interface AddInterface{
 int add(int a, int b);
}

interface SubInterface{
 int sub(int a, int b);
}

class Arithmetic implements AddInterface, SubInterface{
 @Override
 public int sub(int a, int b) {
  return a-b;
 }

 @Override
 public int add(int a, int b) {
  return a+b;
 }
}

class JdkDPQueryHandler implements InvocationHandler{
 private Arithmetic real;
 public JdkDPQueryHandler(Arithmetic real){
  this.real = real;
 }
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
  String methodName = method.getName();
  System.out.println(method);
  System.out.println("the method: " + methodName + "开始, 参数: "+Arrays.asList(args));
  Object result = method.invoke(real, args);
  System.out.println("the method: "+methodName+"结束, 结果: " + result);
  return result;
 }
}

public class Main{
 private static int a = 4, b = 2;
 
 public static Object createJDKProxy(Arithmetic real){
  Object proxyArithmetic = Proxy.newProxyInstance(real.getClass().getClassLoader(),
    real.getClass().getInterfaces(), new JdkDPQueryHandler(real)); 
  return proxyArithmetic;
 }
 
 public static void main(String[] args){
  Arithmetic real = new Arithmetic();
  Object proxyArithmetic = createJDKProxy(real);
  ((AddInterface)proxyArithmetic).add(a, b);
  ((SubInterface)proxyArithmetic).sub(a, b);
 }
}

public interface MethodInterceptor extends Callback { 
 public Object intercept(Object obj, java.lang.reflect.Method method, Object[] args,MethodProxy proxy) throws Throwable; 
} 
public interface InvocationHandler { 
  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable; 
} 

class CglibDPQueryInterceptor implements MethodInterceptor{
 private Arithmetic real;
 public CglibDPQueryInterceptor(Arithmetic real){
  this.real = real;
 }
 
 @Override
 public Object intercept(Object target, Method method, Object[] args, MethodProxy proxy) throws Throwable {
  String methodName = method.getName();
  System.out.println(method);
  System.out.println("the method: " + methodName + "开始, 参数: "+Arrays.asList(args));
  //Object result = method.invoke(real, args);//两种方式都是可以得
  Object result = proxy.invoke(real, args);
  System.out.println("the method: "+methodName+"结束, 结果: " + result);
  return result;
 }
}

public class Main{
 private static int a = 4, b = 2;
 public static Object createCglibProxy(Arithmetic real){
   Enhancer enhancer = new Enhancer();
   enhancer.setCallback(new CglibDPQueryInterceptor(real));
   enhancer.setInterfaces(real.getClass().getInterfaces());
   return enhancer.create();
 }
 
 public static void main(String[] args){
  Arithmetic real = new Arithmetic();  
  Object proxyArithmetic = createCglibProxy(real);  
  ((AddInterface)proxyArithmetic).add(a, b);
  ((SubInterface)proxyArithmetic).sub(a, b);
 }
}

public Object invoke (Object obj, Object[] args) throws Throwable 
public Object invokeSuper(Object obj, Object[] args) throws Throwable

interface SolveInterface{
 void solve();
}

class Real implements SolveInterface{
 public void solve(){
  System.out.println("Real Solve!");
 }
}

class Target extends Real{
 private Object obj;
 
 public void setObject(Object obj){
  this.obj = obj;
 }
 
 private void invoke(){
  try {
   Method method = SolveInterface.class.getMethod("solve", new Class[]{});
   method.invoke(obj, new Class[]{});
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
 public void solve(){
  System.out.println("Target Solve!");
  invoke();
 }
}

public class Main{public static void main(String[] args) throws Exception{   
    Target target = new Target();
    target.setObject(new Real());//正确
    //target.setObject(target);//发生循环调用
    target.solve();
  }
}

class CglibDPQueryInterceptor implements MethodInterceptor{
  
  @Override
  public Object intercept(Object target, Method method, Object[] args, MethodProxy proxy) throws Throwable {
    String methodName = method.getName();
    System.out.println(method);
    System.out.println("the method: " + methodName + "开始, 参数: "+Arrays.asList(args));
    // 打印类信息 ：target.getClass()；省略
    Object result = proxy.invokeSuper(target, args);
    System.out.println("the method: "+methodName+"结束, 结果: " + result);
    return result;
  }
}

public class Main{
  private static int a = 4, b = 2;
public static Object createCglibProxy(){
     Enhancer enhancer = new Enhancer();
     enhancer.setCallback(new CglibDPQueryInterceptor());
     enhancer.setSuperclass(Arithmetic.class);
     return enhancer.create();
  }
  
  public static void main(String[] args){
    Arithmetic real = new Arithmetic();

    Object proxyArithmetic = createCglibProxy();
    
    ((AddInterface)proxyArithmetic).add(a, b);
    ((SubInterface)proxyArithmetic).sub(a, b);
  }
}

public class com.test.Arithmetic$$EnhancerByCGLIB$$4fa786eb extends java.lang.Object

public class com.test.Arithmetic$$EnhancerByCGLIB$$4fa786eb extends com.test.Arithmetic

class JavassistDPQueryHandler implements MethodHandler{

  @Override
  public Object invoke(Object target, Method method, Method proxy, Object[] args) throws Throwable {
    String methodName = method.getName();
    System.out.println(method);
    System.out.println("the method: " + methodName + "开始, 参数: "+Arrays.asList(args));
    Object result = proxy.invoke(target, args);
    System.out.println("the method: "+methodName+"结束, 结果: " + result);
    return result;
  }
}

public class Main{
  private static int a = 4, b = 2;
public static Object createJavassistProxy() throws Exception{
    ProxyFactory factory = new ProxyFactory();
    factory.setSuperclass(Arithmetic.class);
    factory.setHandler(new JavassistDPQueryHandler());
    return factory.createClass().newInstance();
  }
  
  public static void main(String[] args) throws Exception{
    Arithmetic real = new Arithmetic();
    
    Object proxyArithmetic = createJavassistProxy();
    
    ((AddInterface)proxyArithmetic).add(a, b);
    ((SubInterface)proxyArithmetic).sub(a, b);
  }
}

public Object invoke(Object target, Method method, Method proxy, Object[] args)

//自定义拦截器接口
interface InterceptorHandler { 
  
  /** 
   * 调用动态代理对象的方法将反射本方法，可在本方法实现中添加类似AOP的事前事后操作，只有在本方法体中加入如下代码 
   * 被代理的方法才会被执行，返回值将返回给代理最后返回给程序 
   * @param obj Object 被代理的对象 
   * @param method Method 被代理对象的方法 
   * @param args Object[] 被代理对象的方法的参数 
   * @return Object 被代理对象的方法执行后的返回值 
   * @throws Throwable 
   */ 
  public Object invoke(Object obj, Method method, Object[] args) throws Throwable; 
} 

//拦截器的实现
class InterceptorHandlerImpl implements InterceptorHandler{
  @Override
  public Object invoke(Object obj, Method method, Object[] args) throws Throwable {
    String methodName = method.getName();
    System.out.println(method);
    System.out.println("the method: " + methodName + "开始, 参数: "+Arrays.asList(args));
    Object result = method.invoke(obj, args);
    System.out.println("the method: "+methodName+"结束, 结果: " + result);
    return result;
  }
}


class MyProxyImpl { 
  /** 动态代理类的类名后缀 */ 
  private final static String PROXY_CLASS_NAME_SUFFIX = "$MyProxy_"; 
  /** 拦截器接口 */ 
  private final static String INTERCEPTOR_HANDLER_INTERFACE = "com.test.InterceptorHandler"; 
  /** 动态代理类的类名索引，防止类名重复 */ 
  private static int proxyClassIndex = 1; 
   
  /** 
   * 暴露给用户的动态代理接口，返回某个接口的动态代理对象，注意本代理实现需和com.cuishen.myAop.InterceptorHandler拦截器配合 
   * 使用，即用户要使用本动态代理，需先实现com.cuishen.myAop.InterceptorHandler拦截器接口 
   * @param interfaceClassName String 要动态代理的接口类名, e.g test.StudentInfoService 
   * @param classToProxy String 要动态代理的接口的实现类的类名, e.g test.StudentInfoServiceImpl 
   * @param interceptorHandlerImplClassName String 用户提供的拦截器接口的实现类的类名 
   * @return Object 返回某个接口的动态代理对象 
   * @throws InstantiationException 
   * @throws IllegalAccessException 
   * @throws NotFoundException 
   * @throws CannotCompileException 
   * @throws ClassNotFoundException 
   * @see com.cuishen.myAop.InterceptorHandler 
   */ 
  public static Object newProxyInstance(String interfaceClassName, String classToProxy, String interceptorHandlerImplClassName) throws InstantiationException, IllegalAccessException, NotFoundException, CannotCompileException, ClassNotFoundException { 
    Class interfaceClass = Class.forName(interfaceClassName); 
    Class interceptorHandlerImplClass = Class.forName(interceptorHandlerImplClassName); 
    return dynamicImplementsInterface(classToProxy, interfaceClass, interceptorHandlerImplClass); 
  } 
   
  /** 
   * 动态实现要代理的接口 
   * @param classToProxy String 要动态代理的接口的实现类的类名, e.g test.StudentInfoServiceImpl 
   * @param interfaceClass Class 要动态代理的接口类, e.g test.StudentInfoService 
   * @param interceptorHandlerImplClass Class 用户提供的拦截器接口的实现类 
   * @return Object 返回某个接口的动态代理对象 
   * @throws NotFoundException 
   * @throws CannotCompileException 
   * @throws InstantiationException 
   * @throws IllegalAccessException 
   */ 
  private static Object dynamicImplementsInterface(String classToProxy, Class interfaceClass, Class interceptorHandlerImplClass) throws NotFoundException, CannotCompileException, InstantiationException, IllegalAccessException { 
    ClassPool cp = ClassPool.getDefault(); 
    String interfaceName = interfaceClass.getName(); 
    //动态指定代理类的类名 
    String proxyClassName = interfaceName + PROXY_CLASS_NAME_SUFFIX + proxyClassIndex++; 
    //要实现的接口的包名+接口名 
    String interfaceNamePath = interfaceName; 
     
    CtClass ctInterface = cp.getCtClass(interfaceNamePath); 
    CtClass cc = cp.makeClass(proxyClassName); 
    cc.addInterface(ctInterface); 
    Method [] methods = interfaceClass.getMethods(); 
    for(int i = 0; i < methods.length; i++) { 
      Method method = methods[i]; 
      dynamicImplementsMethodsFromInterface(classToProxy, cc, method, interceptorHandlerImplClass, i); 
    } 
    return (Object)cc.toClass().newInstance(); 
  } 
   
  /** 
   * 动态实现接口里的方法 
   * @param classToProxy String 要动态代理的接口的实现类的类名, e.g test.StudentInfoServiceImpl 
   * @param implementer CtClass 动态代理类的包装 
   * @param methodToImpl Method 动态代理类里面要实现的接口方法的包装 
   * @param interceptorClass Class 用户提供的拦截器实现类 
   * @param methodIndex int 要实现的方法的索引 
   * @throws CannotCompileException 
   */ 
  private static void dynamicImplementsMethodsFromInterface(String classToProxy, CtClass implementer, Method methodToImpl, Class interceptorClass, int methodIndex) throws CannotCompileException { 
    String methodCode = generateMethodCode(classToProxy, methodToImpl, interceptorClass, methodIndex); 
    CtMethod cm = CtNewMethod.make(methodCode, implementer); 
    implementer.addMethod(cm); 
  } 
   
  /** 
   * 动态组装方法体，当然代理里面的方法实现并不是简单的方法拷贝，而是反射调用了拦截器里的invoke方法，并将接收到的参数进行传递 
   * @param classToProxy String 要动态代理的接口的实现类的类名, e.g test.StudentInfoServiceImpl 
   * @param methodToImpl Method 动态代理类里面要实现的接口方法的包装 
   * @param interceptorClass Class 用户提供的拦截器实现类 
   * @param methodIndex int 要实现的方法的索引 
   * @return String 动态组装的方法的字符串 
   */ 
  private static String generateMethodCode(String classToProxy, Method methodToImpl, Class interceptorClass, int methodIndex) { 
    String methodName = methodToImpl.getName(); 
    String methodReturnType = methodToImpl.getReturnType().getName(); 
    Class[] parameters = methodToImpl.getParameterTypes(); 
    Class[] exceptionTypes = methodToImpl.getExceptionTypes(); 
    StringBuffer exceptionBuffer = new StringBuffer(); 
    //组装方法的Exception声明 
    if(exceptionTypes.length > 0) exceptionBuffer.append(" throws "); 
    for(int i = 0; i < exceptionTypes.length; i++) { 
      if(i != exceptionTypes.length - 1) exceptionBuffer.append(exceptionTypes[i].getName()).append(","); 
      else exceptionBuffer.append(exceptionTypes[i].getName()); 
    } 
    StringBuffer parameterBuffer = new StringBuffer(); 
    //组装方法的参数列表 
    for(int i = 0; i < parameters.length; i++) { 
      Class parameter = parameters[i]; 
      String parameterType = parameter.getName(); 
      //动态指定方法参数的变量名 
      String refName = "a" + i; 
      if(i != parameters.length - 1) parameterBuffer.append(parameterType).append(" " + refName).append(","); 
      else parameterBuffer.append(parameterType).append(" " + refName); 
    } 
    StringBuffer methodDeclare = new StringBuffer(); 
    //方法声明，由于是实现接口的方法，所以是public 
    methodDeclare.append("public ").append(methodReturnType).append(" ").append(methodName).append("(").append(parameterBuffer).append(")").append(exceptionBuffer).append(" {\n"); 
    String interceptorImplName = interceptorClass.getName(); 
    //方法体 
    methodDeclare.append(INTERCEPTOR_HANDLER_INTERFACE).append(" interceptor = new ").append(interceptorImplName).append("();\n"); 
    //反射调用用户的拦截器接口 
    methodDeclare.append("Object returnObj = interceptor.invoke(Class.forName(\"" + classToProxy + "\").newInstance(), Class.forName(\"" + classToProxy + "\").getMethods()[" + methodIndex + "], "); 
    //传递方法里的参数 
    if(parameters.length > 0) methodDeclare.append("new Object[]{");  
    for(int i = 0; i < parameters.length; i++) { 
      //($w) converts from a primitive type to the corresponding wrapper type: e.g. 
      //Integer i = ($w)5; 
      if(i != parameters.length - 1) methodDeclare.append("($w)a" + i + ","); 
      else methodDeclare.append("($w)a" + i); 
    } 
    if(parameters.length > 0) methodDeclare.append("});\n"); 
    else methodDeclare.append("null);\n"); 
    //对调用拦截器的返回值进行包装 
    if(methodToImpl.getReturnType().isPrimitive()) { 
      if(methodToImpl.getReturnType().equals(Boolean.TYPE)) methodDeclare.append("return ((Boolean)returnObj).booleanValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Integer.TYPE)) methodDeclare.append("return ((Integer)returnObj).intValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Long.TYPE)) methodDeclare.append("return ((Long)returnObj).longValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Float.TYPE)) methodDeclare.append("return ((Float)returnObj).floatValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Double.TYPE)) methodDeclare.append("return ((Double)returnObj).doubleValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Character.TYPE)) methodDeclare.append("return ((Character)returnObj).charValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Byte.TYPE)) methodDeclare.append("return ((Byte)returnObj).byteValue();\n"); 
      else if(methodToImpl.getReturnType().equals(Short.TYPE)) methodDeclare.append("return ((Short)returnObj).shortValue();\n"); 
    } else { 
      methodDeclare.append("return (" + methodReturnType + ")returnObj;\n"); 
    } 
    methodDeclare.append("}"); 
    System.out.println(methodDeclare.toString()); 
    return methodDeclare.toString(); 
  } 
   
} 

public class Main{   
  public static void main(String[] args) throws Exception{  
　　　　 //分别对应 代理类要实现的接口类名， 需要代理类的类名， 用户自定义拦截器实现类的类名
    Object proxyArithmetic = MyProxyImpl.newProxyInstance("com.test.ArithmeticInterface", "com.test.Arithmetic", 
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　"com.test.InterceptorHandlerImpl");
    ((ArithmeticInterface)proxyArithmetic).add(a, b);
    ((ArithmeticInterface)proxyArithmetic).sub(a, b);    
  }
}

public int add(int a0,int a1) {
com.test.InterceptorHandler interceptor = new com.test.InterceptorHandlerImpl();
Object returnObj = interceptor.invoke(Class.forName("com.test.Arithmetic").newInstance(), Class.forName("com.test.Arithmetic").getMethods()[0], new Object[]{($w)a0,($w)a1});
return ((Integer)returnObj).intValue();
}
public int sub(int a0,int a1) {
com.test.InterceptorHandler interceptor = new com.test.InterceptorHandlerImpl();
Object returnObj = interceptor.invoke(Class.forName("com.test.Arithmetic").newInstance(), Class.forName("com.test.Arithmetic").getMethods()[1], new Object[]{($w)a0,($w)a1});
return ((Integer)returnObj).intValue();
}