teacherdaobean.java

jboss4 + Mysql +ejb3.0 EJB3 简单例子

/**
 * Copyright (c)上海烟草(集团)公司与上海康时信息系统有限公司。
 */
package com.myejb.imp;

import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import com.myejb.TeacherDAO;
import com.myejb.entity.Student;
import com.myejb.entity.Teacher;

/**
 * 
 * @author xywang
 * @since 2009-2-13
 * @version 1.0
 * 
 */
@Stateless
@Remote({TeacherDAO.class})
public class TeacherDAOBean implements TeacherDAO{
    @PersistenceContext protected EntityManager em;
    /* （非 Javadoc）
     * @see com.myejb.TeacherDAO#getStudentByID(java.lang.Integer)
     */
    public Student getStudentByID(Integer studentid){
        Student student = em.find(Student.class,studentid);
//        System.out.println("getStudentByID....");
        if(student!=null){
            student.getTeachers().size();
//            System.out.println(" 学生数:"+size);
        }
//        System.out.println("END...."+student);
        return student;
    }

    /* （非 Javadoc）
     * @see com.myejb.TeacherDAO#getTeacherByID(java.lang.Integer)
     */
    public Teacher getTeacherByID(Integer teacherid){
        Teacher teacher = em.find(Teacher.class,teacherid);
        if(teacher!=null){
            teacher.getStudents().size();
        }
        return teacher;
    }

    /* （非 Javadoc）
     * @see com.myejb.TeacherDAO#insertTeacher(java.lang.String, java.lang.String[])
     */
    public void insertTeacher(String name,String[] studentnames){
        Teacher teacher = new Teacher(name);
        if(studentnames!=null){
            for(String stu:studentnames){
                teacher.addStudent(new Student(stu));
            }
        }
        em.persist(teacher);
    }

}