JDK与CGLib动态代理区别

今天稍微看了下JDK与CGLib动态代理，对两者的区别有所了解。
但是同样是生成字节码，在哪里会有所不同，粗略的思考了一下，记录如下(暂时记录，以后有时间再细细研究)

JDK动态代理

生成的字节码示例如下：

//这里很清楚了,代理类继承了Proxy类,并且实现了Proxy.newProxyInstance这个方法中传入的接口    
public final class $Proxy0 extends Proxy implements ITest {
    private static Method m1;
    private static Method m2;
    private static Method m3;
    private static Method m0;

    public $Proxy0(InvocationHandler var1) throws  {
        super(var1);
    }

    public final boolean equals(Object var1) throws  {
        try {
            return ((Boolean)super.h.invoke(this, m1, new Object[]{var1})).booleanValue();
        } catch (RuntimeException | Error var3) {
            throw var3;
        } catch (Throwable var4) {
            throw new UndeclaredThrowableException(var4);
        }
    }

    public final String toString() throws  {
        try {
            return (String)super.h.invoke(this, m2, (Object[])null);
        } catch (RuntimeException | Error var2) {
            throw var2;
        } catch (Throwable var3) {
            throw new UndeclaredThrowableException(var3);
        }
    }

    public final void test(String var1) throws  {
        try {
            super.h.invoke(this, m3, new Object[]{var1});
        } catch (RuntimeException | Error var3) {
            throw var3;
        } catch (Throwable var4) {
            throw new UndeclaredThrowableException(var4);
        }
    }

    public final int hashCode() throws  {
        try {
            return ((Integer)super.h.invoke(this, m0, (Object[])null)).intValue();
        } catch (RuntimeException | Error var2) {
            throw var2;
        } catch (Throwable var3) {
            throw new UndeclaredThrowableException(var3);
        }
    }

    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("ITest").getMethod("test", new Class[]{Class.forName("java.lang.String")});
            m0 = Class.forName("java.lang.Object").getMethod("hashCode", new Class[0]);
        } catch (NoSuchMethodException var2) {
            throw new NoSuchMethodError(var2.getMessage());
        } catch (ClassNotFoundException var3) {
            throw new NoClassDefFoundError(var3.getMessage());
        }
    }
}

利用java反射调用目标类方法：super.h.invoke(this, m3, new Object[]{var1});

Cglib动态代理

生成的字节码文件会有多个文件：

1528041767270.png

public class Test$$EnhancerByCGLIB$$4e16a0e7 extends Test implements net.sf.cglib.proxy.Factory {
    private boolean CGLIB$BOUND;
    private static final java.lang.ThreadLocal CGLIB$THREAD_CALLBACKS;
    private static final net.sf.cglib.proxy.Callback[] CGLIB$STATIC_CALLBACKS;
    private net.sf.cglib.proxy.MethodInterceptor CGLIB$CALLBACK_0;
    private static final java.lang.reflect.Method CGLIB$test$0$Method;
    private static final net.sf.cglib.proxy.MethodProxy CGLIB$test$0$Proxy;
    private static final java.lang.Object[] CGLIB$emptyArgs;
    private static final java.lang.reflect.Method CGLIB$finalize$1$Method;
    private static final net.sf.cglib.proxy.MethodProxy CGLIB$finalize$1$Proxy;
    private static final java.lang.reflect.Method CGLIB$equals$2$Method;
    private static final net.sf.cglib.proxy.MethodProxy CGLIB$equals$2$Proxy;
    private static final java.lang.reflect.Method CGLIB$toString$3$Method;
    private static final net.sf.cglib.proxy.MethodProxy CGLIB$toString$3$Proxy;
    private static final java.lang.reflect.Method CGLIB$hashCode$4$Method;
    private static final net.sf.cglib.proxy.MethodProxy CGLIB$hashCode$4$Proxy;
    private static final java.lang.reflect.Method CGLIB$clone$5$Method;
    private static final net.sf.cglib.proxy.MethodProxy CGLIB$clone$5$Proxy;

    static void CGLIB$STATICHOOK1() { /* compiled code */ }

    final void CGLIB$test$0(java.lang.String s) { /* compiled code */ }

    public final void test(java.lang.String s) { /* compiled code */ }

    final void CGLIB$finalize$1() throws java.lang.Throwable { /* compiled code */ }

    protected final void finalize() throws java.lang.Throwable { /* compiled code */ }

    final boolean CGLIB$equals$2(java.lang.Object o) { /* compiled code */ }

    public final boolean equals(java.lang.Object o) { /* compiled code */ }
    ...

方法中没有具体的代码，看来得借助其他工具查看class文件(待续)
参看 cglib原理分析
Jdk动态代理的拦截对象是通过反射的机制来调用被拦截方法的，反射的效率比较低，所以cglib采用了FastClass的机制来实现对被拦截方法的调用。FastClass机制就是对一个类的方法建立索引，通过索引来直接调用相应的方法，