In -depth understanding of the working principle and advantage of the CGLIB FULL framework
In -depth understanding of the working principle and advantage of the CGLIB FULL framework
Introduction:
CGLIB is a powerful code generating library, which is a high -performance code generating library based on the ASM bytecode operation framework.In Java, interface -oriented dynamic agents are usually used to implement AOP (facing surface programming) and other agency technologies.However, dynamic proxy can only proxy interfaces and cannot represent ordinary classes.CGLIB achieves proxy by generating subclasses of the target class. In many cases, CGLIB is the best choice for dynamic proxy.This article will explore the working principle of the CGLIB FULL framework and its advantages in the development of Java.
working principle:
CGLIB achieves proxy by generating subclasses of the target class.It uses the ASM framework to operate the byte code of the target class.The following is a brief overview of the working principle of CGLIB:
1. Create an enhancer object:
Create an ENHANCER object, which is used to generate an instance of the proxy class.
2. Set the parent class:
Use the setsuperclass () method of the Enhancer object to set the target class to be proxy as the parent class.
3. Set back callback:
Set the callback function using the setcallback () method of the Enhancer object, that is, the logic of executing before and after the goal method execution.
4. Create proxy instance:
Create an instance of the proxy class with the Create () method of the enhancer object.
5. Call the proxy class method:
When calling the method of the proxy instance, CGLIB will implement the predefined logic through the MethodInterCector interface.
Advantage:
The CGLIB framework has many advantages in the development of Java. The following will introduce some important advantages in detail:
1. High performance:
Compared to the dynamic agent that comes with JDK, CGLIB is more efficient when generating proxy classes.Because the subclass of the target class is generated, the target method is not needed to call the target method, providing a faster execution speed.
2. Support non -interface agent:
CGLIB can not only proxy interfaces, but also as ordinary classes.This enables us to use the proxy function more flexibly.
3. Powerful function:
CGLIB provides rich functions, including method interception, field interception, etc., and can be customized as required.
4. No need to modify the source code:
Use the CGLIB proxy does not need to modify the source code, just dynamically generate the proxy class during runtime.
Example code:
Below is a simple example, showing how to use CGLIB to generate proxy categories:
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
class SampleClass {
public void doSomething() {
System.out.println("Original method");
}
}
class SampleClassInterceptor implements MethodInterceptor {
public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
System.out.println("Before method execution");
Object result = proxy.invokeSuper(obj, args);
System.out.println("After method execution");
return result;
}
}
public class CGLibExample {
public static void main(String[] args) {
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(SampleClass.class);
enhancer.setCallback(new SampleClassInterceptor());
SampleClass proxy = (SampleClass) enhancer.create();
proxy.doSomething();
}
}
In the above code, we created a SampleClass class and created a proxy SampleClassInterceptor.The proxy class adds additional logic before and after the execution of the proxy method.In an example, we set the proxy class to the parent class of SampleClass and set the callback function in the enhancer object.Eventually, an instance of the proxy class was created through the Create () method. Finally, when the Dosomething () method is called, the agent class will add additional logic before and after execution.
in conclusion:
CGLIB is a powerful code generation library that can be used to achieve dynamic agency and other agency technologies in Java development.By generating subclasses of the target class, CGLIB provides more efficient proxy implementation, supports non -interface agents, and has the ability to customize configuration.Although CGLIB may not be applicable under certain circumstances, in many scenes, it provides a high -performance, flexible and easy -to -use code generation solution.
