apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/entity/InstanceConfig.java/InstanceConfig/prePersist
class InstanceConfig:  @PrePersist
  protected void prePersist() {
    if (this.dataChangeCreatedTime == null) {
      dataChangeCreatedTime = new Date();
    }
    if (this.dataChangeLastModifiedTime == null) {
      dataChangeLastModifiedTime = dataChangeCreatedTime;
    }
  }