Problem while Join in hibernate

[vinoth subramaniam]

Hi all i am new to hibernate, and i am trying to join two tables called person and contact.I am getting the error in mapping. Please tell whats the problem.

Person Table SQL

create table person (Personid int Not null, street char (20) not null,
contactid int not null,
constraint primary_table Primary key (personid),
constraint foreign_contact foreign key (contactid) references Contact (ID))

Contact Table SQL

create table CONTACT (ID int Not null, FIRSTNAME varchar(50), LASTNAME varchar(50), EMAIL varchar(50))


person class :

  
public class Person {
 
private int personid;
private String street;
private int contactid;

public int getPersonid() {
return personid;
}
public void setPersonid(int personid) {
this.personid = personid;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public int getContactid() {
return contactid;
}
public void setContactid(int contactid) {
this.contactid = contactid;
}

}
  

Contact Class

  
 
public class Contact 
{
 private String firstName;
  private String lastName;
  private String email;
  private int id;
  
  
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}
  

And here is the mapping file for contact class

  
 
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 
<hibernate-mapping >
  <class name="com.tcs.Nulamda.hibernate.Contact" table="CONTACT">
  
   <id name="id" type="int" column="ID"  >
   <generator class="increment"/>
  </id>
 
  <property name="firstName"  column="FIRSTNAME"/>
    
  <property name="lastName" column="LASTNAME"/>
    
  <property name="email" column="EMAIL"/>
    
    <bag name="person" inverse="true" cascade="all,delete-orphan">
    <key column="contactid"></key>
    <one-to-many class="com.tcs.Nulamda.hibernate.Person"  />
   </bag>
    
 </class>
</hibernate-mapping>
 
  

And the person mapping file for person

  
 
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 
<hibernate-mapping >
  <class name="com.tcs.Nulamda.hibernate.Person" table="person">
  
   <id name="personid" type="int" column="Personid"  >
   <generator class="increment"/>
  </id>
 
  <property name="street"  column="street"/>
    
 
  <property name="contactid" column="contactid"/>
    
 <many-to-one name="Contact" class="com.tcs.Nulamda.hibernate.Contact" column="id"
 update="false" insert="false">
 </many-to-one>
    
 </class>
</hibernate-mapping>
 
  

I am getting the following error

  
HTTP Status 500 - 
 
--------------------------------------------------------------------------------
 
type Exception report
 
message 
 
description The server encountered an internal error () that prevented it from fulfilling this request.
 
exception 
 
javax.servlet.ServletException: Could not find a getter for Contact in class com.tcs.Nulamda.hibernate.Person
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:523)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)
 

root cause 
 
org.hibernate.PropertyNotFoundException: [B]Could not find a getter for Contact in class com.tcs.Nulamda.hibernate.Person[/B]org.hibernate.property.BasicPropertyAccessor.createGetter(BasicPropertyAccessor.java:213)
org.hibernate.property.BasicPropertyAccessor.getGetter(BasicPropertyAccessor.java:207)
org.hibernate.mapping.Property.getGetter(Property.java:240)
org.hibernate.tuple.PojoTuplizer.buildPropertyGetter(PojoTuplizer.java:231)
org.hibernate.tuple.AbstractTuplizer.<init>(AbstractTuplizer.java:73)
org.hibernate.tuple.PojoTuplizer.<init>(PojoTuplizer.java:53)
org.hibernate.tuple.TuplizerLookup.create(TuplizerLookup.java:45)
org.hibernate.tuple.EntityMetamodel.<init>(EntityMetamodel.java:208)
org.hibernate.persister.entity.BasicEntityPersister.<init>(BasicEntityPersister.java:398)
org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:104)
org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:55)
org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:199)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1043)
com.tcs.Nulamda.support.UsingSessionFactory.<init>(UsingSessionFactory.java:19)
com.tcs.Nulamda.support.InsertDataToContact.insertContactdetails(InsertDataToContact.java:13)
com.tcs.Nulamda.action.DataInsertAction.execute(DataInsertAction.java:38)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)
 

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.9 logs.
 
  

Thanks in advance....

[Paul Sturrock]

The error says it all.

You have mapped an association in your Person class between person and Contant:

 <many-to-one name="Contact" class="com.tcs.Nulamda.hibernate.Contact" column="id"
 update="false" insert="false">
 </many-to-one>

so your Java class needs getter/setter methods for this property.

[vinoth subramaniam]

Can you Please explain the answer in detail. Or else can you give me some sample code or example, So that i can understand the concept. Thanks...

[Paul Sturrock]

All properties in your mapping file must exist in your Java class, and all properties must have getter and setter methods so Hibernate can manipulate these values. So if you map a property "foo" which is of the type String, your class must have a getter called getFoo() that returns a String and a setter called setFoo(String) that takes a string as a parameter. Associations are the same, if foo is an association to a class called Foo you'll need the same getter and setter methods that deal with Foo objects.