public static void main(String[] args) throws Exception {
System.out.println("hello from Customer.java");
EntityManagerFactory factory = Persistence.createEntityManagerFactory("customerPU");
EntityManager manager = factory.createEntityManager();
Query q1 = manager.createQuery("SELECT COUNT(c) FROM Customer c");
Long count = (Long) q1.getSingleResult();
if (count == 0) {
// record is empty, read from data.txst
System.out.println("record empty, read from data.txt...");
// try {
FileReader fr = new FileReader("data.txt");
BufferedReader br = new BufferedReader(fr);
String s;
while ((s = br.readLine()) != null) {
// System.out.println(s);
// split the string s
Object[] items = s.split("\\|");
// store in string list
// List<String> itemList= new ArrayList<String>(Arrays.asList(items));
// string list converted to array
// Object[] itemArray = itemList.toArray();
// insert data into database table
manager.getTransaction().begin();
Customer c = new Customer();
// add email
c.setEmail((String) items[0]);
// add pass
c.setPass((String) items[1]);
// add name
c.setName((String) items[2]);
// add address
c.setAddress((String) items[3]);
// add yob
c.setYob((String) items[4]);
// change to managed state
manager.persist(c);
manager.getTransaction().commit();
}
fr.close();
}
// display the records
Query q2 = manager.createNamedQuery("Customer.findAll");
List<Customer> customers = q2.getResultList();
for (Customer c : customers) {
System.out.println(c.getName() + ", " + c.getEmail());
}
manager.close();
factory.close();
}
