@GetMapping("/tagId/{tagId}")
    public ShenyuAdminResult queryApiByTagId(@PathVariable("tagId") @Valid final String tagId) {
        List<TagRelationDO> tagRelationDOS = Optional.ofNullable(tagRelationService.findByTagId(tagId)).orElse(Lists.newArrayList());
        return ShenyuAdminResult.success(ShenyuResultMessage.DETAIL_SUCCESS, tagRelationDOS);
    }
list tag relation.

@param tagId tag tagId.
@return {@linkplain ShenyuAdminResult}
shenyu-admin/src/main/java/org/apache/shenyu/admin/controller/TagRelationController.java