Java Jackson : Can I hold in a json the type to deserialize it to? -

the usual way serialize json , is:

string catstr = mapper.writevalueasstring(cat); cat catout = mapper.readvalue(catstr, cat.class); 

is there way add (maybe annotation ) type json on serialization , let mapper take value when deserialize it?

so can following

object obj = mapper.readvalue(catstr); 

and later...

cat catout = (cat)obj;  

thanks.

sort of. can add property serialization indicate class is. , when deserializing it, jackson deduces class automatically.

but cannot deserialize object, need base class/interface objects want behave this. , interface needs use @jsontypeinfo annotation, signalling jackson when deserializing base class use property class distinguish type.

example:

@jsontypeinfo(use = jsontypeinfo.id.class, include = jsontypeinfo.as.property) private abstract class base {  }  private class extends base {     private final int i;      @jsoncreator     public a(@jsonproperty("i") int i) {         this.i = i;     } } 

when serialized be:

{"@class":"com.test.a","i":3}

testing code:

    a = new a(3);     string str = mapper.writevalueasstring(a);     base base = mapper.readvalue(str, base.class);