javax. persistence. NoResultException

[Sam Venkata]

Hi,
I am new to JPA and I have this issue...
I need to get an entity from the database based on the phone number and if the phone number exists my code works fine but throws javax.persistence.NoResultException: No entity found for query if the number does not. All I want ot do is to return null if the phone number does not exist in the database. Can any body help me with this..

my code is as follows..

 
public User findByMdn(final String mdn) throws AuthenticationException {
 
        EntityManager mgr = getEntityManager();
        Query devicesQuery = mgr.createNamedQuery("dvrUserByMdn");
        devicesQuery.setParameter("phno", phno);
        DVRUser result = null;
        try {
           try{
            if(devicesQuery.getSingleResult()!= null){
 
                result = (User) devicesQuery.getSingleResult();
            }
           }catch(javax.persistence.NoResultException nre){
               
           }
        } catch (EntityNotFoundException enfe) {
            System.out.println("enfe caught");
            result = null;
            throw new AuthenticationException("No User found with the phno : "
                + mdn);
        }
        System.out.println("no exception caught");
        return result;
    }
 

Can some body help me with this...

Thanks,
Samanth.

[Jaikiran Pai]

Originally posted by Samanth Marisetty:
try{
if(devicesQuery.getSingleResult()!= null){

result = (User) devicesQuery.getSingleResult();
}
}catch(javax.persistence.NoResultException nre){

}

As per the Javadocs of this API:

Execute a SELECT query that returns a single result.

Returns:
the result
Throws:
NoResultException - if there is no result
NonUniqueResultException - if more than one result
IllegalStateException - if called for a Java Persistence query language UPDATE or DELETE statement

So why dont you try the other getResultList() API by setting the maxResults to 1 as follows:

devicesQuery.setMaxResults(1);
           List resultList = devicesQuery.getResultList();
           if (resultList != null && !resultList.isEmpty()) {
           User user = (User) resultList.get(0);
           
           }