Hibernate Java Tutorial

  1. Home
  2. Java Tutorial
  3. Hibernate
  4. Select Specific Fields in a Entity with Criteria and Projections
File: Main.java

import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
  public static void main(String[] args) throws Exception {
    HibernateUtil hibernateUtil = new HibernateUtil();
    hibernateUtil
        .executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
    Session session = hibernateUtil.getSession();
    Survey survey = new Survey();
    survey.setName("Survey");
    survey.setPurchaseDate(new Date());
    session.save(survey);
    
    survey = new Survey();
    survey.setName("Survey1");
    survey.setPurchaseDate(new Date());    
    session.save(survey);
    
    session.flush();
    
    Criteria crit = session.createCriteria(Survey.class);
    ProjectionList projList = Projections.projectionList();
    projList.add(Projections.property("Id"));
    projList.add(Projections.property("name"));
    crit.setProjection(projList);
    
    List results = crit.list();
    System.out.println(results);
    
    session.close();
    hibernateUtil.checkData("select * from survey");
  }
}
File: Survey.java

import java.util.Date;
public class Survey {
  private int id;
  private String name;
  private Date purchaseDate;
  public Date getPurchaseDate() {
    return purchaseDate;
  }
  public void setPurchaseDate(Date purchaseDate) {
    this.purchaseDate = purchaseDate;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
}
File: Survey.hbm.xml


    "-//Hibernate/Hibernate Mapping DTD 2.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

    
        
    
       
      
            
        
         
    
File: HibernateUtil.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
  Session session;
  Statement st;
  public HibernateUtil() throws Exception{
    SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
    session = sessionFactory.openSession();
    // Load the JDBC driver.
    Class.forName("org.hsqldb.jdbcDriver");
    System.out.println("Driver Loaded.");
    // Establish the connection to the database.
    String url = "jdbc:hsqldb:data/tutorial";
    Connection conn = DriverManager.getConnection(url, "sa", "");
    System.out.println("Got Connection.");
    st = conn.createStatement();
  }
  public Session getSession(){
    return session;
  }
  public void executeSQLCommand(String sql) throws Exception {
    st.executeUpdate(sql);
  }
  public void checkData(String sql) throws Exception {
    ResultSet rs = st.executeQuery(sql);
    ResultSetMetaData metadata = rs.getMetaData();
    for (int i = 0; i < metadata.getColumnCount(); i++) {
      System.out.print("\t"+ metadata.getColumnLabel(i + 1)); 
    }
    System.out.println("\n----------------------------------");
    while (rs.next()) {
      for (int i = 0; i < metadata.getColumnCount(); i++) {
        Object value = rs.getObject(i + 1);
        if (value == null) {
          System.out.print("\t       ");
        } else {
          System.out.print("\t"+value.toString().trim());
        }
      }
      System.out.println("");
    }
  }
}
File: hibernate.cfg.xml


    "-//Hibernate/Hibernate Configuration DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

    
        
        org.hsqldb.jdbcDriver
        jdbc:hsqldb:data/tutorial
        sa
        
        
        1
        
        org.hibernate.dialect.HSQLDialect
        
        org.hibernate.context.ManagedSessionContext
        false
        false
        
        
        org.hibernate.cache.NoCacheProvider        
        
        true