无法将 [java.lang.String] 类型的值转换为属性所需的类型 [org.springframework.web.multipart.MultipartFile]
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Cannot convert value of type [java.lang.String] to required type [org.springframework.web.multipart.MultipartFile] for property
提问by Md Faisal
I am saving an image file from jsp and renaming it in the controller
我正在从 jsp 保存一个图像文件并在控制器中重命名它
The problem is that same piece of code is working in one part of the controller and not working in another part of the controller
问题是同一段代码在控制器的一部分中工作，而在控制器的另一部分中不起作用
here is the jsp code which is same in both cases:-
这是两种情况下相同的jsp代码：-
<div class="form-group ">
<label for="photo">Photo:</label>
<form:input type="file" class="filestyle" path="studentPhoto"
id="studentPhoto" placeholder="Upload Photo"
required="required" />
</div>
Here is the part of the controller where it is working as expected:-
这是控制器按预期工作的部分：-
@RequestMapping(value = "/student", params = "add", method = RequestMethod.POST)
public String postAddStudent(@ModelAttribute @Valid Student student,
BindingResult result, Model model) throws IOException {
if (result.hasErrors()) {
System.out.println(result.getAllErrors().toString());
model.addAttribute("examination_names", ExaminationName.values());
ArrayList<Role> roles = new ArrayList<Role>();
roles.add(Role.STUDENT);
model.addAttribute("roles", roles);
return "student/add";
} else {
System.out.println("Inside postAddStudent");
System.out.println(student);
student = studentService.save(student);
String PROFILE_UPLOAD_LOCATION = servletContext.getRealPath("/")
+ File.separator + "resources" + File.separator
+ "student_images" + File.separator;
BufferedImage photo = ImageIO.read(new ByteArrayInputStream(student
.getStudentPhoto().getBytes()));
File destination = new File(PROFILE_UPLOAD_LOCATION
+ student.getId() + "_photo" + ".jpg");
ImageIO.write(photo, "jpg", destination);
return "redirect:student?id=" + student.getId();
}
}
Below is the part of controller where it is not working and says error:-
以下是控制器无法工作并显示错误的部分：-
Failed to convert property value of type java.lang.String to required type org.springframework.web.multipart.MultipartFile for property studentPhoto; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [org.springframework.web.multipart.MultipartFile] for property studentPhoto: no matching editors or conversion strategy found
ControllerCode
控制器代码
@RequestMapping(value = "/examForm", params = "edit", method = RequestMethod.POST)
public String postEditExamForm(@ModelAttribute @Valid Student student,
BindingResult result, Model model) throws IOException {
String PROFILE_UPLOAD_LOCATION = servletContext.getRealPath("/")
+ File.separator + "resources" + File.separator
+ "student_images" + File.separator;
if (result.hasErrors()) {
model.addAttribute("flags", Flag.values());
return "examForm/edit";
} else {
Student updatedStudent = studentService.findOne(student.getId());
updatedStudent.setDisqualifiedDescription(student
.getDisqualifiedDescription());
student = studentService.update(updatedStudent);
BufferedImage photo = ImageIO.read(new ByteArrayInputStream(student
.getStudentPhoto().getBytes()));
File destination = new File(PROFILE_UPLOAD_LOCATION
+ student.getId() + "_photo" + ".jpg");
ImageIO.write(photo, "jpg", destination);
return "redirect:examForm?id=" + updatedStudent.getId();
}
}
采纳答案by Sanjay Rawat
You were missing enctype="multipart/form-data"in your <form:form...>tag.
你enctype="multipart/form-data"的<form:form...>标签里不见了。
Since your form doesn't had enctype="multipart/form-data"spring was taking <form:input type="file"..as Stringand throwing error when it cannot convert Stringto MultipartFilefor studentPhotoof type MultipartFilein Studentclass.
由于您的形式不有enctype="multipart/form-data"春天正在采取<form:input type="file"..的String和投掷的错误，当它不能转换String到MultipartFile的studentPhoto类型MultipartFile的Student类。
Here's the complete source code.
这是完整的源代码。
