spring aop可以建议哪种方法，或者spring aop连接点的限制是什么？

Question

我正在使用spring aop，但发现有3种情况，但我不太清楚：情况1：一个没有实现或扩展任何类或接口的类在这种情况下，任何非私有方法都将成为连接点

情况2：一个类实现一个接口并实现方法在此结果中，仅在interface中声明的方法将是连接点

情况3：一个类扩展了超类并覆盖了超类的方法在这种缝合中，所有子类的方法都不会成为连接点。

弹簧aop是如何设计的？

这是我使用的代码：

JdkProxyInterface.java

package com.example.proxytestdemo;

public interface JdkProxyInterface {

    void function(int i);
}

JdkProxy.java

package com.example.proxytestdemo;
import org.springframework.stereotype.Component;

@Component
public class JdkProxy implements JdkProxyInterface {

    @Override
    @TimeIt
    public void function(int i) {
        System.out.println("JdkProxy function");
    }

    @TimeIt
    public void function1(int i) {
        System.out.println("JdkProxy function");
    }

    @TimeIt
    public void function2(int i) {
        System.out.println("JdkProxy function");
    }

}

SubJdkProxy.java

package com.example.proxytestdemo;

import org.springframework.stereotype.Component;

@Component
public class SubJdkProxy extends JdkProxy {

    @TimeIt
    public void functionSubJdkProxy(int i) {
        System.out.println("functionSubJdkProxy");
    }
}

TimeIt.java

package com.example.proxytestdemo;
import java.lang.annotation.*;

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE,ElementType.METHOD})
@Inherited
public @interface TimeIt {
    boolean enabled() default true;
}

TimePointCut.java

package com.example.proxytestdemo;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;


@Aspect
@Component
public class TimePointCut {

    @Pointcut("execution(* com.example.proxytestdemo..*(..))")
    public void calcTime1() {
    }

    @Around(value = "calcTime1()")
    public Object aspectProcess(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("proxy begin....... ");
        MethodSignature signature = (MethodSignature) pjp.getSignature();
        Method method = signature.getMethod();
        TimeIt annotation = method.getAnnotation(com.example.proxytestdemo.TimeIt.class);
        if (annotation == null) {
            annotation = pjp.getTarget().getClass().getAnnotation(TimeIt.class);
            if (annotation == null) {
                for (Class<?> cls : pjp.getClass().getInterfaces()) {
                    annotation = cls.getAnnotation(TimeIt.class);
                    if (annotation != null) {
                        break;
                    }
                }
            }
        }
        if (annotation != null) {
            System.out.println(annotation.enabled());
        }
        Object o = null;
        long t1 = 0, t2 = 0;
        try {
            t1 = System.currentTimeMillis();
            o = pjp.proceed();
            t2 = System.currentTimeMillis();
        } catch (Exception e) {
            throw e;
        } finally {
            System.out.println("proxy end....... ");
            System.out.println("time cost: "+ (t2-t1)/1000 + "s");
        }

        return o;
    }
}

我发现不建议使用JdkProxy.function1（）和JdkProxy.function2（）以及SubJdkProxy.functionSubJdkProxy（）。

Answer 1

您的应用程序应该可以运行。看，我尝试了各种组合，它们都起作用：

驱动程序应用程序：

package com.example.proxytestdemo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

@SpringBootApplication
public class Application {
  public static void main(String[] args) {
    try (ConfigurableApplicationContext context = SpringApplication.run(Application.class, args)) {
      doStuff(context);
    }
  }

  private static void doStuff(ConfigurableApplicationContext context) {
    JdkProxy jdkProxy = (JdkProxy) context.getBean("jdkProxy");
    jdkProxy.function(11);
    jdkProxy.function1(22);
    jdkProxy.function2(33);
    System.out.println("----------");

    JdkProxyInterface jdkProxyInterface = jdkProxy ;
    jdkProxyInterface.function(11);
    System.out.println("==========");

    SubJdkProxy subJdkProxy = (SubJdkProxy) context.getBean("subJdkProxy");
    subJdkProxy.function(11);
    subJdkProxy.function1(22);
    subJdkProxy.function2(33);
    subJdkProxy.functionSubJdkProxy(44);
    System.out.println("----------");

    jdkProxyInterface = subJdkProxy;
    jdkProxyInterface.function(11);
  }
}

控制台日志：

execution(void com.example.proxytestdemo.JdkProxy.function(int))
JdkProxy function
execution(void com.example.proxytestdemo.JdkProxy.function1(int))
JdkProxy function
execution(void com.example.proxytestdemo.JdkProxy.function2(int))
JdkProxy function
----------
execution(void com.example.proxytestdemo.JdkProxy.function(int))
JdkProxy function
==========
execution(void com.example.proxytestdemo.JdkProxy.function(int))
JdkProxy function
execution(void com.example.proxytestdemo.JdkProxy.function1(int))
JdkProxy function
execution(void com.example.proxytestdemo.JdkProxy.function2(int))
JdkProxy function
execution(void com.example.proxytestdemo.SubJdkProxy.functionSubJdkProxy(int))
functionSubJdkProxy
----------
execution(void com.example.proxytestdemo.JdkProxy.function(int))
JdkProxy function

顺便说一句，为了专注于基础知识，我将您方面的建议方法简化为：
      @Around(value = "calcTime1()")
      public Object aspectProcess(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println(pjp);
        return pjp.proceed();
      }