spring api - jackson将一个对象序列化为一个数组

Question

I'm encountering a problem about the way jackson serialize an object.

I have a class

public List<Solution> getSolutionForSearching() {
   String hql = "SELECT id,description  FROM Solution";         
     Session session = solutionDao.getSession();        
     Query query =session.createQuery(hql);         
     return query.list();   
}

I only wanted to select id and description from database:

 [ { id: 35, description: "12" }, { id: 36, description: "1a"   }]

And I expected the response is an array of objects

[ [35, "12" ], [  36, "1a"  ]]

but the obtained result is an array of arrays

 [ [35, "12" ], [ 36, "1a" ]] 

How to serialize the response data to match the requirements?

Answer 1

You hql query does not return instances of type Solution . Instead it returns int, String pairs. So the Jackson cannot map them to the correct form.

You should either return complete objects Solution from the database, or you map the results of the query to Solution object before you pass it to Jackson.

Currently your Solution object is very small, so you don't have to worry about the performance. Just modify the hql query like this:

String hql = "SELECT solution FROM Solution solution";