Java Spring 4 - HTTP 状态 400，所需参数不存在
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Spring 4 - HTTP Status 400, Required parameter is not present
提问by Radek Anuszewski
I have Spring form in index.jsp:
我在index.jsp 中有 Spring 表单：
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<body>
<form:form action="save" name="employeeDTO" method="POST">
<label for="name">Name</label><input id="name" type="text" required><br>
<label for="surname">Surname</label><input id="surname" type="text" required><br>
<label for="email">E-mail</label><input id="email" type="email" required><br>
<label for="salary">Salary</label><input id="salary" type="number" required><br>
<input type="submit" value="Save">
</form:form>
</body>
</html>
In WorkController.javaI try to map form submit (at this moment, it doesn't do anything with data):
在WorkController.java 中，我尝试映射表单提交（此时，它不会对数据执行任何操作）：
@Controller
public class WorkController {
@RequestMapping(value = "/save", method = RequestMethod.POST)
public String save(@RequestParam EmployeeDTO employeeDTO){
return "saved";
}
}
But I got HTTP 400 Status: Required EmployeeDTO parameter 'employeeDTO' is not presentwith description: The request sent by the client was syntactically incorrect.
但我得到了 HTTP 400 状态：Required EmployeeDTO parameter 'employeeDTO' is not present带有描述：The request sent by the client was syntactically incorrect.
There is EmployeeDTO.java:
有EmployeeDTO.java：
public class EmployeeDTO implements Serializable, DTO {
private Long id;
private String name;
private String surname;
private String email;
private Double salary;
public EmployeeDTO(){}
public EmployeeDTO(Long id, String name, String surname, String email, Double salary){
this.id = id;
this.name = name;
this.surname = surname;
this.email = email;
this.salary = salary;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return surname;
}
public void setSurname(String surname) {
this.surname = surname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Double getSalary() {
return salary;
}
public void setSalary(Double salary) {
this.salary = salary;
}
@Override
public Serializable toEntity() {
return new Employee(getId(), getName(), getSurname(), getEmail(), getSalary());
}
}
If I remove @RequestParam EmployeeDTO employeeDTOfrom savemethod signature - it works, it redirects to saved.jspfile. Earlier, I uses @RequestParam String name, @RequestParam String surname etcto catch data from HTML forms. Is there any solution to "catch" data from Spring form as DTO object? I wolud be happy if anbyody decides to help me - thank you in advance.
如果我@RequestParam EmployeeDTO employeeDTO从save方法签名中删除- 它有效，它会重定向到saved.jsp文件。早些时候，我使用@RequestParam String name, @RequestParam String surname etc从 HTML 表单中捕获数据。是否有任何解决方案可以从 Spring 表单中“捕获”数据作为 DTO 对象？如果 anbyody 决定帮助我，我会很高兴 - 在此先感谢您。
采纳答案by sarwar026
You may try with @ModelAttribute(Visit ModelAttribute question in SOto get clear understanding about it)
您可以尝试使用@ModelAttribute（访问SO 中的 ModelAttribute 问题以清楚了解它）
@RequestMapping(value = "/save", method = RequestMethod.POST)
public String save(@ModelAttribute("employeeDTO") EmployeeDTO employeeDTO){
return "saved";
}
I used this in spring mvc 3.1
我用过这个 in spring mvc 3.1
回答by kamoor
Use @RequestBody to map all entire body content (Example: JSON) to your DTO object. Use @ModelAttribute for map all the form post parameters to DTO object.
使用@RequestBody 将所有整个正文内容（例如：JSON）映射到您的 DTO 对象。使用@ModelAttribute 将所有表单发布参数映射到 DTO 对象。
回答by Roberto Fernandez
Use @ModelAttribute to bind your DTO (in Spring form) to a Controller method's parameter.
使用@ModelAttribute 将您的 DTO（以 Spring 形式）绑定到 Controller 方法的参数。
http://docs.spring.io/spring/docs/3.0.x/spring-framework-reference/html/mvc.html#mvc-ann-modelattrib
http://docs.spring.io/spring/docs/3.0.x/spring-framework-reference/html/mvc.html#mvc-ann-modelattrib
Hope this helped.
希望这有帮助。
回答by Master Slave
As mentioned in the previous answers, @ModelAttirubeis a part of your fix, but, to have the values actually bind to the model attribute, you'll have to add the name attributes on your form, like this
正如前面的答案中提到的，@ ModelAttrube是您修复的一部分，但是，要将值实际绑定到模型属性，您必须在表单上添加名称属性，如下所示
<form:form action="save" name="employeeDTO" method="POST">
<label for="name">Name</label><input id="name" name="name" type="text" required><br>
<label for="surname">Surname</label><input id="surname" name="surname" type="text" required><br>
<label for="email">E-mail</label><input id="email" type="email" name="email" required><br>
<label for="salary">Salary</label><input id="salary" type="number" name="salary" required><br>
<input type="submit" value="Save">
</form:form>
回答by Nandita Rasam
If u are using spring MVC then make sure you have "@RequestMapping" for "ModelAndView" in your controller for the JSP. and check your ajax call in jsp page for synatax. and this url may help you
如果您使用的是 spring MVC，请确保您在 JSP 的控制器中为“ModelAndView”设置了“@RequestMapping”。并在jsp页面中检查您的ajax调用是否有synatax。这个网址可能对你有帮助
HTTP Status 400 - Required String parameter 'xx' is not present
