java-cglib动态代理原理
cglib使用
1.引入依赖
<!-- 添加cglib依赖 -->
<dependency>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
<version>3.3.0</version>
</dependency>
2.创建被代理类
public interface TestTransactionDao { public void processStudent(); public void processStudent2(); }
public class TestTransactionDaoImpl implements TestTransactionDao { @Override public void processStudent() { } @Override public void processStudent2() { } }
增强实现
public class ProcessStudentHandle implements MethodInterceptor { @Override public Object intercept(Object o, Method method, Object[] args, MethodProxy methodProxy) throws Throwable { System.out.println("Before method: " + method.getName()); Object result = methodProxy.invokeSuper(o, args); System.out.println("After method: " + method.getName()); return result; } }
3.cglib生成代理
public static void main(String[] args) { //将cglib动态生成的class输出到项目根目录 System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "./cglib"); Enhancer enhancer = new Enhancer(); enhancer.setSuperclass(TestTransactionDaoImpl.class); enhancer.setCallback(new ProcessStudentHandle()); TestTransactionDao dao = (TestTransactionDao) enhancer.create(); dao.processStudent(); }
4.
5.使用在线反编译
6.动态生成的源码
/* Decompiler 2161ms, total 3467ms, lines 283 */ package com.example.sampleaop.dao; 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;
//通过继承实现 public class TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7 extends TestTransactionDaoImpl 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;
//自定义增强实现 private MethodInterceptor CGLIB$CALLBACK_0; private static Object CGLIB$CALLBACK_FILTER; private static final Method CGLIB$processStudent2$0$Method; private static final MethodProxy CGLIB$processStudent2$0$Proxy; private static final Object[] CGLIB$emptyArgs; private static final Method CGLIB$processStudent$1$Method; private static final MethodProxy CGLIB$processStudent$1$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("com.example.sampleaop.dao.TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7"); Class var1;
//objct的基础方法 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$5");
//被代理类的方法 var10000 = ReflectUtils.findMethods(new String[]{"processStudent2", "()V", "processStudent", "()V"}, (var1 = Class.forName("com.example.sampleaop.dao.TestTransactionDaoImpl")).getDeclaredMethods()); CGLIB$processStudent2$0$Method = var10000[0]; CGLIB$processStudent2$0$Proxy = MethodProxy.create(var1, var0, "()V", "processStudent2", "CGLIB$processStudent2$0"); CGLIB$processStudent$1$Method = var10000[1]; CGLIB$processStudent$1$Proxy = MethodProxy.create(var1, var0, "()V", "processStudent", "CGLIB$processStudent$1"); } final void CGLIB$processStudent2$0() { super.processStudent2(); } public final void processStudent2() { MethodInterceptor var10000 = this.CGLIB$CALLBACK_0; if (var10000 == null) { CGLIB$BIND_CALLBACKS(this); var10000 = this.CGLIB$CALLBACK_0; } if (var10000 != null) {
//调用我们的增强实现 传入 var10000.intercept(this, CGLIB$processStudent2$0$Method, CGLIB$emptyArgs, CGLIB$processStudent2$0$Proxy); } else { super.processStudent2(); } } final void CGLIB$processStudent$1() { super.processStudent(); } public final void processStudent() { MethodInterceptor var10000 = this.CGLIB$CALLBACK_0; if (var10000 == null) { CGLIB$BIND_CALLBACKS(this); var10000 = this.CGLIB$CALLBACK_0; } if (var10000 != null) { var10000.intercept(this, CGLIB$processStudent$1$Method, CGLIB$emptyArgs, CGLIB$processStudent$1$Proxy); } else { super.processStudent(); } } 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$findMethodProxy(Signature var0) { String var10000 = var0.toString(); switch(var10000.hashCode()) { case -1229936855: if (var10000.equals("processStudent()V")) { return CGLIB$processStudent$1$Proxy; } break; case -508378822: if (var10000.equals("clone()Ljava/lang/Object;")) { return CGLIB$clone$5$Proxy; } break; case 526958799: if (var10000.equals("processStudent2()V")) { return CGLIB$processStudent2$0$Proxy; } break; case 1826985398: if (var10000.equals("equals(Ljava/lang/Object;)Z")) { return CGLIB$equals$2$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 TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7() { 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) { TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7 var1 = (TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7)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); TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7 var10000 = new TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7(); CGLIB$SET_THREAD_CALLBACKS((Callback[])null); return var10000; } public Object newInstance(Callback var1) { CGLIB$SET_THREAD_CALLBACKS(new Callback[]{var1}); TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7 var10000 = new TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7(); CGLIB$SET_THREAD_CALLBACKS((Callback[])null); return var10000; } public Object newInstance(Class[] var1, Object[] var2, Callback[] var3) { CGLIB$SET_THREAD_CALLBACKS(var3); TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7 var10000 = new TestTransactionDaoImpl$$EnhancerByCGLIB$$b6b704c7; 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(); } }
