private List<SelectorVO> buildSelectorExportVOList(final List<SelectorDO> selectorDOList) {
        Map<String, String> idMap = ListUtil.toMap(selectorDOList, SelectorDO::getId, SelectorDO::getPluginId);
        if (MapUtils.isEmpty(idMap)) {
            return new ArrayList<>();
        }
        Map<String, List<SelectorConditionDO>> selectorConditionMap = ListUtil.groupBy(selectorConditionMapper.selectBySelectorIds(idMap.keySet()), SelectorConditionDO::getSelectorId);

        Map<String, PluginDO> pluginDOMap = ListUtil.toMap(pluginMapper.selectByIds(Lists.newArrayList(idMap.values())), PluginDO::getId);

        return Optional.ofNullable(selectorDOList).orElseGet(ArrayList::new)
                .stream()
                .filter(Objects::nonNull)
                .map(selectorDO -> {
                    String id = selectorDO.getId();
                    String pluginId = selectorDO.getPluginId();
                    PluginDO pluginDO = pluginDOMap.get(pluginId);
                    if (Objects.isNull(pluginDO)) {
                        return null;
                    }
                    List<SelectorConditionVO> selectorConditionList = SelectorConditionVO.buildSelectorConditionVOList(selectorConditionMap.get(id));
                    SelectorVO selectorExportVO = SelectorVO.buildSelectorVO(selectorDO);
                    selectorExportVO.setSelectorConditions(selectorConditionList);
                    return selectorExportVO;
                })
                .filter(Objects::nonNull)
                .collect(Collectors.toList());
    }
the plugin delete, synchronously delete selectors.

@param event event
shenyu-admin/src/main/java/org/apache/shenyu/admin/service/impl/SelectorServiceImpl.java