apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/config/BizConfig.java/BizConfig/itemValueLengthLimit
class BizConfig:  public int itemValueLengthLimit() {
    int limit = getIntProperty("item.value.length.limit", DEFAULT_ITEM_VALUE_LENGTH);
    return checkInt(limit, 5, Integer.MAX_VALUE, DEFAULT_ITEM_VALUE_LENGTH);
  }