JPA多对多示例 hibername

import java.util.ArrayList;import java.util.List;public class groupusertest {public static void main(String[] args) {// TODO Auto-generated method stubEntityManagerHelper.getEntityManager().getTransaction().begin();TGroup tg1=new TGroup("管理员组");List <T_user> lu =new ArrayList<T_user>();T_user tu1=new T_user("用户一");lu.add(tu1);T_user tu2=new T_user("用户一");lu.add(tu2);T_user tu3=new T_user("用户一");lu.add(tu3);tg1.setTusers(lu);TGroupDAO tgDAO=new TGroupDAO();tgDAO.save(tg1);EntityManagerHelper.getEntityManager().getTransaction().commit();}}