Thymeleaf注册页面-执行处理器'org.thymeleaf.spring4.processor.attr.SpringInputGeneralFieldAttrProcessor'时出错 [英] Thymeleaf registration page - Error during execution of processor 'org.thymeleaf.spring4.processor.attr.SpringInputGeneralFieldAttrProcessor'

问题描述

我正在为网站注册页面.我了解要创建一个新用户，需要一个id，因此我们有以下字段:

I'm making a registration page for a website. I understand that in order for a new User to be created, an id is required, so we have the field:

<input type="hidden" th:field="{*id} />

但是，当我转到页面时，我得到了我在帖子标题中提到的错误.

However, when I go to the page, I get the error I mentioned in this post's title.

这是有问题的表格:

<form th:action="@{/users/register}" th:object="${user}" class="form-signin" method="POST">
    <h2 class="form-signin-heading">Register</h2>
    <input type="hidden" th:field="*{id}" />
    <label for="inputUsername" class="sr-only">Username*</label>
    <input type="text" th:field="*{username}" name="username" id="inputUsername" class="form-control" placeholder="Username" required="required" autofocus="autofocus" />
    <label for="inputEmail" class="sr-only">Email Address*</label>
    <input type="text" th:field="*{email}" name="email" id="inputEmail" class="form-control" placeholder="Email address" required="required" autofocus="autofocus" />
    <label for="inputPassword" class="sr-only">Password</label>
    <input type="password" th:field="*{password}" name="password" id="inputPassword" class="form-control" placeholder="Password" required="required" />
    <label for="inputConfirmPassword" class="sr-only">Confirm Password</label>
    <input type="password" th:field="${confirmPassword}" name="confirmPassword" id="inputConfirmPassword" class="form-control" placeholder="Confirm password" required="required" />
    <button class="btn btn-lg btn-primary btn-block" type="submit">Register</button>
</form>

这是我的UserController:

Here is my UserController:

@RequestMapping("/register")
public String registerAction(Model model) {
    model.addAttribute("user", new User());
    model.addAttribute("confirmPassword", "");
    return "views/users/register";
}

@RequestMapping(value="/register", method = RequestMethod.POST)
public String doRegister(User user) {
    User savedUser = userService.save(user);
    return "redirect:/"; //redirect to homepage
}

以及User实体的第一部分:

And the first part of the User entity:

@Entity
@Table(name = "users")
public class User {

// Default constructor require by JPA
public User() {}

@Column(name = "id")
@Id @GeneratedValue
private Long id;

public void setId(long id) {
    this.id = id;
}

public long getId() {
    return id;
}

据我所知，这里没有错，所以我被困住了.

From what I can see, there's nothing wrong here so I'm stuck.

我正在关注以下示例: https://github.com/cfaddict/spring-boot -介绍

I'm following this example: https://github.com/cfaddict/spring-boot-intro

有什么想法吗?

推荐答案

问题是您声明id属性的方式.该字段使用引用类型Long，该引用类型为null.吸气剂使用原始的long.当Spring访问id字段时，它尝试取消装箱一个导致错误的null值.将您的网域类别更改为

The problem is the way you have declared your id property. The field uses a reference type Long which is null. The getter uses a primitive long. When Spring accesses the id field it tries to unbox a null value causing an error. Change your domain class to be

@Entity
@Table(name = "users")
public class User {

    // Default constructor required by JPA
    public User() {}

    @Id
    @Column(name = "id")
    @GeneratedValue
    private Long id;

    public void setId(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }
}

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