Convert a List<Object> to List String

Question

Query  w=em.createQuery("SELECT ar.authorId.firstName,
                        count(ar) FROM Article ar
                        WHERE ar.categoryId.categoryText=:
                                                 categoryText GROUP BY ar.authorId"); 
       w.setParameter("categoryText", categoryText); 

       List list1=w.getResultList();  


       System.out.println(list1.toString());

Whats the wrong. i get [[Ljava.lang.Object;@60a19573, [Ljava.lang.Object;@44a085e5]

I want to print the query like "name:"+firtname+"Articles:"+count(ar)

cast to specific type of List and then implement toString() in that particular type — Jigar Joshi
– Jigar Joshi, Commented Dec 30, 2014 at 22:33
First of all it would be nice to give your colleagues a hint what the objects are: hibernate??? — Michal Wilkowski
– Michal Wilkowski, Commented Dec 30, 2014 at 22:33
possible duplicate of how to convert object to string in java — Kick Buttowski
– Kick Buttowski, Commented Dec 30, 2014 at 22:33
By default the toString method get the class names. You should have a method like myList.Cast<String>().ToList(), that is how we do in C#. — Miguel Lattuada
– Miguel Lattuada, Commented Dec 30, 2014 at 22:35

Jigar Joshi · Accepted Answer · 2014-12-30 23:59:18Z

4

Implement toString() in that particular type SomeType

edited Dec 30, 2014 at 23:59

answered Dec 30, 2014 at 22:34

Jigar Joshi

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5 Comments

chrylis -cautiouslyoptimistic- Over a year ago

The generic cast isn't necessary just for nice output; toString() is necessary and sufficient.

Dawood ibn Kareem Over a year ago

You could make it a little clearer that the last line of your answer is the only one that matters. If it were me, I'd just delete the first six lines.

John Ament Over a year ago

What is SomeType here?

Jigar Joshi Over a year ago

the object model type class that you are querying from DB

palios7 Over a year ago

please could you be more specific how to do this.

John Ament · Accepted Answer · 2014-12-30 23:45:43Z

2

What you're getting back in your query is a List<Object[]> which is expected as per the spec. The first element in your array is the string ar.authorId.firstName and the second is a Long representing count(ar)

A String.format should work here for you:

for(Object[] objs : list1) {
    System.out.println(String.format("name %s articles %s",objs[0],objs[1]);
}

answered Dec 30, 2014 at 23:45

John Ament

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1 Comment

John Ament Over a year ago

If you're satisfied with the answer @palios7 please do accept it :-)

Rohith K · Accepted Answer · 2014-12-31 06:56:23Z

0

for(Object objs : list1) { System.out.println(String.valueOf(objs)); }

valueOf is an String method which helps to convert primitive data types to String.

answered Dec 31, 2014 at 6:56

Rohith K

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1 Comment

palios7 Over a year ago

it doesnt work i get the same [Ljava.lang.Object;@60a19573, [Ljava.lang.Object;@44a085e5]

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