Question

我尝试用不同类型的对象构建表单。

像String或Integer这样的简单对象，使用HTML中的thymeleaf“选择”标签都不会出现问题，但是当我想获取一些更复杂的对象时，在请求后总是得到null对象。

这是我的代码：

表格：

import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

public class PersonForm {

    @NotNull
    @Size(min=2, max=30)
    private String name;

    @NotNull
    @Min(18)
    private Integer age;

    private String type;

    @NotNull
    private Address address;

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String toString() {
        return "Person(Name: " + this.name + ", Age: " + this.age + ")";
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }
}

地址：

public class Address {
    String city;
    Integer code;

    public Address(String city, Integer code) {
        this.city = city;
        this.code = code;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

}

Controller:

import javax.validation.Valid;
import java.util.ArrayList;
import java.util.List;

@Controller
public class PersonController implements WebMvcConfigurer {


    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/results").setViewName("results");
    }

    @GetMapping("/")
    public String showForm(PersonForm personForm, Model model) {
        List<String> types = new ArrayList<>();
        types.add("Male");
        types.add("Female");
        types.add("Alian");
        types.add("Non Human");

        List<Address> addresses = new ArrayList<>();
        addresses.add(new Address("Kyiv",01000));
        addresses.add(new Address("Hayvoron",26300));

        model.addAttribute("cities",addresses);
        model.addAttribute("allTypes",types);
        return "form";
    }

    @PostMapping("/")
    public String checkPersonInfo(@Valid PersonForm personForm, BindingResult bindingResult) {


        PersonForm person = personForm;
        if (bindingResult.hasErrors()) {
            return "form";
        }

        return "redirect:/results";
    }
}

一个简单的HTML文件，带有两个下拉列表，带有“字符串类型”参数的列表效果很好，但是参数“地址地址”却无法正常工作。

<html xmlns:th="http://www.thymeleaf.org">

<body>
<!--/*@thymesVar id="personForm" type="com.yurets_y.weblibrary.entity.PersonForm"*/-->
<form action="#" th:action="@{/}" th:object="${personForm}" method="post">
    <table>
        <tr>
            <td>Name:</td>
            <td><input type="text" th:field="*{name}" /></td>
            <td th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Name Error</td>
        </tr>
        <tr>
            <td>Age:</td>
            <td><input type="text" th:field="*{age}" /></td>
            <td th:if="${#fields.hasErrors('age')}" th:errors="*{age}">Age Error</td>
        </tr>
        <tr>
            <td>
                Gender
            </td>
            <td>
                <select th:field="*{type}">
                    <option th:each="type : ${allTypes}"
                            th:value="${type}"
                            th:text="${type}">Wireframe</option>
                </select>
            </td>
        </tr>
        <tr>
            <td>
                Address
            </td>
            <td>
            <select  th:field="*{address}">
                <option th:each="city : ${cities}"
                        th:value="city"
                        th:text="${city.city}"

                >Address</option>
            </select>


        </td>
        <!--</tr>-->
        <tr>
            <td><button type="submit">Submit</button></td>
        </tr>
    </table>
</form>
</body>
</html>

有什么方法可以选择“选择”形式的复杂对象？

Answer 1

这是不可能的，因为Thymeleaf将调用.toString（）方法来设置值。

您可以检查元素。

See the image

因此，最好的策略是为Controller返回元素的ID。

<select th:field="*{addressId}">
    <option th:each="city : ${cities}"
        th:value="${city.code}"
        th:text="${city.city}">
            Address
    </option>
</select>

如何从Thymeleaf表单中选择对象？

1 个答案: