Java Persistence API

Querying for Objects

Use Query.getResultList() to obtain a list of query results

Query.getResultList() Example

Use Query.getSingleResult() to obtain a single query result

Query.getSingleResult() Example

Use Query.setFirstResult() and Query.setMaxResults() to implement "paging"

Paging Example

  public Employee getEmployees( int start, int max  ) {
    Query query = entityManager.createQuery("select x from Employee x");
    query.setFirstResult( start );
    query.setMaxResults( max );
    return query.getResultList(); // size() <= max!
  }