Spring MethodInterceptor—— 轻松实现aop功能的三种方式

偏执的太偏执、 2023-07-15 09:12 9阅读 0赞

为下一篇日志链路追踪做铺垫先了解下AOP，这一块我就不用从新写了 基本可以看看这一篇  
原文链接：https://blog.csdn.net/u013905744/article/details/91364736

如果对于spring MethodInterceptor或spring aop概念不清楚，参考：[spring aop, spring interceptor, springmvc interceptor有什么区别？][spring aop_ spring interceptor_ springmvc interceptor]

以下是在spring boot环境下执行的

在spring boot下有两种方式设置AOP（实现织入weave）：

1. 使用@Aspect注解

2. 使用DefaultPointcutAdvisor

以实现TracingInterceptor为例

# 方法1：使用aspectj execution（切点） + interceptor（增强Advice）构成织入（DefaultPointcutAdvisor） #

interceptor

class TracingInterceptor implements MethodInterceptor { 
       Object invoke(MethodInvocation i) throws Throwable { 
       System.out.println( "method "+i.getMethod()+ " is called on "+ 
       i.getThis()+ " with args "+i.getArguments()); 
       Object ret=i.proceed(); 
       System.out.println( "method "+i.getMethod()+ " returns "+ret); 
       return ret; 
       } 
       }

织入配置类

@Configuration 
       public class InterceptorConfig { 
       
       public static final String traceExecution = "execution(* com.hfi.aop..*.*(..))"; 
       
       
       @Bean 
       public DefaultPointcutAdvisor defaultPointcutAdvisor2() { 
       TracingInterceptor interceptor = new TracingInterceptor(); 
       AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut(); 
       pointcut.setExpression(traceExecution); 
       
       // 配置增强类advisor 
       DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(); 
       advisor.setPointcut(pointcut); 
       advisor.setAdvice(interceptor); 
       return advisor; 
       } 
       }

效果：当执行到com.hfi.aop包下的方法，当执行performEncore方法

![20190610111918195.png][]

可以看到我们配置的TracingInterceptor生效了

# 方法2：使用自定义注解（切点）+interceptor（增强Advice）构成织入（DefaultPointcutAdvisor） #

自定义注解HfiTrace

@Target(ElementType.METHOD) 
       @Retention(RetentionPolicy.RUNTIME) 
       @Documented 
       public @interface HfiTrace { 
       }

interceptor

public class TracingInterceptor implements MethodInterceptor { 
       @Override 
       public Object invoke(MethodInvocation invocation) throws Throwable { 
       Method method = invocation.getMethod(); 
       HfiTrace annotation = getAnnotation(method); 
       if (annotation == null) { 
       return invocation.proceed(); 
       } 
       // 为什么调用http://127.0.0.1:8089/jpademo/perform时有两次输出呢？ 
       // 因为在Audience里面用的是@Around，会拦截到两次 
       System.out.println( "method " + invocation.getMethod() + " is called on " + invocation.getThis() + " with args" + 
       " " + invocation.getArguments()); 
       Object proceed = invocation.proceed(); 
       System.out.println( "method " + invocation.getMethod() + " returns " + proceed); 
       return proceed; 
       } 
       
       private HfiTrace getAnnotation(Method method) { 
       // 如果有多个annotation 似乎就不好用了 如放在controller上 由于已经有了@RequestMapping注解了 所以... 
       if (method.isAnnotationPresent(HfiTrace.class)) { 
       return method.getAnnotation(HfiTrace.class); 
       } 
       return null; 
       } 
       }

织入配置类

@Configuration 
       public class InterceptorAnnotationConfig { 
       
       @Bean 
       public DefaultPointcutAdvisor defaultPointcutAdvisor3() { 
       TracingInterceptor interceptor = new TracingInterceptor(); 
       
       // AnnotationMatchingPointcut pointcut = new AnnotationMatchingPointcut(HfiTrace.class, true); 
       JdkRegexpMethodPointcut pointcut = new JdkRegexpMethodPointcut(); 
       pointcut.setPatterns( "com.hfi.*"); 
       
       // 配置增强类advisor 
       DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(); 
       advisor.setPointcut(pointcut); 
       advisor.setAdvice(interceptor); 
       return advisor; 
       } 
       }

业务代码

@HfiTrace 
       @Override 
       public String perform() { 
       System.out.println( "perform..."); 
       return "perform"; 
       }

效果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTM5MDU3NDQ_size_16_color_FFFFFF_t_70][]

可以看到执行也是生效的

# 方法3：使用自定义注解（切点）+@Aspect（切面）构成织入 #

自定义注解HfiTrace

@Target(ElementType.METHOD) 
       @Retention(RetentionPolicy.RUNTIME) 
       @Documented 
       public @interface HfiTrace { 
       String name() default "默认注解信息"; 
       }

织入配置类

@Component 
       @Aspect 
       public class TracingAspect { 
       @Before( "@annotation(test)") 
       public void beforeTest(JoinPoint point, HfiTrace test){ 
       System.out.println( "method " + point.getSignature().getName() + " is called on " + point.getThis() + " with " + 
       "args" + 
       " " + point.getArgs()); 
       System.out.println( "before invoke: "+ test.name()); 
       } 
       
       @AfterReturning(value = "@annotation(test)", returning = "rvt") 
       public void afterTest(JoinPoint point, HfiTrace test, Object rvt) { 
       System.out.println( "method "+point.getSignature().getName() + " returns " + rvt); 
       System.out.println( "after invoke: " + test.name()); 
       } 
       }

业务代码：

controller层：

@HfiTrace 
       @GetMapping( "/perform") 
       public String perform() { 
       String perform = performance.perform(); 
       return perform; 
       } 
       
       @HfiTrace(name = "abc") 
       @GetMapping( "/performEncore") 
       public String performEncore() { 
       // 强制转换 
       Encoreable encoreable = (Encoreable) performance; 
       return encoreable.performEncore(); 
       }

service层：

@Component 
       public class PerformanceImpl implements Performance { 
       
       @HfiTrace 
       @Override 
       public String perform() { 
       System.out.println( "perform..."); 
       return "perform"; 
       } 
       }

效果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTM5MDU3NDQ_size_16_color_FFFFFF_t_70 1][]

综上：三种方式都可以实现相同的功能，方法3看起来最为简洁，只需要定义一个注解，然后写一个@Aspect切面类，就可以拦截指定方法的运行了

[spring aop_ spring interceptor_ springmvc interceptor]: https://blog.csdn.net/u013905744/article/details/91363203
[20190610111918195.png]: /images/20230528/a838474404d349cd9efd8ba8be885bbe.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTM5MDU3NDQ_size_16_color_FFFFFF_t_70]: /images/20230528/0d48d69a5c48435ebaa6dca96a7d9672.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTM5MDU3NDQ_size_16_color_FFFFFF_t_70 1]: /images/20230528/61302b76eb924a448479f6a733fe231c.png