Hi
I have developed a servlet. This servlet is inserting record into postgres sql through hibernate using eclispe ide. When I run my code then I find the following exception
exception
java.lang.NullPointerException
hibernate.example.FirstExample.doGet(FirstExample.java:54)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
I have developed the following code
package hibernate.example;
public class Contact {
private String firstName;
private String lastName;
private String email;
private long id;
public String getEmail() {
return email;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
public void setEmail(String string) {
email = string;
}
public void setFirstName(String string) {
firstName = string;
}
public void setLastName(String string) {
lastName = string;
}
public long getId() {
return id;
}
public void setId(long l) {
id = l;
}
}
**Now the servlet is**
package hibernate.example;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class FirstExample extends HttpServlet {
Session session = null;
public String getServletInfo() {
return "Servlet connects to PostgreSQL database and displays result of a SELECT";
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
try{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
Configuration cfg = new Configuration().configure();
SessionFactory factory = cfg.buildSessionFactory();
session = factory.openSession();
out.println("Inserting Record");
Contact contact = new Contact();
contact.setId(6);
contact.setFirstName("Deepak");
contact.setLastName("Kumar");
contact.setEmail("deepak_38@yahoo.com");
session.save(contact);
out.println("Done");
}
catch(Exception e){
System.err.println(e.getMessage());
}
finally{
session.flush();
session.close();
}
}
}
**web.xml is**
<web-app>
<database>
<driver>
<type>org.postgresql.Driver</type>
<url>jdbc:postgresql://127.0.0.1:5432/ali</url>
<user>ali</user>
<password>ali</password>
</driver>
</database>
<servlet>
<servlet-name>FirstExample</servlet-name>
<servlet-class>hibernate.example.FirstExample</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>FirstExample</servlet-name>
<url-pattern>/hb</url-pattern>
</servlet-mapping>
</web-app>
**And contact.hbm.xml is**
<?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="hibernate.example.Contact" table="CONTACT">
<id name="id" type="long" column="ID" >
<generator class="assigned"/>
</id>
<property name="firstName">
<column name="FIRSTNAME" />
</property>
<property name="lastName">
<column name="LASTNAME"/>
</property>
<property name="email">
<column name="EMAIL"/>
</property>
</class>
</hibernate-mapping>
**And hibernate.cfg.xml is**
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.postgressql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:postgresql://127.0.0.1:5432/ali</property>
<property name="hibernate.connection.username">ali</property>
<property name="hibernate.connection.password">ali</property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<!-- Mapping files -->
<mapping resource="contact.hbm.xml"/>
</session-factory>
</hibernate-configuration>
Pleas tell me that where I have done the mistake and how can I resolove the error.