Spring AOP pre-notification and post-notification

• To add a jar package:

• To include the AOP namespace in the configuration file

• Annotation-based annotations are described in the following configuration file:

Beans-aop-helloworld.xml

<?xml version= "1.0" encoding= "UTF-8"? ><beans xmlns= "Http://www.springframework.org/schema/beans" xmlns: Xsi= "Http://www.w3.org/2001/XMLSchema-instance" xmlns:aop= "Http://www.springframework.org/schema/aop" xmlns: context= "Http://www.springframework.org/schema/context" xsi:schemalocation= "http://www.springframework.org/ Schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/ AOP Http://www.springframework.org/schema/aop/spring-aop-4.2.xsdhttp://www.springframework.org/schema/context Http://www.springframework.org/schema/context/spring-context-4.2.xsd ">    <!--Configuration Auto-Scan Package--    < Context:component-scan base-package= "Spring.aop.helloworld" ></context:component-scan>        <!-- ASPECTJ Annotations Work: Automatically generate proxy objects for matching classes--    <aop:aspectj-autoproxy></aop:aspectj-autoproxy></beans >

• To abstract the code of crosscutting concerns into a class of facets
  • The slice is first a bean in the IOC, which joins the @component annotation
  • Facets also need to be added to @aspect annotations:
• Declare various notifications in the class:
• Affirm a method
• Add @before annotations before the method
• You can declare a parameter of type jointpoint in the notification method, and then access the link details on Eng. such as the method name and the parameter value.
• The specific code is as follows:
  • Arithmeticcalculator.java

Package Spring.aop.helloworld;public interface Arithmeticcalculator {public int add (int i, Int. j);p Ublic int sub (int i, in T j);p ublic int mul (int i, int j);p ublic int div (int i, int j);}

• • Arithmeticcalculatorimpl.java

Package Spring.aop.helloworld;import org.springframework.stereotype.Component; @Componentpublic class  Arithmeticcalculatorimpl implements Arithmeticcalculator {@Overridepublic int add (int i, int j) {int result = i + J;return Result;} @Overridepublic int sub (int i, int j) {int result = I-j;return result;} @Overridepublic int mul (int i, int j) {int result = i * j;return result;} @Overridepublic int div (int i, int j) {int result = I/j;return result;}}

• • Loggingaspect.java

Package Spring.aop.helloworld;

Import Java.util.Arrays;
Import java.util.List;

Import Org.aspectj.lang.JoinPoint;
Import Org.aspectj.lang.annotation.After;
Import Org.aspectj.lang.annotation.Aspect;
Import Org.aspectj.lang.annotation.Before;
Import org.springframework.stereotype.Component;

Declare this class as a tangent: you need to put the class in an IOC container and declare it as a tangent plane
@Aspect
@Component
public class Loggingaspect {
Declares that the method is a pre-notification: Executes before the target method starts
@Before ("Execution (public int spring.aop.helloworld.arithmeticcalculator.* (int, int))")
public void Beforemethod (Joinpoint joinpoint) {
String methodName = Joinpoint.getsignature (). GetName ();
list<object> args = Arrays.aslist (Joinpoint.getargs ());
System.out.println ("the" + MethodName + "begins" + "args is:" + args);
}

Post notification: Executes after the target method has occurred (regardless of whether the method has an exception)
The sea cannot access the results of the target method execution in the post notification
@After ("Execution (public int spring.aop.helloworld.arithmeticcalculator.* (int, int))")
public void Aftermethod (Joinpoint joinpoint) {
String methodName = Joinpoint.getsignature (). GetName ();
list<object> args = Arrays.aslist (Joinpoint.getargs ());
System.out.println ("the" + MethodName + "ends" + methodName + "args is:" + args);
}
}

• Note: There are several ways to match the Execute function, as follows:

Represents any return value execution (public * spring.aop.helloworld.arithmeticcalculator.* (int, int))//means all classes in the package execution (public * spring.aop.helloworld.*.* (int, int))//Match all public methods of the Arithmetriccalculator interface Execution (Common * arithmeticcalculator.* ( ...)) The method that matches the value returned in the Arithmetriccalculator interface for double type execute public double arithmetricclaculator.* (...) With a method with the first argument of type double, ... Match any number of arguments of any type execution public double arithmetriccalculator.* (double, ...) Method execution public double arithmetriccalculator.* the match parameter type is double, double (double)

　　

Spring AOP pre-notification and post-notification