cglib动态代理

Posted NCS123456

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前面介绍了代理模式和JAVA动态代理,这片文章主要解析cglib动态代理实现。

基本介绍

CGLIB(Code Generation Library),是一个强大的,高性能,高质量的 Code 生成类库,它可以在运行期扩展 Java 类与实现 Java 接口。

pom

        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.2.7</version>
        </dependency>

cglib案例

目标类

public interface UserService 

    public void say();

    public void say2();



public class UserServiceImpl implements UserService

    @Override
    public void say() 
        System.out.println("hello");
        say2();
    

    @Override
    public void say2() 
        System.out.println("hello2");
    

    public final void finalMethod() 
        System.out.println("final method");
    

    public static void staticMethod() 
        System.out.println("static method");
    

方法拦截器

MethodInterceptor类似于jdk动态代理的InvocationHandler,方法调用前后进行增强。
public class MyInterceptor implements MethodInterceptor 

    private Object target;

    public MyInterceptor(Object target) 
        this.target = target;
    

    /**
     *
     * @param o 代理对象
     * @param method 被代理对象的方法
     * @param objects 方法入参
     * @param methodProxy 代理方法
     * @return
     * @throws Throwable
     */
    @Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable 
        System.out.println("cglib before");
        // 调用代理类FastClass对象
        Object result =  methodProxy.invokeSuper(o, objects);
//        Object result = methodProxy.invoke(target, objects);
        System.out.println("cglib after");
        return result;
    

客户端

public class CglibClient 

    public static void main(String[] args) 
        UserServiceImpl target = new UserServiceImpl();

        // 代理类class文件存入本地磁盘方便我们反编译查看源码
        System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "./code");
        // 通过CGLIB动态代理获取代理对象的过程
        Enhancer enhancer = new Enhancer();
        // 设置enhancer对象的父类
        enhancer.setSuperclass(UserServiceImpl.class);
        // 设置enhancer的回调对象
        enhancer.setCallback(new MyInterceptor(target));
        // 创建代理对象
        UserServiceImpl userService = (UserServiceImpl)enhancer.create();
        // 通过代理对象调用目标方法
        userService.say();
        userService.finalMethod();
        UserServiceImpl.staticMethod();
    

输出结果

cglib before
hello
cglib before
hello2
cglib after
cglib after
final method
static method

打印结果显示,final,static等方法不会代码增强,say()方法内部调用say2(),say2()方法也会进行增强。具体原因后面代理类字节码反编译解释。

字节码解析

// 代理类class文件存入本地磁盘方便我们反编译查看源码
System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "./code");

设置如上系统参数,会在code目录打印cglib动态生成的代码

UserServiceImpl$$EnhancerByCGLIB$$30794112:cglib生成的代理类,继承被代理类UserServiceImpl,实现net.sf.cglib.proxy.Factory接口
UserServiceImpl$$EnhancerByCGLIB$$30794112$$FastClassByCGLIB$$5d581559:代理类UserServiceImpl$$EnhancerByCGLIB$$30794112的索引类,继承net.sf.cglib.reflect.FastClass,记录了代理类的所有方法的索引,通过索引调用代理类的对应方法。
UserServiceImpl$$FastClassByCGLIB$$667bfe0a:是被代理类proxy.UserServiceImpl的索引类。功能同上

代理类

代理类重写了被代理类的say,say2方法,还有Object的equals,toString,hashCode,clone方法,say方法内部调用proxy.cglib.MyInterceptor#intercept进行增强。

public class UserServiceImpl$$EnhancerByCGLIB$$30794112 extends UserServiceImpl 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;
    private static final Method CGLIB$say2$0$Method;
    private static final MethodProxy CGLIB$say2$0$Proxy;
    private static final Object[] CGLIB$emptyArgs;
    private static final Method CGLIB$say$1$Method;
    private static final MethodProxy CGLIB$say$1$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 var0 = Class.forName("proxy.UserServiceImpl$$EnhancerByCGLIB$$30794112");
        Class var1;
        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$2$Method = var10000[0];
        CGLIB$equals$2$Proxy = MethodProxy.create(var1, var0, "(Ljava/lang/Object;)Z", "equals", "CGLIB$equals$2");
        CGLIB$toString$3$Method = var10000[1];
        CGLIB$toString$3$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/String;", "toString", "CGLIB$toString$3");
        CGLIB$hashCode$4$Method = var10000[2];
        CGLIB$hashCode$4$Proxy = MethodProxy.create(var1, var0, "()I", "hashCode", "CGLIB$hashCode$4");
        CGLIB$clone$5$Method = var10000[3];
        CGLIB$clone$5$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/Object;", "clone", "CGLIB$clone$5");
        var10000 = ReflectUtils.findMethods(new String[]"say2", "()V", "say", "()V", (var1 = Class.forName("proxy.UserServiceImpl")).getDeclaredMethods());
        CGLIB$say2$0$Method = var10000[0];
        CGLIB$say2$0$Proxy = MethodProxy.create(var1, var0, "()V", "say2", "CGLIB$say2$0");
        CGLIB$say$1$Method = var10000[1];
        CGLIB$say$1$Proxy = MethodProxy.create(var1, var0, "()V", "say", "CGLIB$say$1");
    

    final void CGLIB$say2$0() 
        super.say2();
    

    public final void say2() 
        MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
        if (var10000 == null) 
            CGLIB$BIND_CALLBACKS(this);
            var10000 = this.CGLIB$CALLBACK_0;
        

        if (var10000 != null) 
            var10000.intercept(this, CGLIB$say2$0$Method, CGLIB$emptyArgs, CGLIB$say2$0$Proxy);
         else 
            super.say2();
        
    

    final void CGLIB$say$1() 
        super.say();
    

    public final void say() 
        MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
        if (var10000 == null) 
            CGLIB$BIND_CALLBACKS(this);
            var10000 = this.CGLIB$CALLBACK_0;
        

        if (var10000 != null) 
            var10000.intercept(this, CGLIB$say$1$Method, CGLIB$emptyArgs, CGLIB$say$1$Proxy);
         else 
            super.say();
        
    

    final boolean CGLIB$equals$2(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$2$Method, new Object[]var1, CGLIB$equals$2$Proxy);
            return var2 == null ? false : (Boolean)var2;
         else 
            return super.equals(var1);
        
    

    final String CGLIB$toString$3() 
        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$3$Method, CGLIB$emptyArgs, CGLIB$toString$3$Proxy) : super.toString();
    

    final int CGLIB$hashCode$4() 
        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$4$Method, CGLIB$emptyArgs, CGLIB$hashCode$4$Proxy);
            return var1 == null ? 0 : ((Number)var1).intValue();
         else 
            return super.hashCode();
        
    

    final Object CGLIB$clone$5() 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$5$Method, CGLIB$emptyArgs, CGLIB$clone$5$Proxy) : super.clone();
    

    public static MethodProxy CGLIB$findMethodProxy(Signature var0) 
        String var10000 = var0.toString();
        switch(var10000.hashCode()) 
        case -909388886:
            if (var10000.equals("say()V")) 
                return CGLIB$say$1$Proxy;
            
            break;
        case -508378822:
            if (var10000.equals("clone()Ljava/lang/Object;")) 
                return CGLIB$clone$5$Proxy;
            
            break;
        case 1826985398:
            if (var10000.equals("equals(Ljava/lang/Object;)Z")) 
                return CGLIB$equals$2$Proxy;
            
            break;
        case 1874011246:
            if (var10000.equals("say2()V")) 
                return CGLIB$say2$0$Proxy;
            
            break;
        case 1913648695:
            if (var10000.equals("toString()Ljava/lang/String;")) 
                return CGLIB$toString$3$Proxy;
            
            break;
        case 1984935277:
            if (var10000.equals("hashCode()I")) 
                return CGLIB$hashCode$4$Proxy;
            
        

        return null;
    

    public UserServiceImpl$$EnhancerByCGLIB$$30794112() 
        CGLIB$BIND_CALLBACKS(this);
    

    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;
    

    private static final void CGLIB$BIND_CALLBACKS(Object var0) 
        UserServiceImpl$$EnhancerByCGLIB$$30794112 var1 = (UserServiceImpl$$EnhancerByCGLIB$$30794112)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];
        

    

    public Object newInstance(Callback[] var1) 
        CGLIB$SET_THREAD_CALLBACKS(var1);
        UserServiceImpl$$EnhancerByCGLIB$$30794112 var10000 = new UserServiceImpl$$EnhancerByCGLIB$$30794112();
        CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
        return var10000;
    

    public Object newInstance(Callback var1) 
        CGLIB$SET_THREAD_CALLBACKS(new Callback[]var1);
        UserServiceImpl$$EnhancerByCGLIB$$30794112 var10000 = new UserServiceImpl$$EnhancerByCGLIB$$30794112();
        CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
        return var10000;
    

    public Object newInstance(Class[] var1, Object[] var2, Callback[] var3) 
        CGLIB$SET_THREAD_CALLBACKS(var3);
        UserServiceImpl$$EnhancerByCGLIB$$30794112 var10000 = new UserServiceImpl$$EnhancerByCGLIB$$30794112;
        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();
    

代理类索引类(继承FastClass)

记录了代理类UserServiceImpl$EnhancerByCGLIB$30794112的所有方法的索引,通过proxy.UserServiceImpl$EnhancerByCGLIB$30794112$FastClassByCGLIB$5d581559#getIndex(net.sf.cglib.core.Signature)获取索引,通过proxy.UserServiceImpl$EnhancerByCGLIB$30794112$FastClassByCGLIB$5d581559#invoke方法,根据索引调用对应的代理类的方法。

public class UserServiceImpl$$EnhancerByCGLIB$$30794112$$FastClassByCGLIB$$5d581559 extends FastClass 
    public UserServiceImpl$$EnhancerByCGLIB$$30794112$$FastClassByCGLIB$$5d581559(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 5;
            
            break;
        case -1457535688:
            if (var10000.equals("CGLIB$STATICHOOK1()V")) 
                return 8;
            
            break;
        case -1411812934:
            if (var10000.equals("CGLIB$hashCode$4()I")) 
                return 13;
            
            break;
        case -909388886:
            if (var10000.equals("say()V")) 
                return 1;
            
            break;
        case -894172689:
            if (var10000.equals("newInstance(Lnet/sf/cglib/proxy/Callback;)Ljava/lang/Object;")) 
                return 22;
            
            break;
        case -623122092:
            if (var10000.equals("CGLIB$findMethodProxy(Lnet/sf/cglib/core/Signature;)Lnet/sf/cglib/proxy/MethodProxy;")) 
                return 15;
            
            break;
        case -560613858:
            if (var10000.equals("finalMethod()V")) 
                return 23;
            
            break;
        case -508378822:
            if (var10000.equals("clone()Ljava/lang/Object;")) 
                return 19;
            
            break;
        case -419626537:
            if (var10000.equals("setCallbacks([Lnet/sf/cglib/proxy/Callback;)V")) 
                return 3;
            
            break;
        case 374345669:
            if (var10000.equals("CGLIB$equals$2(Ljava/lang/Object;)Z")) 
                return 11;
            
            break;
        case 560567118:
            if (var10000.equals("setCallback(ILnet/sf/cglib/proxy/Callback;)V")) 
                return 2;
            
            break;
        case 811063227:
            if (var10000.equals("newInstance([Ljava/lang/Class;[Ljava/lang/Object;[Lnet/sf/cglib/proxy/Callback;)Ljava/lang/Object;")) 
                return 21;
            
            break;
        case 906868927:
            if (var10000.equals("CGLIB$say2$0()V")) 
                return 9;
            
            break;
        case 973717575:
            if (var10000.equals("getCallbacks()[Lnet/sf/cglib/proxy/Callback;")) 
                return 7;
            
            break;
        case 1221173700:
            if (var10000.equals("newInstance([Lnet/sf/cglib/proxy/Callback;)Ljava/lang/Object;")) 
                return 20;
            
            break;
        case 1230699260:
            if (var10000.equals("getCallback(I)Lnet/sf/cglib/proxy/Callback;")) 
                return 6;
            
            break;
        case 1517819849:
            if (var10000.equals("CGLIB$toString$3()Ljava/lang/String;")) 
                return 12;
            
            break;
        case 1540724864:
            if (var10000.equals("CGLIB$say$1()V")) 
                return 10;
            
            break;
        case 1584330438:
            if (var10000.equals("CGLIB$SET_STATIC_CALLBACKS([Lnet/sf/cglib/proxy/Callback;)V")) 
                return 4;
            
            break;
        case 1625931814:
            if (var10000.equals("staticMethod()V")) 
                return 24;
            
            break;
        case 1826985398:
            if (var10000.equals("equals(Ljava/lang/Object;)Z")) 
                return 16;
            
            break;
        case 1874011246:
            if (var10000.equals("say2()V")) 
                return 0;
            
            break;
        case 1913648695:
            if (var10000.equals("toString()Ljava/lang/String;")) 
                return 17;
            
            break;
        case 1984935277:
            if (var10000.equals("hashCode()I")) 
                return 18;
            
            break;
        case 2011844968:
            if (var10000.equals("CGLIB$clone$5()Ljava/lang/Object;")) 
                return 14;
            
        

        return -1;
    

    public int getIndex(String var1, Class[] var2) 
        switch(var1.hashCode()) 
        case -1776922004:
            if (var1.equals("toString")) 
                switch(var2.length) 
                case 0:
                    return 17;
                
            
            break;
        case -1295482945:
            if (var1.equals("equals")) 
                switch(var2.length) 
                case 1:
                    if (var2[0].getName().equals("java.lang.Object")) 
                        return 16;
                    
                
            
            break;
        case -1053468136:
            if (var1.equals("getCallbacks")) 
                switch(var2.length) 
                case 0:
                    return 7;
                
            
            break;
        case -124978608:
            if (var1.equals("CGLIB$equals$2")) 
                switch(var2.length) 
                case 1:
                    if (var2[0].getName().equals("java.lang.Object")) 
                        return 11;
                    
                
            
            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 4;
                    
                
            
            break;
        case -29025554:
            if (var1.equals("CGLIB$hashCode$4")) 
                switch(var2.length) 
                case 0:
                    return 13;
                
            
            break;
        case 113643:
            if (var1.equals("say")) 
                switch(var2.length) 
                case 0:
                    return 1;
                
            
            break;
        case 3522983:
            if (var1.equals("say2")) 
                switch(var2.length) 
                case 0:
                    return 0;
                
            
            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 5;
                    
                
            
            break;
        case 94756189:
            if (var1.equals("clone")) 
                switch(var2.length) 
                case 0:
                    return 19;
                
            
            break;
        case 147696667:
            if (var1.equals("hashCode")) 
                switch(var2.length) 
                case 0:
                    return 18;
                
            
            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 3;
                    
                
            
            break;
        case 511112950:
            if (var1.equals("CGLIB$say2$0")) 
                switch(var2.length) 
                case 0:
                    return 9;
                
            
            break;
        case 1124865749:
            if (var1.equals("CGLIB$say$1")) 
                switch(var2.length) 
                case 0:
                    return 10;
                
            
            break;
        case 1154623345:
            if (var1.equals("CGLIB$findMethodProxy")) 
                switch(var2.length) 
                case 1:
                    if (var2[0].getName().equals("net.sf.cglib.core.Signature")) 
                        return 15;
                    
                
            
            break;
        case 1154711791:
            if (var1.equals("staticMethod")) 
                switch(var2.length) 
                case 0:
                    return 24;
                
            
            break;
        case 1543336190:
            if (var1.equals("CGLIB$toString$3")) 
                switch(var2.length) 
                case 0:
                    return 12;
                
            
            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 22;
                        
                        break;
                    case 1730110032:
                        if (var10001.equals("[Lnet.sf.cglib.proxy.Callback;")) 
                            return 20;
                        
                    
                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 21;
                    
                
            
            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 2;
                    
                
            
            break;
        case 1900285431:
            if (var1.equals("finalMethod")) 
                switch(var2.length) 
                case 0:
                    return 23;
                
            
            break;
        case 1905679803:
            if (var1.equals("getCallback")) 
                switch(var2.length) 
                case 1:
                    if (var2[0].getName().equals("int")) 
                        return 6;
                    
                
            
            break;
        case 1951977611:
            if (var1.equals("CGLIB$clone$5")) 
                switch(var2.length) 
                case 0:
                    return 14;
                
            
        

        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 
        30794112 var10000 = (30794112)var2;
        int var10001 = var1;

        try 
            switch(var10001) 
            case 0:
                var10000.say2();
                return null;
            case 1:
                var10000.say();
                return null;
            case 2:
                var10000.setCallback(((Number)var3[0]).intValue(), (Callback)var3[1]);
                return null;
            case 3:
                var10000.setCallbacks((Callback[])var3[0]);
                return null;
            case 4:
                30794112.CGLIB$SET_STATIC_CALLBACKS((Callback[])var3[0]);
                return null;
            case 5:
                30794112.CGLIB$SET_THREAD_CALLBACKS((Callback[])var3[0]);
                return null;
            case 6:
                return var10000.getCallback(((Number)var3[0]).intValue());
            case 7:
                return var10000.getCallbacks();
            case 8:
                30794112.CGLIB$STATICHOOK1();
                return null;
            case 9:
                var10000.CGLIB$say2$0();
                return null;
            case 10:
                var10000.CGLIB$say$1();
                return null;
            case 11:
                return new Boolean(var10000.CGLIB$equals$2(var3[0]));
            case 12:
                return var10000.CGLIB$toString$3();
            case 13:
                return new Integer(var10000.CGLIB$hashCode$4());
            case 14:
                return var10000.CGLIB$clone$5();
            case 15:
                return 30794112.CGLIB$findMethodProxy((Signature)var3[0]);
            case 16:
                return new Boolean(var10000.equals(var3[0]));
            case 17:
                return var10000.toString();
            case 18:
                return new Integer(var10000.hashCode());
            case 19:
                return var10000.clone();
            case 20:
                return var10000.newInstance((Callback[])var3[0]);
            case 21:
                return var10000.newInstance((Class[])var3[0], (Object[])var3[1], (Callback[])var3[2]);
            case 22:
                return var10000.newInstance((Callback)var3[0]);
            case 23:
                var10000.finalMethod();
                return null;
            case 24:
                UserServiceImpl.staticMethod();
                return null;
            
         catch (Throwable var4) 
            throw new InvocationTargetException(var4);
        

        throw new IllegalArgumentException("Cannot find matching method/constructor");
    

    public Object newInstance(int var1, Object[] var2) throws InvocationTargetException 
        30794112 var10000 = new 30794112;
        30794112 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 24;
    

被代理类索引类(继承FastClass)

原理同上

public class UserServiceImpl$$FastClassByCGLIB$$667bfe0a extends FastClass 
    public UserServiceImpl$$FastClassByCGLIB$$667bfe0a(Class var1) 
        super(var1);
    

    public int getIndex(Signature var1) 
        String var10000 = var1.toString();
        switch(var10000.hashCode()) 
        case -909388886:
            if (var10000.equals("say()V")) 
                return 1;
            
            break;
        case -560613858:
            if (var10000.equals("finalMethod()V")) 
                return 2;
            
            break;
        case 1625931814:
            if (var10000.equals("staticMethod()V")) 
                return 3;
            
            break;
        case 1826985398:
            if (var10000.equals("equals(Ljava/lang/Object;)Z")) 
                return 4;
            
            break;
        case 1874011246:
            if (var10000.equals("say2()V")) 
                return 0;
            
            break;
        case 1913648695:
            if (var10000.equals("toString()Ljava/lang/String;")) 
                return 5;
            
            break;
        case 1984935277:
            if (var10000.equals("hashCode()I")) 
                return 6;
            
        

        return -1;
    

    public int getIndex(String var1, Class[] var2) 
        switch(var1.hashCode()) 
        case -1776922004:
            if (var1.equals("toString")) 
                switch(var2.length) 
                case 0:
                    return 5;
                
            
            break;
        case -1295482945:
            if (var1.equals("equals")) 
                switch(var2.length) 
                case 1:
                    if (var2[0].getName().equals("java.lang.Object")) 
                        return 4;
                    
                
            
            break;
        case 113643:
            if (var1.equals("say")) 
                switch(var2.length) 
                case 0:
                    return 1;
                
            
            break;
        case 3522983:
            if (var1.equals("say2")) 
                switch(var2.length) 
                case 0:
                    return 0;
                
            
            break;
        case 147696667:
            if (var1.equals("hashCode")) 
                switch(var2.length) 
                case 0:
                    return 6;
                
            
            break;
        case 1154711791:
            if (var1.equals("staticMethod")) 
                switch(var2.length) 
                case 0:
                    return 3;
                
            
            break;
        case 1900285431:
            if (var1.equals("finalMethod")) 
                switch(var2.length) 
                case 0:
                    return 2;
                
            
        

        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 
        UserServiceImpl var10000 = (UserServiceImpl)var2;
        int var10001 = var1;

        try 
            switch(var10001) 
            case 0:
                var10000.say2();
                return null;
            case 1:
                var10000.say();
                return null;
            case 2:
                var10000.finalMethod();
                return null;
            case 3:
                UserServiceImpl.staticMethod();
                return null;
            case 4:
                return new Boolean(var10000.equals(var3[0]));
            case 5:
                return var10000.toString();
            case 6:
                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 
        UserServiceImpl var10000 = new UserServiceImpl;
        UserServiceImpl 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 6;
    

代码跟踪

通过调用栈显示,

proxy.UserServiceImpl$EnhancerByCGLIB$30794112#say 内部调用了proxy.cglib.MyInterceptor#intercept ,intercept内部调用了net.sf.cglib.proxy.MethodProxy#invokeSuper,invokeSuper内部调用了proxy.UserServiceImpl$EnhancerByCGLIB$30794112$FastClassByCGLIB$5d581559#invoke,参数索引值是10。如下图二,索引10是代理类proxy.UserServiceImpl$EnhancerByCGLIB$30794112#CGLIB$say$0方法,CGLIB$say$0方法内部调用了super.say()父类(被代理类)方法。

Java动态代理和cglib比较

生成代理类技术不同

  • java动态代理:jdk自带类ProxyGenerator生成class字节码
  • cglib:通过ASM框架生成class字节码文件

生成代理类的方式不同

  • java动态代理:代理类继承java.lang.reflect.Proxy,实现被代理类的接口
  • cglib:代理类继承被代理类,实现net.sf.cglib.proxy.Factory

生成类数量不同

  • java动态代理:生成一个proxy类
  • cglib:生成一个proxy,两个fastclass类

调用方式不同

  • java动态代理:代理类->InvocationHandler->反射调用被代理类方法
  • cglib:代理类->MethodInterceptor->调用索引类invoke->直接调用被代理类方法

性能比较

网上找到比较多的说明如下:

jdk6之前比使用 Java反射效率要高,在 jdk6jdk7jdk8 逐步对 JDK 动态代理优化之后,在调用次数较少的情况下,JDK 代理效率 高于 CGLIB 代理效率。只有当进行大量调用的时候,jdk6jdk7CGLIB 代理效率低一点,但是到 jdk8 的时候,jdk 代理效率高于 CGLIB 代理,总之,每一次 jdk 版本升级JDK 代理效率 都得到提升,而 CGLIB 代理效率 确有点跟不上步伐。

jdk动态代理和cglib动态代理的区别

CGLIB代理:

CGLIB底层:使用字节码处理框架ASM,来转换字节码并生成新的类。 

CGLIB(CODE GENERLIZE LIBRARY)代理是针对类实现代理,主要是对指定的类生成一个子类,覆盖其中的所有方法,所以该类或方法不能声明称final的。

如果目标对象实现了接口,可以强制使用CGLIB实现代理。

如果目标对象没有实现接口,则默认会采用CGLIB代理; 

为什么jdk动态代理必须基于接口 
原因如下: 
1、生成的代理类继承了Proxy,由于java是单继承,所以只能实现接口,通过接口实现 

2、从代理模式的设计来说,充分利用了java的多态特性,也符合基于接口编码的规范 

为什么需要接口,先上结论

1.在需要继承proxy类获得有关方法和InvocationHandler构造方法传参的同时,java不能同时继承两个类,我们需要和想要代理的类建立联系,只能实现一个接口

2.需要反射获得代理类的有关参数,必须要通过某个类,反射获取有关方法,如本次测试用的 :printSomeThing

3.成功返回的是object类型,要获取原类,只能继承/实现,或者就是那个代理类

4.对具体实现的方法内部并不关心,这个交给InvocationHandler.invoke那个方法里去处理就好了,我只想根据你给我的接口反射出对我有用的东西。

5.考虑到设计模式,以及proxy编者编写代码的逻辑使然

 

jdk代理和cglib代理的区别:(https://blog.csdn.net/yhl_jxy/article/details/80635012

 

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