Phil 12.21.15

8:00 – 6:00 VTX

  • No MIT video today. Went out and saw Star Wars. Fun! Need to see it again when the crowds thin out in an IMAX theater.
  • Copied some stunt data into the hibernate_test db.
  • Ran the code that set up the session and connected to the (empty) db. No exceptions, so I think it’s working this time…
  • IDE is tracking annotations. The names in the annotation class need to be the same as the table and element names or there is an error IntelliJ Hibernate Setup
  • Ok, reading and writing into the db. Now to clean it up and separate elements;
  • Here’s the current cleaned up version. Still need to create the table more properly.
    package com.philfeldman.mains;
    
    import com.philfeldman.mappings.Employee;
    import org.hibernate.HibernateException;
    import org.hibernate.Query;
    import org.hibernate.Session;
    import org.hibernate.SessionFactory;
    import org.hibernate.cfg.Configuration;
    import org.hibernate.metadata.ClassMetadata;
    import org.hibernate.service.ServiceRegistry;
    import org.hibernate.service.ServiceRegistryBuilder;
    
    import java.util.Map;
    import java.util.Random;
    
    /**
     * Created by philip.feldman on 12/21/2015.
     *
     * A simple test program that will read and write from a table in a database. In MySql, the
     * table is in the form:
             CREATE TABLE employee (
             id int(11) NOT NULL AUTO_INCREMENT,
             name varchar(50) DEFAULT NULL,
             PRIMARY KEY (id)
     ) ;
     */
    public class EmployeeTest {
        private SessionFactory sessionFactory;
        private ServiceRegistry serviceRegistry;
        private Session session;
        private Random rand;
    
        public EmployeeTest()throws ExceptionInInitializerError{
            this.rand = new Random();
            try {
                Configuration config = new Configuration();
                config.configure("hibernate.cfg.xml");
    
                this.serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
                this.sessionFactory = config.buildSessionFactory(serviceRegistry);
                this.session = this.sessionFactory.openSession();
            } catch (Throwable ex) {
                throw new ExceptionInInitializerError(ex);
            }
        }
    
        public void closeSession(){
            this.session.close();
        }
    
        public void printAllEntityNames(){
            System.out.println("querying all the managed entities...");
            final Map metadataMap = this.session.getSessionFactory().getAllClassMetadata();
            System.out.println("There are [" + metadataMap.keySet().size() + "] members in the set");
            for (Object key : metadataMap.keySet()) {
                System.out.println("key = ["+key.toString()+"]");
            }
        }
    
        public void printAllEmployees(){
            String key = Employee.class.getCanonicalName();
            final Map metadataMap = this.session.getSessionFactory().getAllClassMetadata();
            final ClassMetadata classMetadata = (ClassMetadata) metadataMap.get(key);
            final String entityName = classMetadata.getEntityName();
            final Query query = session.createQuery("from " + entityName);
            System.out.println("executing: " + query.getQueryString());
            for (Object o : query.list()) {
                Employee e = (Employee) o;
                System.out.println("  " + e.toString());
            }
        }
    
        public void addRandomEmployee(){
            try {
                session.beginTransaction();
                Employee employee = new Employee();
                employee.setName("rand(" + this.rand.nextInt(100) + ")");
                session.save(employee);
                session.getTransaction().commit();
            }catch (HibernateException e){
                session.getTransaction().rollback();
            }
        }
    
        public static void main(String[] args){
            try {
                //System.out.println("Employee.class.getCanonicalName: "+Employee.class.getCanonicalName());
                /***/
                EmployeeTest et = new EmployeeTest();
                et.printAllEntityNames();
                et.printAllEmployees();
                et.addRandomEmployee();
                et.closeSession();
                 /***/
            }catch (Exception e){
                e.printStackTrace();
            }
    
        }
    }
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