Detailed explanation of cutting programming technology in the aspectj weaver framework
Detailed explanation of cutting programming technology in the aspectj weaver framework
Overview:
Cutting surface programming is a programming mode that separates cross -sectional attention and independent of the main business logic.ASPECTJ Weaver is the compiler and execution engine of Aspectj programming language. It can be used with Java language to achieve surface programming.This article will introduce the cutting surface programming technology in the ASPECTJ Weaver framework, and provide some Java code examples to help readers better understand.
1. Cutting surface programming foundation
1.1 Noodles and attention points
ASPECT indicates that the cross -sectional focus of the business logic is independent, such as log records, performance monitoring, transaction management, etc.Concern refers to a specific behavior that spans multiple objects in the application, such as method calls, abnormal processing, etc.
1.2 Inbound point and connection point
PointCut is an expression that defines which connection points (Join Point) in the application should be processed.The connection point is a specific location in the application, such as when the method is called, when the abnormality is thrown, etc.
2. Aspectj Weaver framework basis
2.1 Installation and configuration
First, download and install the latest version of the Aspectj Weaver framework.Then add the jar file of Aspectj to the class path of the Java project.You can manage these dependencies from the construction tool (such as Maven or Gradle).
2.2 Aspectj syntax
Aspectj uses an annotated syntax to declare the cut surface and entry point and enhanced behavior.Below is a simple Aspectj cutting example:
@Aspect
public class LoggingAspect {
@Pointcut("execution(* com.example.service.*.*(..))")
public void serviceMethods() {}
@Before("serviceMethods()")
public void beforeServiceMethod(JoinPoint joinPoint) {
System.out.println("Executing " + joinPoint.getSignature());
}
@After("serviceMethods()")
public void afterServiceMethod(JoinPoint joinPoint) {
System.out.println("Finished executing " + joinPoint.getSignature());
}
}
In the above example, loggingaspect is a cut -off definition class that uses @Aspect annotations for identification.The serviceMethods () method defines an entry point, indicating any method in the com.example.service package.BeForeServiceMethod () and AfterserviceMethod () methods are used to perform enhanced behaviors before and after the entry point.
2.3 Compilation and operation
To compile the ASPECTJ surface, you can use the AJC command line tool, or use the ASPECTJ plug -in provided by IDE (such as Eclipse).After compiling, ASPECTJ will woven the cut surface into the target code.
When running a program containing ASPECTJ surface, you need to ensure that the jar file of the Aspectj Weaver framework is located in the class path.Only in this way can the cut surface act properly on the target code.
Third, cut surface programming application scenarios
Cutting programming is widely used in the following aspects:
3.1 log record
By adding log logic to the cut surface, you can easily obtain the detailed information of the program when runtime, such as method calls, parameters, and return values.
3.2 Performance monitoring
The cut surface can be used for the execution time of the capture method, so as to evaluate the performance of the program and find the potential performance bottleneck.
3.3 transaction management
Using cutting management transactions can simplify the code and ensure the consistency and atomicity of the affairs during the implementation of the method.
Fourth, summary
This article details the cutting programming technology in the Aspectj Weaver framework.The cut -off programming points are independent of the cross -cutting point and the main business logic, which can decouple the different attention points in the program, thereby improving the maintenance and testability of the code.Aspectj Weaver provides rich grammar and tools that can easily implement cutting programming.
