Spring Boot 应用程序抛出奇怪的异常

Question

我正在遵循教程，一切似乎对作者有用，但对我不起作用。 该用例的目的是添加一个新类别（id、名称、图像和布尔值）。
类别实体：

@Entity
@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
public class Category {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private String name;
    private String image;
    private Boolean isActive;
}

这是我的控制器：

@PostMapping("/admin/category/add")
public String saveCategory(@ModelAttribute Category category, @RequestParam("image") MultipartFile file,
        HttpSession session) throws IOException {

    String imageName = file != null ? file.getOriginalFilename() : "default.jpg";
    category.setImage(imageName);

    Boolean existCategory = categoryService.existCategory(category.getName());

    if (existCategory) {
        session.setAttribute("errorMsg", "Category Name already exists");
    } else {

        Category saveCategory = categoryService.save(category);

        if (ObjectUtils.isEmpty(saveCategory)) {
            session.setAttribute("errorMsg", "Not saved ! internal server error");
        } else {

            File saveFile = new ClassPathResource("static/img").getFile();

            Path path = Paths.get(saveFile.getAbsolutePath() + File.separator + "category_img" + File.separator
                    + file.getOriginalFilename());

            // System.out.println(path);
            Files.copy(file.getInputStream(), path, StandardCopyOption.REPLACE_EXISTING);

            session.setAttribute("succMsg", "Saved successfully");
        }
    }

    return "redirect:/admin/category";
}

这里的景色：

<form action="/admin/category/add" method="post" enctype="multipart/form-data">
                                <div class="mb-3">
                                    <label>Enter Category</label> <input type="text" name="name" class="form-control">
                                </div>

                                <div class="mb-3">
                                    <label>Status</label>

                                    <div class="form-check">
                                        <input class="form-check-input" type="radio" checked
                                            value="true" name="isActive" id="flexRadioDefault1">
                                        <label class="form-check-label" for="flexRadioDefault1">
                                            Active </label>
                                    </div>
                                    <div class="form-check">
                                        <input class="form-check-input" type="radio" name="isActive"
                                            value="false" id="flexRadioDefault2"> <label
                                            class="form-check-label" for="flexRadioDefault2">
                                            Inactive </label>
                                    </div>

                                </div>

                                <div class="mb-3">
                                    <label>Upload Image</label> <input type="file" name="image"
                                        class="form-control">
                                </div>
                                <button class="btn btn-primary col-md-12 mt-2">Save</button>
                            </form>

我收到以下异常：

There was an unexpected error (type=Bad Request, status=400).
Validation failed for object='category'. Error count: 1
org.springframework.web.bind.MethodArgumentNotValidException: Validation failed for argument [0] in public java.lang.String com.sap.Shopping.Cart.controller.AdminController.saveCategory(com.sap.Shopping.Cart.model.Category,org.springframework.web.multipart.MultipartFile,jakarta.servlet.http.HttpSession) throws java.io.IOException: [Field error in object 'category' on field 'image': rejected value [org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile@4d93b804]; codes [typeMismatch.category.image,typeMismatch.image,typeMismatch.java.lang.String,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [category.image,image]; arguments []; default message [image]]; default message [Failed to convert property value of type 'org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile' to required type 'java.lang.String' for property 'image'; Cannot convert value of type 'org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile' to required type 'java.lang.String' for property 'image': no matching editors or conversion strategy found]]

正如错误所说，图像存在类型不匹配问题，但我不知道到底要更改什么。

Answer 1

出现此错误是因为您使用了 @RequestParam 注释。该注解只能用于检索请求参数。

您必须使用 @RequestPart 注释从多部分表单中检索数据。

@RequestPart("image") MultipartFile file