仅基类的Jersey / Jackson序列化问题

Question

Considering following example:

class P { 
    int p = 0;
    public int getP() { return p; }
    public void setP(int p) { this.p = p; }
}

class C extends P { 
    int c = 0;
    public int getC() { return c; }
    public void setC(int c) { this.c = c; }
}

@GET
@Path("test")
@Produces(MediaType.APPLICATION_JSON)
public P testIt() {
    C c = new C();
    c.setP(2);
    P p = c;
    //p.setC(3) or p.getC() would produce error, expectedly
    return p;
}

I'd like my output to be just the fields from the base class, but I get childs fields as well. The examples' output is:

{ "p":2, "c":0 }

while I'd like it to be just:

{ "p":2 }

Now I've seen posts on SO wanting behavior I have and having the behavior I need and didn't see single issue reported similar to mine. This looks like bug rather than misconfiguration to me.

Any ideas what I might be doing wrong or any suggestions? If someone needs some relevant information, just ask. Thanks in advance!

My jersey version is 2.22.1. My jackson version is 2.5.4.

EDIT:

I've tried using other version of jackson and in both 2.2.3 and 2.7.0 the behavior is the same.

Answer 1

You should use the annotation @JsonIgnore on the field getter you dont want to see in the returned JSON

class C extends P { 
    int c = 0;
    @JsonIgnore
    public int getC() { return c; }
    public void setC(int c) { this.c = c; }
}

Otherwise try to cast your C class into P

P p = (P) c;

Answer 2

So as a temporary workaround I added one more class extending P:

class G extends P {
    public G(P p) {super(p);}
}

and added copy constructor to Parent class P:

public P(P p) {this.p = p.getP();}

and in the code used it in following way:

public G testIt() {
    C c = new C();
    c.setP(2);
    P p = c;
    G g = new G(p);
    return g;
}

And now i have desired output.

If noone finds a better way I'll just accept this one as correct answer soon.