Java 如果发生错误，Thymeleaf Spring th:block和th:each不会再次运行

我正在验证定义角色名称的字段。这是一种通过邮寄的形式。关键是当发生错误并再次调用时：

modelAndView.setViewName ("admin/role");
return modelAndView;

它不会在

th:block

中重新生成

列表。但当这个过程正确完成时，它会显示我的正常页面

成功流程：

@RequestMapping(value = "/admin/role", method = RequestMethod.GET)
public ModelAndView role(Model model){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    List<Page> pages = pageService.getAllPages();
    Role role = new Role();
    modelAndView.addObject("role", role);
    modelAndView.addObject("pages", pages);
    modelAndView.addObject("userName", user.getName());
    modelAndView.setViewName("admin/role");
    return modelAndView;
}

@RequestMapping(value = "/admin/role", method = RequestMethod.POST)
public ModelAndView createNewRole(@Valid Role role,BindingResult bindingResult,
                                  @RequestParam(value = "pgids" , required = false) Integer [] pgids
                                  ){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    modelAndView.addObject("userName", user.getName());

    Role roleExist = roleService.findByAuthority(role.getAuthority());
    if (roleExist != null){
        bindingResult
                .rejectValue("authority","error.app_role", "There is already a role registered with the name provided");
    }
    if (bindingResult.hasErrors()){
            modelAndView.setViewName("admin/role");
    }else{
        if(pgids != null) {
            for (int i = 0; i < pgids.length; i++) {
                System.out.println(pgids[i]);
            }
        }
        roleService.saveRole(role, pgids);

        List<Page> pages = pageService.getAllPages();
        modelAndView.addObject("successMessage", "Role has been created successfully");
        modelAndView.addObject("role", new Role());
        modelAndView.addObject("pages", pages);
        modelAndView.setViewName("admin/role");
    }
    return modelAndView;
}

如果发生错误：

@RequestMapping(value = "/admin/role", method = RequestMethod.GET)
public ModelAndView role(Model model){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    List<Page> pages = pageService.getAllPages();
    Role role = new Role();
    modelAndView.addObject("role", role);
    modelAndView.addObject("pages", pages);
    modelAndView.addObject("userName", user.getName());
    modelAndView.setViewName("admin/role");
    return modelAndView;
}

@RequestMapping(value = "/admin/role", method = RequestMethod.POST)
public ModelAndView createNewRole(@Valid Role role,BindingResult bindingResult,
                                  @RequestParam(value = "pgids" , required = false) Integer [] pgids
                                  ){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    modelAndView.addObject("userName", user.getName());

    Role roleExist = roleService.findByAuthority(role.getAuthority());
    if (roleExist != null){
        bindingResult
                .rejectValue("authority","error.app_role", "There is already a role registered with the name provided");
    }
    if (bindingResult.hasErrors()){
            modelAndView.setViewName("admin/role");
    }else{
        if(pgids != null) {
            for (int i = 0; i < pgids.length; i++) {
                System.out.println(pgids[i]);
            }
        }
        roleService.saveRole(role, pgids);

        List<Page> pages = pageService.getAllPages();
        modelAndView.addObject("successMessage", "Role has been created successfully");
        modelAndView.addObject("role", new Role());
        modelAndView.addObject("pages", pages);
        modelAndView.setViewName("admin/role");
    }
    return modelAndView;
}

获取方法：

@RequestMapping(value = "/admin/role", method = RequestMethod.GET)
public ModelAndView role(Model model){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    List<Page> pages = pageService.getAllPages();
    Role role = new Role();
    modelAndView.addObject("role", role);
    modelAndView.addObject("pages", pages);
    modelAndView.addObject("userName", user.getName());
    modelAndView.setViewName("admin/role");
    return modelAndView;
}

@RequestMapping(value = "/admin/role", method = RequestMethod.POST)
public ModelAndView createNewRole(@Valid Role role,BindingResult bindingResult,
                                  @RequestParam(value = "pgids" , required = false) Integer [] pgids
                                  ){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    modelAndView.addObject("userName", user.getName());

    Role roleExist = roleService.findByAuthority(role.getAuthority());
    if (roleExist != null){
        bindingResult
                .rejectValue("authority","error.app_role", "There is already a role registered with the name provided");
    }
    if (bindingResult.hasErrors()){
            modelAndView.setViewName("admin/role");
    }else{
        if(pgids != null) {
            for (int i = 0; i < pgids.length; i++) {
                System.out.println(pgids[i]);
            }
        }
        roleService.saveRole(role, pgids);

        List<Page> pages = pageService.getAllPages();
        modelAndView.addObject("successMessage", "Role has been created successfully");
        modelAndView.addObject("role", new Role());
        modelAndView.addObject("pages", pages);
        modelAndView.setViewName("admin/role");
    }
    return modelAndView;
}

@RequestMapping（value=“/admin/role”，method=RequestMethod.GET）
公共模型和视图角色（模型）{
ModelAndView ModelAndView=新建ModelAndView（）；
Authentication auth=SecurityContextHolder.getContext（）.getAuthentication（）；
User=userService.findUserByEmail（auth.getName（））；
List pages=pageService.getAllPages（）；
角色=新角色（）；
添加对象（“角色”，角色）；
添加对象（“页面”，页面）；
modelAndView.addObject（“用户名”，user.getName（））；
modelAndView.setViewName（“管理员/角色”）；
返回模型和视图；
}

发布方法：

@RequestMapping(value = "/admin/role", method = RequestMethod.GET)
public ModelAndView role(Model model){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    List<Page> pages = pageService.getAllPages();
    Role role = new Role();
    modelAndView.addObject("role", role);
    modelAndView.addObject("pages", pages);
    modelAndView.addObject("userName", user.getName());
    modelAndView.setViewName("admin/role");
    return modelAndView;
}

@RequestMapping(value = "/admin/role", method = RequestMethod.POST)
public ModelAndView createNewRole(@Valid Role role,BindingResult bindingResult,
                                  @RequestParam(value = "pgids" , required = false) Integer [] pgids
                                  ){
    ModelAndView modelAndView = new ModelAndView();
    Authentication auth = SecurityContextHolder.getContext().getAuthentication();
    User user = userService.findUserByEmail(auth.getName());
    modelAndView.addObject("userName", user.getName());

    Role roleExist = roleService.findByAuthority(role.getAuthority());
    if (roleExist != null){
        bindingResult
                .rejectValue("authority","error.app_role", "There is already a role registered with the name provided");
    }
    if (bindingResult.hasErrors()){
            modelAndView.setViewName("admin/role");
    }else{
        if(pgids != null) {
            for (int i = 0; i < pgids.length; i++) {
                System.out.println(pgids[i]);
            }
        }
        roleService.saveRole(role, pgids);

        List<Page> pages = pageService.getAllPages();
        modelAndView.addObject("successMessage", "Role has been created successfully");
        modelAndView.addObject("role", new Role());
        modelAndView.addObject("pages", pages);
        modelAndView.setViewName("admin/role");
    }
    return modelAndView;
}

@RequestMapping（value=“/admin/role”，method=RequestMethod.POST）
public ModelAndView createNewRole（@Valid Role Role、BindingResult、BindingResult、，
@RequestParam（value=“pgids”，required=false）整数[]pgids
){
ModelAndView ModelAndView=新建ModelAndView（）；
Authentication auth=SecurityContextHolder.getContext（）.getAuthentication（）；
User=userService.findUserByEmail（auth.getName（））；
modelAndView.addObject（“用户名”，user.getName（））；
Role roleExist=roleService.findByAuthority（Role.getAuthority（））；
if（roleExist！=null）{
绑定结果
.rejectValue（“authority”、“error.app_role”、“已使用提供的名称注册了一个角色”）；
}
if（bindingResult.hasErrors（））{
modelAndView.setViewName（“管理员/角色”）；
}否则{
如果（pgids！=null）{
对于（int i=0；i

HTML表单

<form autocomplete="off" action="#" th:action="@{/admin/role}" method="post" role="form">
<div class="row">
    <div class="col-md-12 bottommargin-sm">
        <label>Name of the Role</label>
        <label class="errormsg" th:if="${#fields.hasErrors('role.authority')}" th:errors="${role.authority}"></label>
        <input type="text" th:field="${role.authority}" class="sm-form-control"
               placeholder="Example Name"/>
    </div>
    <div class="col-md-12">
        <label>Catalogue of Pages</label>
        <table class="table table-hover">
            <thead>
            <tr>
                <th class="col-sm-2 center">Asign</th>
                <th class="col-sm-4 center">Name</th>
                <th class="col-sm-6 center">URL</th>
            </tr>
            </thead>
            <tbody>
            <th:block th:each="page : ${pages}">
                <tr>
                    <td class="col-sm-2 center">
                        <input type="checkbox" name="pgids" th:value="${page.id}"/>
                    </td>
                    <td class="col-sm-4 center" th:utext="${page.name}"></td>
                    <td class="col-sm-6 center" th:utext="${page.url}"></td>
                </tr>
            </th:block>
            </tbody>
        </table>
        <button type="submit" class="button nomargin rightmargin-sm button-reef-blue">Create
        </button>
    </div>
    <div class="col-sm-12">
        <label th:utext="${successMessage}" class="successmsg"></label>
    </div>
</div>

角色名称
页码目录
阿西恩
名称
统一资源定位地址
创造

更新

正如下面提到的，我的错误是在变量页面进入bindingResult.hasErrors（）后没有添加变量页面。因此，“如果”如下所示：

if (bindingResult.hasErrors()){
            List<Page> pages = pageService.getAllPages();
            modelAndView.addObject("pages", pages);
            modelAndView.setViewName("admin/role");
    }

if（bindingResult.hasErrors（））{
List pages=pageService.getAllPages（）；
添加对象（“页面”，页面）；
modelAndView.setViewName（“管理员/角色”）；
}

当您提交包含无效数据的表单时

bindingResult.hasErrors() 

将返回true，并且由于if/else子句的原因，您没有输入添加页面的代码部分

所以变量

页数

不包含任何数据，并且您的

th:each

循环将不起任何作用

---

如果您想打印页面，即使输入了无效数据，您也可以在

bindingResult.hasErrors（）

为真时删除

else
，您没有设置模型对象
pages
，那么为什么您会对
${pages}感到惊讶呢
为空且
th:each
无需迭代？无关：你为什么使用
而不是将
th:each
放在
本身上？@Andreas这就是我寻求帮助的原因，这是一个我没有考虑的细节。对你来说，这太明显了，我感谢你的帮助，但也不是要贬低我的问题，或者是吗？你说得很对，我完全忘记了那部分。非常感谢。