Spring Rest with Angular 2 - spring

Question

I am having problems with inserting new rows into database with my Angular 2 application.
The problem occures when i try to insert a new entry in database that has a foreign key to another table in the database. My two models defined in Spring are:
#Entity
public class A{
#Id
#NotNull
#GeneratedValue(strategy = GenerationType.AUTO)
private int id;
#OneToMany(mappedBy = "A")
private List<B> b = new ArrayList<B>();
...
}
#Entity
public class B{
#Id
#NotNull
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#NotNull
#ManyToOne
#JoinColumn(name="aId")
private A a;
...
}
Those two models in backend have their counterparts in the frontend. I added the _links part because Spring Rest api gives links instead of foreign keys:
export class A{
id: number;
b: B[];
_links:{...}
...
}
export class B{
id: number;
a: A;
_links:{...}
...
}
I created these models based on what information i get from api. For example, a get request on localhost:8080/api/b/1 gives:
{
"id" : 1,
"_links" : {
"self" : {
"href" : "http://localhost:4200/api/b/1"
},
"b" : {
"href" : "http://localhost:4200/api/b/1"
},
"a" : {
"href" : "http://localhost:4200/api/b/1/a"
}
}
}
I can easily insert new rows into table A (since it doesn't contain foreign keys) with my angular 2 service method shown bellow:
createA(a: A): Observable<A[]>{
return this.http.post(this.AUrl, a)
.map((res:Response) => res.json())
.catch((error:any) => Observable.throw(error.json().error || 'Server Error'));
}
Similarly, service method for creating a new model B looks like:
createB(b: B): Observable<B[]>{
return this.http.post(this.BUrl, b)
.map((res:Response) => res.json())
.catch((error:any) => Observable.throw(error.json().error || 'Server Error'));
}
My repositories in Spring are defined as:
#RepositoryRestResource(collectionResourceRel="a", path="a", itemResourceRel="a")
public interface ARepository extends JpaRepository<A, Integer>{
}
#RepositoryRestResource(collectionResourceRel="b", path="b", itemResourceRel="b"))
public interface BRepository extends JpaRepository<B, Long>{
}
My repository configuration in Spring is:
#Configuration
public class MyRestConfiguration extends RepositoryRestMvcConfiguration{
#Override
protected void configureRepositoryRestConfiguration(RepositoryRestConfiguration config){
config.setBasePath("/api");
config.exposeIdsFor(A.class);
config.exposeIdsFor(B.class);
}
}
When i try to insert a new row into the table B i get the following error in spring:
javax.validation.ConstraintViolationException: Validation failed for classes [......model.B] during update time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
ConstraintViolationImpl{interpolatedMessage='may not be null', propertyPath=a, rootBeanClass=class ........model.B, messageTemplate='{javax.validation.constraints.NotNull.message}'}
]
I would like to know what exactly is the request payload for http post request supposed to look like, in order for the application to insert a new row of B into the database. Any help is greatly appreciated.
Edit:
I have made a spring rest controler with this mapping:
#PostMapping("/api/b")
#ResponseBody
public String createServis(#RequestBody B b){
}
If I make a http post request with this payload (using curl or by some other means, but thats not the point):
{
id:1,
aId:1
}
or this one:
{
id:1,
a:{id:1}
}
or even this one:
{
id:1,
aId:1,
a:{id:1}
}
The property a of the object b remains null / is not properly initialized.

Answer 1

I got my answer here Spring Rest: Cannot insert rows that have #ManyToOne column
Basicaly you need to post:
{
id: 1
a: "http://localhost:4200/api/a/1"
}
to url localhost:4200/api/b