apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/InstanceService.java/InstanceService/getValidInstanceConfigDate
class InstanceService:  private Date getValidInstanceConfigDate() {
    Calendar cal = Calendar.getInstance();
    cal.add(Calendar.DATE, -1);
    cal.add(Calendar.HOUR, -1);
    return cal.getTime();
  }