java当post请求在postman中完成时，它会将所有值传递为NULL

Question

This is my back end where the method is taking a student object and a String Id.

@PostMapping(path="/edit/student")
@RequestMapping(value = "/edit/student", method = RequestMethod.POST)
public void editStudent(@RequestBody Student student,String id){
    ss.editStudent(student,id);
}

When I try to do a post request using postman it sends null for everything.

{
"student":{
    "firstname": "jay",
    "lastname": "patel",
    "studentId": "2",
    "email": "temp163@gmail.com"
},
"id":"1"}

Check this out. this may help a little to understand. Backend gets everything as null.

This is the post-call from the postman. Postman call

Answer 1

它看起来像是作为POST有效负载发送的JSON，而不是学生对象的表示形式。相反，它是一个包含两个成员的对象的表示，一个名为student的学生对象和一个名为id的字符串

{
  "student":{ //<  This is a Student object
    "firstname": "jay",
    "lastname": "patel",
    "studentId": "2",
    "email": "temp163@gmail.com"
  },
  "id":"1" //<  This is a String
} 

如果将该有效负载反序列化为Java类，它将如下所示：

public class SomeObject {
    public Student student;
    public String id;
}

简而言之，您的REST端点需要一个Student对象，但这不是您提供给它的，它无法将这个“SomeObject”表示反序列化为Student的实例

尝试将有效负载更改为端点期望的学生对象的表示形式：

{
  "firstname": "jay",
  "lastname": "patel",
  "studentId": "2",
  "email": "temp163@gmail.com"
}