Spring源碼系列：SpringAop中的NameMatchMethodPointcutAdvisor和RegexpMethodPointcutAdvisor

上一節我們講到了SpringAop基於註解版本的織入和創建代理的流程。這一節我們來講兩個切面類。從前面知道一個切面是有兩部分構成增強和切點。上節我們也列舉了一些常用的切面下面我們就來
介紹兩個功能比較相近的切面類。

NameMatchMethodPointcutAdvisor的使用

啓動配置類


@SpringBootApplication
public class App {
  public static void main(String[] args) {
    SpringApplication application = new SpringApplicationBuilder(App.class).application();
    ApplicationContext context = application.run(args);
    UserService userServiceImpl = (UserService)context.getBean("userServiceImpl");
    userServiceImpl.findUser();
    
  }
  @Configuration
  public static class AppConfig{
    /**
     * 定義切面
     * @return
     */
    @Bean
    public MethodBeforeAdvice methodBeforeAdvice(){
      return new com.coledy.aop.advice.MethodBeforeAdvice();
    }
    /**
     * 創建一個NameMatchMethodPointcutAdvisor 切面
     * @return
     */
    @Bean
    public NameMatchMethodPointcutAdvisor nameMatchMethodPointcutAdvisor(){
      NameMatchMethodPointcutAdvisor matchMethodPointcutAdvisor = new NameMatchMethodPointcutAdvisor();
      matchMethodPointcutAdvisor.setAdvice(methodBeforeAdvice());
      matchMethodPointcutAdvisor.setMappedNames("find*");
      return matchMethodPointcutAdvisor;
    }
  }
}

被代理對象和增強

public interface UserService {
  void findUser();
}

@Component
public class UserServiceImpl implements UserService {
  @Override
  public void findUser() {
    System.out.println("findUser....");
  }
}

public class MethodBeforeAdvice implements org.springframework.aop.MethodBeforeAdvice {
  @Override
  public void before(Method method, Object[] args, Object target) throws Throwable {
    System.out.println("我是一個前置增強 ");
  }
}

啓動app 輸出
我是一個前置增強
findUser…

可以看到到這裏我們看到了我們想要看到的結果。對象被代理了。值得注意的是NameMatchMethodPointcutAdvisor這個切面類的setMappedNames 需要配置的是方法名字。支持通配符。

RegexpMethodPointcutAdvisor的使用

我們只在上面的例子的基礎上加一個後置增強和一個切面配置

@SpringBootApplication
//@Import(RegisterAspectJAutoProxyRegisterar.class)
public class App {

  public static void main(String[] args) {
    SpringApplication application = new SpringApplicationBuilder(App.class).application();
    ApplicationContext context = application.run(args);
    UserService userServiceImpl = (UserService)context.getBean("userServiceImpl");
    userServiceImpl.findUser();
  }
  @Configuration
  public static class AppConfig{
 
   @Bean
    public MethodBeforeAdvice methodBeforeAdvice(){
      return new com.coledy.aop.advice.MethodBeforeAdvice();
    }
    @Bean
    public RegexpMethodPointcutAdvisor regexpMethodPointcutAdvisor(){
      RegexpMethodPointcutAdvisor regexpMethodPointcutAdvisor = new RegexpMethodPointcutAdvisor();
      regexpMethodPointcutAdvisor.setPatterns("*.findGoods");
      regexpMethodPointcutAdvisor.setAdvice(methodBeforeAdvice());
      return regexpMethodPointcutAdvisor;
    }
  }
}

public class CommonMethodAfterAdvice implements AfterReturningAdvice {

  @Override
  public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
    System.out.println("common after return");

  }
}

同樣也達到了代理的目的。下面我們就看一下爲什麼我們只是簡單的在容器中定義了一個切面 Spring就幫我們織入了被代理的對象裏面。

SpringAop非註解式的源碼分析

看過上一篇文章的應該有印象 getAdvicesAndAdvisorsForBean 這個方法是AbstractAutoProxyCreator類唯一一個留給子類必須實現的方法（獲取所有的切面由於不同子類的實現獲取切面的方式不同所以這裏交給了子類實現模板方法。如BeanNameAutoProxyCreator就和我們經常使用的AnnotationAwareAspectJAutoProxyCreator 這個織入類的實現方式不一樣）。

	protected Object[] getAdvicesAndAdvisorsForBean(
			Class<?> beanClass, String beanName, @Nullable TargetSource targetSource) {
		
		List<Advisor> advisors = findEligibleAdvisors(beanClass, beanName);
		if (advisors.isEmpty()) {
			return DO_NOT_PROXY;
		}
		return advisors.toArray();
	}

跟進findEligibleAdvisors


	protected List<Advisor> findEligibleAdvisors(Class<?> beanClass, String beanName) {
		List<Advisor> candidateAdvisors = findCandidateAdvisors();
		List<Advisor> eligibleAdvisors = findAdvisorsThatCanApply(candidateAdvisors, beanClass, beanName);
		extendAdvisors(eligibleAdvisors);
		if (!eligibleAdvisors.isEmpty()) {
			eligibleAdvisors = sortAdvisors(eligibleAdvisors);
		}
		return eligibleAdvisors;
	}


//這裏爲了節省篇幅 直接跳到findCandidateAdvisors這個方法裏面來 我們上一節說過 AnnotationAwareAspectJAutoProxyCreator 重寫了這個方法
//但是在子類的方法有行代碼很關鍵List<Advisor> advisors = super.findCandidateAdvisors();
//先回去父類獲取Advisor 然後再用自己的邏輯獲取 父類是獲取實現了Advisor接口的切面 
//子類是獲取有AspectJ註解的並且方法中有@Pointcut的方法 封裝成切面。
	protected List<Advisor> findCandidateAdvisors() {
		Assert.state(this.advisorRetrievalHelper != null, "No BeanFactoryAdvisorRetrievalHelper available");
		return this.advisorRetrievalHelper.findAdvisorBeans();
	}

下面我們繼續看看父類獲取Advisor的邏輯。其實和子類的獲取邏輯很類似。父類的這個更簡單因爲本來就是Advisor不需要解析包裝。

public List<Advisor> findAdvisorBeans() {
		String[] advisorNames = this.cachedAdvisorBeanNames;
		if (advisorNames == null) {
		    //獲取beanFactory中實現了Advisor接口的實例
			advisorNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors(
					this.beanFactory, Advisor.class, true, false);
			this.cachedAdvisorBeanNames = advisorNames;
		}
		if (advisorNames.length == 0) {
			return new ArrayList<>();
		}

		List<Advisor> advisors = new ArrayList<>();
		for (String name : advisorNames) {
			if (isEligibleBean(name)) {
   			     //判斷當前bean是不是正在創建。 正在創建則不做任何處理。這裏需要注意的是 即使當前正在
   			     //創建的bean是Advisor的子類 也不必擔心 這個類無法加入到advisors中因爲這個方法不止調用一次。每一個bean實例化的時候都會調用。
				if (this.beanFactory.isCurrentlyInCreation(name)) {
					if (logger.isTraceEnabled()) {
						logger.trace("Skipping currently created advisor '" + name + "'");
					}
				}
				else {
					try {
					   //這裏如果沒有創建就從beanFactory獲取bean 如果沒創建會創建 繼而加入進緩存中
					   //bean的創建流程請參考https://blog.csdn.net/xiaomujiang_dafangzi/article/details/105183005
						advisors.add(this.beanFactory.getBean(name, Advisor.class));
					}
					catch (BeanCreationException ex) {
						Throwable rootCause = ex.getMostSpecificCause();
						if (rootCause instanceof BeanCurrentlyInCreationException) {
							BeanCreationException bce = (BeanCreationException) rootCause;
							String bceBeanName = bce.getBeanName();
							if (bceBeanName != null && this.beanFactory.isCurrentlyInCreation(bceBeanName)) {
								if (logger.isTraceEnabled()) {
									logger.trace("Skipping advisor '" + name +
											"' with dependency on currently created bean: " + ex.getMessage());
								}
								// Ignore: indicates a reference back to the bean we're trying to advise.
								// We want to find advisors other than the currently created bean itself.
								continue;
							}
						}
						throw ex;
					}
				}
			}
		}
		return advisors;
	}

到這裏查找的過程就完了、、其實還是很簡單的，就是如果有實現Advisor接口的類。至於是如何織入到代理類中的請參考上一篇https://blog.csdn.net/xiaomujiang_dafangzi/article/details/105217189

Spring源碼系列：SpringAop中的NameMatchMethodPointcutAdvisor和RegexpMethodPointcutAdvisor

目錄

NameMatchMethodPointcutAdvisor的使用

RegexpMethodPointcutAdvisor的使用

SpringAop非註解式的源碼分析

985 碩士程序員，空窗 4 個月沒有 Offer！

賽博鬥地主——使用大語言模型扮演Agent智能體玩牌類遊戲。

VScode右鍵打開(添加到右鍵)

Spring源碼系列：SpringAop中的NameMatchMethodPointcutAdvisor和RegexpMethodPointcutAdvisor

SpringBoot源碼系列:Environment機制深入分析（一）

springboot源碼系列-HandlerMapping

springboot源碼系列-HandlerMapping（2）

spring 解決@JsonProperty設置不生效

Mac下配置sublime實現LaTeX

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

linux以太網驅動總結