The Criteria.uniqueResult() method make it easier to query a single instance of a persistence object. When no persistence found this method will return a null value.
package org.kodejava.hibernate;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Restrictions;
import org.kodejava.hibernate.model.Genre;
public class UniqueResultExample {
public static Session getSession() throws HibernateException {
String cfg = "hibernate.cfg.xml";
SessionFactory sessionFactory = new Configuration().configure(cfg)
.buildSessionFactory();
return sessionFactory.openSession();
}
public static void main(String[] args) {
try (Session session = getSession()) {
Criteria criteria = session.createCriteria(Genre.class)
.add(Restrictions.eq("id", 1L));
// Convenience method to return a single instance that matches
// the query, or null if the query returns no results.
Object result = criteria.uniqueResult();
if (result != null) {
Genre genre = (Genre) result;
System.out.println("Genre = " + genre.getName());
}
}
}
}
Maven Dependencies
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.6.9.Final</version>
</dependency>
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
<version>8.0.33</version>
</dependency>
</dependencies>
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A programmer, runner and recreational diver, lives on the island of Bali, Indonesia. Programming in Java, Spring Framework, Hibernate / JPA, MySQL. To support me working on this project, buy me a cup of coffee, every little bit helps. Thank you.
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Well, what about NPE? Anyway, thanks for the post.
Hi Igor, Thanks for the correction. A null check has been added to the code snippet.
Does
list()method in criteria returnnull? My understanding is it returns an empty list notnull. Check the following link.Hi Balaji, the example above is about
Criteria.uniqueResult()method, not thelist()method. And the JavaDoc of theuniqueResult()method says it return a single instance that matches the query ornullif the query returns no result.Hello there, I’m using last version of Hibernate, and it tells me that “The method
createCriteria(Class)from the typeSharedSessionContractis deprecate”. What can I do? Thanks a lot dude.Hi Mosab, the
createCriteria(Class persistence)method of theSharedSessionContractand othercreateCriteria(...)methods was deprecated since Hibernate 5.2 and we are suggested to use the JPA Criteria API instead.Thanks for information, I have another question how to get max id in table with hibernate 5 because criteria hiberbate it deprecated.
Thanks.
Be aware that uniqueResult() throws an exception if the resultset contains multiple rows so this isn’t a catch-all for getting a single result.
From the documentation (https://docs.jboss.org/hibernate/orm/current/javadocs/org/hibernate/Criteria.html#uniqueResult–)
Throws: HibernateException – if there is more than one matching result