java并发访问重复请求过滤问题

import static java.lang.annotation.ElementType.METHOD;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

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

import java.lang.reflect.Method;
import java.util.Set;
import java.util.concurrent.ConcurrentSkipListSet;

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;



@Aspect
@Component
public class NotDuplicateAop {

  private static final Set<String> KEY = new ConcurrentSkipListSet<>();

  @Pointcut("@annotation(com.hhly.skeleton.base.filter.NotDuplicate)")
  public void duplicate() {
  }

  /**
   * 对方法拦截后进行参数验证
   * @param pjp
   * @return
   * @throws Throwable
   */
  @Around("duplicate()")
  public Object duplicate(ProceedingJoinPoint pjp) throws Throwable {
    MethodSignature msig = (MethodSignature) pjp.getSignature();
    Method currentMethod = pjp.getTarget().getClass().getMethod(msig.getName(), msig.getParameterTypes());
    //拼接签名
    StringBuilder sb = new StringBuilder(currentMethod.toString());
    Object[] args = pjp.getArgs();
    for (Object object : args) {
      if(object != null){
        sb.append(object.getClass().toString());
        sb.append(object.toString());
      }
    }
    String sign = sb.toString();
    boolean success = KEY.add(sign);
    if(!success){
      throw new ServiceRuntimeException("该方法正在执行,不能重复请求");
    }
    try {
      return pjp.proceed();
    } finally {
      KEY.remove(sign);
    }

  }
}