的final方法它就无能为力了

5 补充

参考资料：
http://blog.csdn.net/tiandesheng111/article/details/39833901
http://www.cnblogs.com/chinajava/p/5880870.html
http://www.cnblogs.com/chinajava/p/5880887.html

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