import java.util.Iterator;
import java.util.List;
import org.hibernate.Session;
import junit.framework.TestCase;
/**
* 简单属性查询
* @author Administrator
*
*/
public class SimplePropertyQueryTest extends TestCase {
/**
* 单一属性查询
*/
public void testQuery1() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
//返回结果集属性列表,元素类型和实体类中相应的属性类型一致
List students = session.createQuery("select name from Student").list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
String name = (String)iter.next();
System.out.println(name);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 多个属性查询
*/
public void testQuery2() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
//查询多个属性,其集合元素是对象数组
//数组元素的类型和对应的属性在实体类中的类型一致
//数组的长度取决与select中属性的个数
List students = session.createQuery("select id, name from Student").list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
Object[] obj = (Object[])iter.next();
System.out.println(obj[0] + "," + obj[1]);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 返回Student实体对象
*/
public void testQuery3() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
//如果认为返回数组不够对象化,可以采用hql动态实例化Student对象
//此时list中为Student对象集合
List students = session.createQuery("select new Student(id, name) from Student").list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
Student student = (Student)iter.next();
System.out.println(student.getId() + "," + student.getName());
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 使用别名
*/
public void testQuery4() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
//可以使用别名
List students = session.createQuery("select s.id, s.name from Student s").list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
Object[] obj = (Object[])iter.next();
System.out.println(obj[0] + "," + obj[1]);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
/**
* 使用别名
*/
public void testQuery5() {
Session session = null;
try {
session = HibernateUtils.getSession();
session.beginTransaction();
//可以使用as命名别名
List students = session.createQuery("select s.id, s.name from Student as s").list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
Object[] obj = (Object[])iter.next();
System.out.println(obj[0] + "," + obj[1]);
}
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
session.getTransaction().rollback();
}finally {
HibernateUtils.closeSession(session);
}
}
}