@GetMapping("/{id}")
    public ShenyuAdminResult detailPolicy(@PathVariable("id")
                                          @Valid
                                          @Existed(provider = ScalePolicyMapper.class,
                                                  message = "scale policy is not existed") final String id) {
        ScalePolicyVO scalePolicyVO = scalePolicyService.findById(id);
        return Optional.ofNullable(scalePolicyVO)
                .map(item -> ShenyuAdminResult.success(ShenyuResultMessage.DETAIL_SUCCESS, item))
                .orElse(ShenyuAdminResult.error(ShenyuResultMessage.DETAIL_FAILED));
    }
detail scale policy.

@param id primary key
@return ShenyuAdminResult
shenyu-admin/src/main/java/org/apache/shenyu/admin/controller/ScalePolicyController.java