AOP切入点

通过AOP提供的切入点表达式，我们除了能在类，方法等位置指定切入点，还能在注解位置加入切入点。这样在我们添加注解的位置就会执行切面方法。

自定义注解

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@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface SystemLog {

    String actionType();

    String actionDescription();

    String functionName();

}

定义一个切入点

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@Pointcut(value = "@annotation(com.fizzy.core.annotation.SystemLog)")
private void logPointcut() {
}

定义一个切面方法

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@Before("logPointcut()")
private void beforeLog(JoinPoint joinPoint) throws ClassNotFoundException, NoSuchMethodException {
    SystemLog systemLog = ((MethodSignature)joinPoint.getSignature()).getMethod().getAnnotation(SystemLog.class);
    String actionName = systemLog.actionDescription();
    String actionType =systemLog.actionType();
    String functionName = systemLog.functionName();
    // 参数值
    Map<String, Object> params = getFields(joinPoint);
    System.out.println(actionName);
    System.out.println(actionType);
    System.out.println(functionName);
    System.out.println(params);
}

private static Map<String, Object> getFields(JoinPoint joinPoint) throws ClassNotFoundException, NoSuchMethodException {
    String classType = joinPoint.getTarget().getClass().getName();
    String methodName = joinPoint.getSignature().getName();
    Class<?>[] parameterTypes = ((MethodSignature) joinPoint.getSignature()).getMethod().getParameterTypes();
    ParameterNameDiscoverer pnd = new DefaultParameterNameDiscoverer();
    String[] parameterNames = pnd.getParameterNames(Class.forName(classType).getMethod(methodName, parameterTypes));
    Object[] args = joinPoint.getArgs();
    HashMap<String, Object> paramMap = new HashMap();
    for (int i = 0; i < Objects.requireNonNull(parameterNames).length; i++) {
        paramMap.put(parameterNames[i], args[i]);
    }
    return paramMap;
}

切入的代码加上注解

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@GetMapping("/findById")
@SystemLog(actionType = "query", actionDescription = "打开帖子详情", functionName = "postDetail")
public Post postDetail(@RequestParam int id) {
    return postService.findPostById(id);
}

结果

image-20220812161529313