Thymeleaf复选框未传递值

Question

两个问题。

1. 我有User和Note类。用户可以有许多笔记。如何通过Thymeleaf显示属于用户的每个便笺的id？th:text=“${u.notes.id}”不起作用
2. 我有一个表（见图），其中包含每个具有布尔isUserChecked值的用户的复选框，下面是删除选中用户的按钮。Thymeleaf更正显示isUserChecked值的状态。Delete按钮在手动选中checkbox时不起作用，但在代码中设置isUserChecked值时起作用。所以问题出在这个复选框的Thymeleaf语法上。

截图：

HTML

<div class="container">
<div class="row">
        <div class="col-sm-6">
              <table class="table table-hover">
                <thead>
                  <tr>
                    <th>Id</th>
                    <th>Username</th>
                    <th>First name</th>
                    <th>Last name</th>
                    <th>Password (Hash)</th>
                    <th>Role</th>
                    <th>Notes</th>
                    <th>Select</th>
                  </tr>
                </thead>
                <tbody>
                  <tr th:each="u : ${listOfUsers}">
                    <td th:text="${u.id}"></td>
                    <td th:text="${u.username}"></td>
                    <td th:text="${u.firstName}"></td>
                    <td th:text="${u.lastName}"></td>
                    <td th:text="${#strings.substring(u.password,0,5) +'...'}"></td>
                    <td th:text="${u.role}"></td>
                    <td th:text="${u.notes}"></td>     
                    <td><input type="checkbox" name="mycheckbox" 
                     th:value="*{u.isUserChecked()}" th:checked="${u.isUserChecked()}"  /></td>
                  </tr>
                </tbody>
              </table>

            <form th:action="@{/users}" method="post">
                <button class="buttonLogin" type="submit">Submit</button>
            </form>
        </div>
  </div>

更新1

第二个问题。在我的HTML中使用：

<tr th:each="u, i : ${userWrapper}">
<!-- other rows removed for readability -->
<td><input type="checkbox" th:field="*{listOfUsers[__${i.index}__].userChecked}" /></td>

我需要具有list listousers 属性的UserWrapper类。但如何做到这一点呢？我创建了这样的东西：

@Component
public class UserWrapper {

@Autowired
UserService userService;

List<User> listOfUsers = userService.findAll();

public List<User> getListOfUsers() {
    return listOfUsers;
}

public void setListOfUsers(List<User> listOfUsers) {
    this.listOfUsers = listOfUsers;
}
}

以下是此页面的控制器：

@Controller
public class UserController {

@Autowired
UserService userService;

@Autowired 
UserWrapper userWrapper;

@RequestMapping("/users")
public String home(Model model){
    List<User> listOfUsers = userService.findAll();
    model.addAttribute("listOfUsers", listOfUsers);
    return "users";
}

@RequestMapping(value = "users", method = RequestMethod.POST)
public String deleteUser(User user, Model model){
    userService.deleteCheckedUser(user);

    return "redirect:/users";
}
}

在这之后我有一个错误：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController': Unsatisfied dependency expressed through field 'userWrapper'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userWrapper' defined in file [C:\Users\luk89\Desktop\Java\STS Projects\StickyNotes\target\classes\com\twistezo\models\UserWrapper.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.twistezo.models.UserWrapper]: Constructor threw exception; nested exception is java.lang.NullPointerException

更新2

用户控制器：

@Controller
public class UserController {

@Autowired
UserService userService;

@Autowired
UserWrapper userWrapper;

@RequestMapping("/users")
public String home(Model model){
    List<User> listOfUsers = userService.findAll();
    userWrapper.html" target="_blank">setListOfUsers(listOfUsers);

    for(User u : userWrapper.getListOfUsers()){
        System.out.println("username: " +u.getUsername()+ ", checked?: " +u.isUserChecked());
    }

    model.addAttribute("listOfUsers", listOfUsers);
    model.addAttribute("userWrapper", userWrapper);

    return "users";
}

@RequestMapping(value = "/users", method = RequestMethod.POST)
public String deleteUser(@ModelAttribute UserWrapper userWrapper, Model model){

    for(User u : userWrapper.getListOfUsers()){
        System.out.println("username: " +u.getUsername()+ ", checked?: " +u.isUserChecked());
    }

    userService.deleteCheckedUser(userWrapper);

    return "redirect:/users";
    }
}

@Override
public void deleteCheckedUser(UserWrapper userWrapper) {

    for(User u : userWrapper.getListOfUsers()){
        if(u.isUserChecked() == true){
            this.userDAO.delete(u.getId());
        }
    }
}

username: user1, checked?: false
username: user2, checked?: false
username: user3, checked?: false
username: user4, checked?: false
username: user5, checked?: false
username: asd, checked?: false
username: qwe, checked?: false
username: xcv, checked?: false
username: ghj, checked?: false
username: dfh, checked?: false
username: n, checked?: false
username: ed, checked?: false

username: null, checked?: true
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: false
username: null, checked?: true

list listOfUsers=userservice.findall（）；userwrapper.setListOfUsers（listOfUsers）；

但是有这样的情况：用户名：OK,Checked？：不听鼠标单击复选框（所有值都是false）。

Answer 1

对于清单中的每个便笺的id，您需要添加另一个循环。例如，而不是

<td th:text="${u.notes}"></td>

你需要一些类似。

<td><span th:each="note, i: ${u.notes}" th:text="${(i.index > 0 ? ', ' : '') + note.id}" /></td>

--

null

HTML

<form th:action="@{/users}" th:object="${userWrapper}" method="post">
    <!-- other html removed for readability -->
    <tr th:each="u, i : ${listOfUsers}">
        <!-- other rows removed for readability -->
        <td><input type="checkbox" th:field="*{users[__${i.index}__].userChecked}" /></td>
    </tr>
</form>

控制器

@Controller
public class UserController {

    @Autowired UserService userService;

    @RequestMapping("/users")
    public String home(Model model){
        List<User> listOfUsers = userService.findAll();
        UserWrapper userWrapper = new UserWrapper();
        userWrapper.setListOfUsers(listOfUsers);
        model.addAttribute("listOfUsers", listOfUsers);
        model.addAttribute("userWrapper", userWrapper);
        return "users";
    }

    @RequestMapping(value = "users", method = RequestMethod.POST)
    public String deleteUser(@ModelAttribute UserWrapper userWrapper, Model model){
        userService.deleteCheckedUser(userWrapper.getListOfUsers());
        return "redirect:/users";
    }
}

爪哇

public class UserWrapper {
    List<User> listOfUsers = new ArrayList<>();

    public List<User> getListOfUsers() {
        return listOfUsers;
    }

    public void setListOfUsers(List<User> listOfUsers) {
        this.listOfUsers = listOfUsers;
    }
}