apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/spi/defaultimpl/DefaultRolePermissionService.java/DefaultRolePermissionService/queryUsersWithRole
class DefaultRolePermissionService:    public Set<UserInfo> queryUsersWithRole(String roleName) {
        Role role = findRoleByRoleName(roleName);

        if (role == null) {
            return Collections.emptySet();
        }

        List<UserRole> userRoles = userRoleRepository.findByRoleId(role.getId());

        return userRoles.stream().map(userRole -> {
            UserInfo userInfo = new UserInfo();
            userInfo.setUserId(userRole.getUserId());
            return userInfo;
        }).collect(Collectors.toSet());
    }