Print whole structure with single call (like JSON.stringify) in Java?

Question

How to print any class instance in Java? Similar to JSON.stringify() in Javascript. Not necessary JSON, any format of output will do.

public class User {
    pub         


        

Answer 1

You have two options here. The simple one is just to override the toString function for your class. I dont see why you dont do this really. In this case its as simple as

String toString(){
    return "{ name:\""+name+", password: \""+passowrd....
}

The second option is to use reflection. This would be slightly (though not really) better if you had some sorta external class used for "printing classes". The pseudo code for that would be

StringBuilder s = new StringBuidler();
for(Field f : fields){
    s.append(f.getName() + "\" :\"" + f.get()+ "\"");
}
return s.toString();

However this would be costly as reflection always is. Also if you just properly override the toString functions in the first place your printClass function could literally just be

String printClass(Object o){ return o.toString();}

Which of course again begs the question of why do you need a printClass function?