I. Introduction

In software development, the proxy pattern is a commonly used design pattern that allows an object to be provided with a proxy to control access to the object. The proxy mode is divided into two forms: static proxy and dynamic proxy. They have significant differences in configuration and application scenarios. This article will discuss in detail the configuration differences between static proxys and dynamic proxys and their respective application scenarios.

2. Static proxy

Static proxy overview

Static proxy refers to the bytecode file of the proxy class that already exists before the program is run. The relationship between the proxy class and the target class is determined when the code is compiled. Static proxy is usually implemented by creating a new class that implements the same interface as the target class and calling the methods of the target class in it.

Static proxy configuration

The configuration of static proxy is relatively simple. Developers need to manually write the proxy class and call the method of the target object in it. The proxy class usually implements the same interface as the target class so that it can be called by the client instead of the target class.

Application scenarios of static proxy

Static proxies are usually used for some simple and fixed proxy requirements, such as logging, permission verification, etc. Since the proxy class of a static proxy is determined at compile time, it is not suitable for scenarios where the proxy class needs to change frequently.

3. Dynamic proxy

Dynamic proxy overview

Dynamic proxy refers to the bytecode file of the proxy class that is dynamically generated when the program is running and loaded into the JVM. Unlike static proxies, the relationship between the proxy class and the target class of a dynamic proxy is determined at runtime.

Dynamic proxy configuration

The configuration of dynamic proxy is relatively complex and usually requires the use of Java's reflection mechanism and dynamic proxy API (such as Java's Proxy class). Developers need to define an implementation class of the InvocationHandler interface to handle method calls on the proxy object. When a method on the proxy object is called, the invoke method of the InvocationHandler will be called. Developers can implement calls to the target object and additional logic processing in this method.

Application scenarios of dynamic proxys

Dynamic proxy is suitable for scenarios where proxy classes need to change frequently, such as AOP (aspect-oriented programming) framework, RPC (remote procedure call) framework, etc. In these scenarios, the generation and configuration of proxy classes are usually automatically completed by the framework, and developers do not need to manually write proxy class code.

4. Comparison between static proxy and dynamic proxy

Configuration complexity

The configuration of static proxy is relatively simple, developers only need to write the proxy class. The configuration of dynamic proxy is relatively complex and requires the use of reflection mechanism and dynamic proxy API.

flexibility

Dynamic proxys have higher flexibility and can dynamically generate proxy classes at runtime to adapt to different proxy needs. The proxy class of a static proxy is determined at compile time and has poor flexibility.

performance

Because the proxy class of a static proxy is determined at compile time, its performance is usually better than that of a dynamic proxy. Dynamic proxys need to generate a bytecode file of the proxy class and load it into the JVM during runtime, which will add a certain amount of overhead.

5. Application scenario selection

When choosing between using a static proxy or a dynamic proxy, you need to weigh it based on specific business needs. For simple and fixed proxy requirements, such as logging, permission verification, etc., you can use static proxy.

For scenarios that require frequent changes to proxy classes, such as AOP frameworks, RPC frameworks, etc., dynamic proxies are more suitable.

6. Summary

Static proxy and dynamic proxy are two commonly used proxy mode implementations. They have significant differences in configuration and application scenarios. In actual development, the appropriate proxy method should be selected according to specific needs to achieve code flexibility and maintainability.

At the same time, with the continuous development of technology, more new proxy implementation methods and technologies may appear in the future. We need to continue to pay attention to and learn new knowledge and technologies to adapt to changing needs and challenges.