Spring 检查数据库中是否存在团队或输入字段是否为空

有必要检查Team的输入字段是否为空，以及存储库中是否有这样的团队

如果字段不是空的，并且没有这样的团队，那么您可以创建一个新团队。如果字段为空或团队已存在，则给出一个错误

管理员控制器

@Controller
public class AdminController {
   @RequestMapping(value = "/admin/team", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
    public String addTeam(Model model, @ModelAttribute("teamForm") @Validated TeamForm teamForm,
            BindingResult result, final RedirectAttributes redirectAttributes) {
        System.out.println("addTeam invoked");
        if (result.hasErrors()) {
            return "/admin";
        }
        Team newTeam = new Team();
        newTeam.setName(teamForm.getName());
        newTeam.setUrl(teamForm.getUrl());
        teamRepository.save(newTeam);
        return "teamList";
    }
 @RequestMapping(value = "/admin", method = RequestMethod.GET)
    public String adminPage(Model model) {
        model.addAttribute("teamForm",new TeamForm());
        model.addAttribute("eventForm",new EventForm());
        model.addAttribute("usersForm",new UsersForm());
        return "admin";
    }

admin.html

      <form th:action="@{/admin/team}"
        th:object="${teamForm}" method="POST">
      Team name:
      <input type="text" th:field="*{name}" />
          <p th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Incorrect Name</p>
      <br/>
      Url :
      <input type="text" th:field="*{url}" />
      <br/>
      <input type="submit" value="Create Team" />
  </form>

团队名称：
名称不正确


网址：