The Proxy pattern is a structural design pattern that allows indirect access to another object by creating a proxy object. The Proxy pattern can reduce the coupling of the system and increase the flexibility of the code. The following is a complete sample code for implementing the Proxy pattern in Python: ```python #In this example, we will restrict access to the original object through a proxy object #Define a raw object interface class Image: def display(self): pass #Define the original object class class RealImage(Image): def __init__(self, filename): self._filename = filename self.load_from_disk() def load_from_disk(self): print("Loading image: " + self._filename) def display(self): print("Displaying image: " + self._filename) #Defining Proxy Object Classes class ProxyImage(Image): def __init__(self, filename): self._filename = filename self._real_image = None def display(self): if self._real_image is None: self._real_image = RealImage(self._filename) self._real_image.display() #Using Proxy Objects image = ProxyImage("example.jpg") #The original object will be loaded on the first access image.display() #Directly use the original object for the second and subsequent access image.display() ``` In the above example, 'RealImage' is a primitive object class that implements the 'Image' interface, representing the true image object` ProxyImage 'is a proxy object class that also implements the' Image 'interface, which includes references to' RealImage 'and creates' RealImage' objects when needed to handle the actual image display. By using proxy objects, we can control and manage the original objects when needed, such as implementing delayed loading of images or restricting image access permissions. In the sample code above, we used lazy loading method, which only loads the original object the first time the 'display()' method is called. In the second and subsequent calls, directly using the already loaded original objects improves the performance and efficiency of the system. The output result is: ``` Loading image: example.jpg Displaying image: example.jpg Displaying image: example.jpg ```

In the Spring framework, AOP (Aspect Oriented Programming) is an important design pattern. It realizes modular development by separating Cross-cutting concern (such as logging, transaction management, etc.) from business logic modules. The core idea of AOP is to weave additional logic before and after the method execution of the target object through the Proxy pattern, so as to realize the function of Cross-cutting concern. In the Spring framework, the implementation of AOP mainly utilizes dynamic proxies. When we use Spring AOP, the framework helps us automatically create a proxy object to add additional logic before and after the method execution of the target object. Spring provides two implementations of AOP: interface based proxies and class based proxies. The interface based proxy is implemented using JDK's dynamic proxy. In this proxy method, the proxy object implements the interface of the target object, and when calling the proxy object's methods, it actually calls the InvocationHandler's invoke method through a reflection mechanism. In the invoke method, we can add additional logic to complete the function of Cross-cutting concern. The following is an example of the implementation code of the interface based Proxy pattern AOP in the Spring framework: ```java import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation; public class LoggingInterceptor implements MethodInterceptor { @Override public Object invoke(MethodInvocation invocation) throws Throwable { //Logic before executing the target method System.out.println("Before method: " + invocation.getMethod().getName()); //Calling the target method Object result = invocation.proceed(); //Logic after executing the target method System.out.println("After method: " + invocation.getMethod().getName()); return result; } } ``` Class based proxies use CGLIB to generate proxy classes. In this proxy mode, the proxy object inherits the class of the target object and rewrites the method of the target object. Additional logic can be added in the method to realize the function of Cross-cutting concern. The following is an example of the implementation code of the class based Proxy pattern AOP in the Spring framework: ```java import org.springframework.cglib.proxy.MethodInterceptor; import org.springframework.cglib.proxy.MethodProxy; public class LoggingInterceptor implements MethodInterceptor { @Override public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { //Logic before executing the target method System.out.println("Before method: " + method.getName()); //Calling the target method Object result = proxy.invokeSuper(obj, args); //Logic after executing the target method System.out.println("After method: " + method.getName()); return result; } } ``` Summary: AOP in the Spring framework is implemented through the Proxy pattern, weaving additional logic before and after the method execution of the target object, so as to realize the function of Cross-cutting concern. AOP can help us achieve Cross-cutting concern such as logging, transaction management, security verification, and improve the Reusability and maintainability of the code.