spring boot从angular2的JSON发布请求中将空属性映射到POJO

Question

After doing a big deal of research on the topic I decided to ask in here. I am getting all null properties to the POJO/Model which is supposed to get values from the JSON I am posting from the Angular 2 Front end. Here is the rest controller method:

@RequestMapping(value = "/employees/update",  method = RequestMethod.POST, consumes = "application/json")
    public String allEmployees( @RequestBody Employee emp){
        return "";
    } 

The following is the POJO/Model/Hibernate Entity:

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(nullable = false, updatable = false)
private Long id;

private String firstname;
private String lastname;
private String department;

public Employee(){}

public Long getId() {
    return id;
}
public void setId(Long id) {
    this.id = id;
}
public String getFirstname() {
    return firstname;
}
public void setFirstname(String firstname) {
    this.firstname = firstname;
}
public String getLastname() {
    return lastname;
}
public void setLastname(String lastname) {
    this.lastname = lastname;
}
public String getDepartment() {
    return department;
}
public void setDepartment(String department) {
    this.department = department;
}

The following is the Angular 2 Service method:

updateEmployee(emp:Employee){
  let url: string = "http://localhost:8080/api/employees/update";
  let headers = new Headers();
  headers.append('Content-Type', 'application/json');
  return  this.http.post(url, {emp}, {headers: headers, withCredentials: true }).map(res => res.json());
}

and the Employee interface of Angular 2:

export interface Employee{
  id: number;
  firstname: string;
  lastname: string;
  department: string;
}

What am I doing wrong? I have searched for similar issues but none I found applies to my case. Thank you!

Answer 1

Try annotating the method with @ResponseBody

Which would become:

@ResponseBody
@RequestMapping(value = "/employees/update",  method = RequestMethod.POST, consumes = "application/json")
    public String allEmployees( @RequestBody Employee emp){
        return "";
    } 

Answer 2

You need to serialize the javascript object before sending it. Try:

this.http.post(url, JSON.stringify(emp), {headers: headers, withCredentials: true }).map(res => res.json());