common_helper/src/main/java/com/xiongyingqi/jackson/helper/ThreadJacksonMixInHolder.java
public static ObjectMapper builderMapper() {
        ThreadJacksonMixInHolder holder = holderThreadLocal.get();
        if (holder.mapper == null && isContainsMixIn()) {
            holder.mapper = new ObjectMapper();
            for (Map.Entry<Class<?>, Class<?>> mixIn : holder.mixIns) {
                holder.mapper.addMixInAnnotations(mixIn.getKey(), mixIn.getValue());
            }
        }
        clear();// 如果不调用clear可能导致线程内的数据是脏的！
        return holder.mapper;
    }
public static ObjectMapper builderMapper() {
        ThreadJacksonMixInHolder holder = holderThreadLocal.get();
        if (holder.mapper == null && isContainsMixIn()) {
            holder.mapper = new ObjectMapper();
            for (Map.Entry<Class<?>, Class<?>> mixIn : holder.mixIns) {
                holder.mapper.addMixInAnnotations(mixIn.getKey(), mixIn.getValue());
            }
        }
        clear();// 如果不调用clear可能导致线程内的数据是脏的！
        return holder.mapper;
    }
根据当前MixIn集合生成objectMapper<p>
<p>
<b>注意：该方法在返回mapper对象之后调用clear方法，如果再次调用builderMapper()肯定会保存</b>

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