package com.yami.trading.service.contract; import cn.hutool.core.collection.ConcurrentHashSet; import java.util.HashSet; import java.util.Set; public class ContractLock { private static final Set filter = new ConcurrentHashSet<>(); public static synchronized boolean add(String order_no) { if (!filter.add(order_no)) { return false; } else { return true; } } public static void remove(String order_no) { filter.remove(order_no); } }