JavaEE Training Note - Day 03

package jackq.mvc.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
// specify a controller 
@Controller
// map this controller to '/' or '/home/'
@RequestMapping({"/", "/home/"})
public class Home {
    // map to '/' or 'home'
    // concated to the controller class level mapping
    @RequestMapping("/")
    public String Index(){
        // return the name of the view
        return "home/index";
    }
}

// Model class for test, this is merely a POJO 
package jackq.mvc.model;
public class HelloMessage {
    private String name;
    private String message;
    public HelloMessage() {
    }
    public HelloMessage(String name, String message) {
        this.name = name;
        this.message = message;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
}

package jackq.mvc.controller;
import jackq.mvc.model.HelloMessage;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
@RequestMapping({"/", "/home/"})
public class Home {
    @RequestMapping("/")
    public String Index(){
        return "home/index";
    }
    @RequestMapping("/hello")
    public String Hello(@ModelAttribute("message") HelloMessage message){
        return "home/hello";
    }
}

// Model class 
package jackq.hibernate;
import org.hibernate.Session;
import java.util.List;
public class HelloDao{
    private Session session;
    public HelloDao(Session session){
        this.session = session;
    }
    void addHelloMessage(Hello hello){
        session.persist(hello);
    }
    List<Hello> listHelloMessage(){
        List<Hello> list =  (List<Hello>) session.createQuery("from Hello").list();
        return list;
    }
    void deleteHelloMessage(Hello hello){
        session.delete(hello);
    }
    void updateHelloMessage(Hello hello){
        session.update(hello);
    }
    Hello findHelloMessageById(int id){
        return session.byId(Hello.class).load(id);
    }
}

// DAO: data access object
package jackq.hibernate;
import org.hibernate.Session;
import java.util.List;
public class HelloDao{
    private Session session;
    public HelloDao(Session session){
        this.session = session;
    }
    void addHelloMessage(Hello hello){
        session.persist(hello);
    }
    List<Hello> listHelloMessage(){
        List<Hello> list =  (List<Hello>) session.createQuery("from Hello").list();
        return list;
    }
    void deleteHelloMessage(Hello hello){
        session.delete(hello);
    }
    void updateHelloMessage(Hello hello){
        session.update(hello);
    }
    Hello findHelloMessageById(int id){
        return session.byId(Hello.class).load(id);
    }
}

// Test class 
package jackq.hibernate;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
public class Main {
    private static final SessionFactory ourSessionFactory;
    static {
        // Create session factory on the startup of the application
        try {
            StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure().build();
            ourSessionFactory = new MetadataSources(registry).buildMetadata().buildSessionFactory();
        } catch (Throwable ex) {
            throw new ExceptionInInitializerError(ex);
        }
    }
    public static Session getSession() throws HibernateException {
        return ourSessionFactory.openSession();
    }
    public static void main(final String[] args) throws Exception {
        final Session session = getSession();
        try {
            HelloDao dao = new HelloDao(session);
            // Create an new transaction
            session.beginTransaction();
            // insert data
            dao.addHelloMessage(new Hello("Jack Q", "Hello"));
            dao.addHelloMessage(new Hello("Jack Q", "Hello 2"));
            dao.addHelloMessage(new Hello("Jack Q", "Hello 3"));
            dao.addHelloMessage(new Hello("Jack Q", "Hello 4"));
            // finish the transaction and commit data 
            session.getTransaction().commit();
            // list data
            dao.listHelloMessage().forEach(System.out::println);
            // find and update object
            session.beginTransaction();
            Hello hello = dao.findHelloMessageById(1);
            hello.setName("Java");
            dao.updateHelloMessage(hello);
            session.getTransaction().commit();
            // find and delete object
            session.beginTransaction();
            dao.deleteHelloMessage(dao.findHelloMessageById(2));
            session.getTransaction().commit();
            // list data again
            dao.listHelloMessage().forEach(System.out::println);
        } finally {
            session.close();
        }
        System.out.println("END");
        // Program will not exit without explicit exit since 
        // Hibernate enable multiple thread feature in this configuration
        System.exit(0);
    }
}