Problem using session.find

ashish261080 · **Joined:** Mon Mar 14, 2005 9:07 am **Posts:** 27

Hi friends,

I have a very weird problem. I have a class called CDViewer.java which retrieves the details of all the CDs from the database. My problem is that when I do

List cds = session.find("from CD");

nothing happens. If you see the code below I have put

Code:

      System.out.println("11111111111111");
      List cds = session.find("from CD");
      System.out.println("22222222222222");  

in the class CDViewer.java. Although "11111111" appears but "2222222222" donot get displayed and no exception is thrown. That means there is some problem in the line

List cds = session.find("from CD");

but I donot understand what the problem is. If I use any other session command (like List cds = session.createQuery("select * from cd").list();) the same thing happens.

Hibernate version: 2.0

Mapping documents:-CD.hbm.xml
--------------------------------------------------------------------

Code:

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE hibernate-mapping 
    PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
    <class name="com.CD" table="cd">
        <id name="id" type="int" unsaved-value="0">
            <column name="ID" sql-type="int" not-null="true"/>
            <generator class="increment"/>
        </id>
        <property name="title" column="TITLE"/>
        <property name="artist" column="ARTIST"/>
        <property name="purchaseDate" column="PURCHASEDATE"/>
        <property name="cost" column="COST"/>
    </class>
</hibernate-mapping>

--------------------------------------------------------------------

Code between sessionFactory.openSession() and session.close():
---------------------------------------------------------------------------------
Class CDViewer.java

Code:

package com;

import java.io.*;
import javax.servlet.*; 
import javax.servlet.http.*; 
import javax.naming.*;
import java.util.*;

import net.sf.hibernate.*;
import net.sf.hibernate.cfg.*;

public class CDViewer extends HttpServlet { 
  private SessionFactory sessionFactory;

  public void init(ServletConfig config) throws ServletException { 
    super.init(config);
    
    try {
      sessionFactory = new Configuration().configure().addClass(com.CD.class).buildSessionFactory();
    } catch(Exception e) {
      e.printStackTrace();
    }
  }

  private void displayAll(PrintWriter out, Session session) {
    try {
      out.println("<html>");
      out.println("<table border='1'>");
      out.println("<tr><td>Title</td><td>Artist</td><td>cost</td></tr>");

System.out.println("11111111111111");
List cds = session.find("from CD");
System.out.println("22222222222222");

Code:

      Iterator iter = cds.iterator();
      while (iter.hasNext()) {
       CD cd = (CD)iter.next();
        out.println("<tr><td>");
       out.println(cd.getTitle());
        out.println("</td><td>");
      out.println(cd.getArtist());
        out.println("</td><td>");
        out.println(cd.getCost());
      out.println("</td></tr>");
      }        
    } catch(Exception e) {}

    out.println("</table>");    
    out.println("</html>");
  }

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response) 
                        throws IOException, ServletException {

    response.setContentType("text/html"); 
    PrintWriter out = response. getWriter();

        Session session = null;

        try {
          session = sessionFactory.openSession();
          String action = request.getParameter("submit"); 
          if (action.equals("Pull All CDs")) { 
            displayAll(out, session);
          } else {
             out.println("Bad Input");
          }

          session.flush();
          session.close();

        } catch (Exception e) {
           e.printStackTrace();
        } 
  }

  public void doPost(HttpServletRequest request,
                    HttpServletResponse response)
                        throws IOException, ServletException {
    doGet(request, response);
  }
}

---------------------------------------------------------------------------------

Name and version of the database you are using:
---------------------------------------------------------------------------------
Oracle 9i
The table has the following fields-
ID,TITLE,ARTIST,PURCHASEDATE,COST
---------------------------------------------------------------------------------

[c]hibernate.cfg.xml
---------------------------------------------------------------------------------

Code:

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@172.16.4.78:1521:prod</property>
        <property name="connection.username">abc</property>
        <property name="connection.password">abc</property>
        <property name="show_sql">true</property>
         <property name="dialect">net.sf.hibernate.dialect.OracleDialect</property>
        <mapping resource="CD.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

---------------------------------------------------------------------------------

Please help as I have been assigned a task and there is nobody I can ask.

ashish261080 · **Joined:** Mon Mar 14, 2005 9:07 am **Posts:** 27

I Forgot to add that below is my CD.java Model class

Code:

package com;

import java.io.*;
import java.util.*;

  public class CD {
    Integer id;
    String title; 
    String artist;
    Date   purchaseDate; 
    Double cost;

    public CD() {
    }

    public void setId(Integer id) { 
      this.id = id;
    }

    public Integer getId(){ 
      return id;
    }

    public void setTitle(String title) { 
      this.title = title;
    }

    public String getTitle() { 
      return title;
    }

    public void setArtist(String artist) { 
       this.artist = artist;
    }

    public String getArtist() { 
      return artist;
    }

    public void setPurchaseDate(Date purchaseDate) { 
      this.purchaseDate = purchaseDate;
    }

    public Date getPurchaseDate() { 
      return purchaseDate;
    }

    public void setCost(Double cost) { 
      this.cost = cost;
    }

    public Double getCost() { 
      return cost;
    }
  }

mveitas · **Posted:** Wed Mar 23, 2005 2:56 am

1. You posted to the wrong forum. This forum is for Hibernate3.x

2. Try using

Code:

session.find("from com.CD");

3. Is the SQL being displayed in standard out?

4. Try turning on the debug for Hibernate to get a sense of where it is failing.

ashish261080 · **Joined:** Mon Mar 14, 2005 9:07 am **Posts:** 27

I tried using com.CD but that didn't help.

Could you please tell me how can i turn the debug option ON for Hibernate. Also what is the link for Hibernate 2 queries.

drj · **Posted:** Wed Mar 23, 2005 4:47 am

Why are you ignoring the exception? NEVER do this:

Code:

      Iterator iter = cds.iterator();
      while (iter.hasNext()) {
       CD cd = (CD)iter.next();
        out.println("<tr><td>");
       out.println(cd.getTitle());
        out.println("</td><td>");
      out.println(cd.getArtist());
        out.println("</td><td>");
        out.println(cd.getCost());
      out.println("</td></tr>");
      }        
    } catch(Exception e) {} 

You should at the bare minimum be logging the exception.

christian · **Posted:** Wed Mar 23, 2005 4:51 am

All of this looks like one of the typical examples from the "Professional Hibernate" book. It's a good idea if you don't continue reading it... and throw it away.