nullpointer exception from getHibernateTemplate().execute()
Hi,
I am trying to insert data into database using hibernate. I did the following steps.
1. I used postgres database. I created the table "Person". I used the following query
2. I used the following hbm.xml mapping fileCode:create table PERSON ( ID numeric NOT NULL, NAME character varying(200), SURNAME character varying(200), BIRTHDATE date, SEX character varying(200), CONSTRAINT PERSON_PKEY PRIMARY KEY (ID) );
3. my hibernate.cfg.xml fileCode:<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- Generated Jul 15, 2011 10:15:12 AM by Hibernate Tools 3.2.1.GA --> <hibernate-mapping> <!-- <class name="gr.persons.entities.Person" dynamic-update="false" dynamic-insert="false" table="PERSON"> <cache usage="read-write"/> <id name="id" access="field"> <column name="ID" sql-type="bigserial" length="8" not-null="true"/> <generator class="native" /> </id> --> <class name="main.Person" table="PERSON"> <id name="id" type="big_decimal"> <column name="ID" precision="22" scale="0" /> <generator class="assigned" /> </id> <property name="name" type="string"> <column name="NAME" length="50" /> </property> <property name="surname" type="string"> <column name="SURNAME" length="50" /> </property> <property name="birthdate" type="date"> <column name="BIRTHDATE" length="7" /> </property> <property name="sex" type="string"> <column name="SEX" length="8" /> </property> </class> </hibernate-mapping>
4. my main classCode:<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- Database connection settings --> <property name="connection.driver_class">org.postgresql.Driver</property> <property name="connection.url">jdbc:postgresql://localhost:5432/cemdb</property> <property name="connection.username">postgres</property> <property name="connection.password">NotAllowed@123</property> <!-- JDBC connection pool (use the built-in) --> <property name="connection.pool_size">1</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property> <!-- Enable Hibernate's automatic session context management --> <property name="current_session_context_class">thread</property> <!-- Disable the second-level cache --> <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">true</property> <!-- Drop and re-create the database schema on startup --> <property name="hbm2ddl.auto">update</property> <!-- Mapping files --> <mapping resource="Person.hbm.xml"/> </session-factory> </hibernate-con
5. entity class. Person.javaCode:package main; import java.math.BigDecimal; import java.sql.Timestamp; public class Main { public static void main(String[] args) { PersonManager personManager = new PersonManagerImpl(); Person p = new Person(BigDecimal.valueOf(7), "weada", "dassda", null, "Male"); personManager.saveNewPerson(p); } }
6. manager class (which calls the method saveorupdate in generichibernatedao.java)Code:package main; // Generated Jul 15, 2011 10:15:10 AM by Hibernate Tools 3.2.1.GA import java.math.BigDecimal; import java.util.Date; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Table; import javax.persistence.Temporal; import javax.persistence.TemporalType; /** * Person generated by hbm2java */ @Entity @Table(name="PERSON" ,schema="YOUR_SCHEMA" ) public class Person implements java.io.Serializable { private BigDecimal id; private String name; private String surname; private Date birthdate; private String sex; public Person() { } public Person(BigDecimal id) { this.id = id; } public Person(BigDecimal id, String name, String surname, Date birthdate, String sex) { this.id = id; this.name = name; this.surname = surname; this.birthdate = birthdate; this.sex = sex; } @Id @Column(name="ID", unique=true, nullable=false, precision=22, scale=0) public BigDecimal getId() { return this.id; } public void setId(BigDecimal id) { this.id = id; } @Column(name="NAME", length=50) public String getName() { return this.name; } public void setName(String name) { this.name = name; } @Column(name="SURNAME", length=50) public String getSurname() { return this.surname; } public void setSurname(String surname) { this.surname = surname; } @Temporal(TemporalType.DATE) @Column(name="BIRTHDATE", length=7) public Date getBirthdate() { return this.birthdate; } public void setBirthdate(Date birthdate) { this.birthdate = birthdate; } @Column(name="SEX", length=8) public String getSex() { return this.sex; } public void setSex(String sex) { this.sex = sex; } }
7. GernericHibernateDao.java (copy pasted a part of file, full file is in the attachment)Code:package main; import java.math.BigDecimal; import java.util.ArrayList; import java.util.List; import javax.persistence.NonUniqueResultException; import org.hibernate.HibernateException; public class PersonManagerImpl implements PersonManager { private PersonDAO personDAO = new PersonDAOImpl(); public void saveNewPerson(Person person) { //public void saveNewPerson(T entity) { try { personDAO.saveOrUpdate(person); } catch (HibernateException ex) { System.out.println("Handle your error here"); } } }
Attached is the package "main" which has all the files.Code:package main; //package semina.generic.dao; import java.io.Serializable; import java.sql.SQLException; import java.util.List; import org.hibernate.Criteria; import org.hibernate.FlushMode; import org.hibernate.HibernateException; import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.Transaction; import org.hibernate.criterion.Criterion; import org.hibernate.criterion.DetachedCriteria; import org.hibernate.criterion.Example; import org.hibernate.criterion.Restrictions; import org.springframework.orm.hibernate3.HibernateCallback; import org.springframework.orm.hibernate3.support.HibernateDaoSupport; /** * */ public class GenericHibernateDao<T, ID extends Serializable> extends HibernateDaoSupport implements GenericDao<T, ID> { private Class<T> persistentClass; public GenericHibernateDao(Class<T> persistentClass) { this.persistentClass = persistentClass; // (Class<T>)((ParameterizedType)getClass().getGenericSuperclass()).getActualTypeArguments()[0]; } public Class<T> getPersistentClass(){ return persistentClass; } public void saveOrUpdate(final T entity) { getHibernateTemplate().executeWithNativeSession( new HibernateCallback() { public Object doInHibernate(Session session) throws HibernateException { Transaction tx = session.beginTransaction(); tx.begin(); session.save(entity); tx.commit(); session.close(); return null; } } ); /*getHibernateTemplate().execute(new HibernateCallback(){ public Object doInHibernate(Session session) throws HibernateException, SQLException { session.saveOrUpdate(entity); return null; } });*/ } public void update(final T entity) { getHibernateTemplate().execute(new HibernateCallback(){ public Object doInHibernate(Session session) throws HibernateException, SQLException { session = getSessionFactory().getCurrentSession(); session.update(entity); return null; } }); } }
when i try to run the main.java, the control goes to saveorupdate() in generichibernatedao.java to store the values of the persistent object into the database. but i am getting a nullpointer exception when i try to do so.
Please help
Reply With Quote
