对象增删改查与HQL查询

最新推荐文章于 2023-06-30 08:35:20 发布

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package Dao;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import domain.User;
import utils.HibernateUtils;
public class UserDao {
//增加用户
@Test
public void addUser(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
User user = new User();//瞬时对象
user.setName("小王");
user.setSex("女");
user.setAge(33);
user.setHeight(180);
user.setHobby("做饭");
session.save(user);//持久对象
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//查询用户
@Test
public void findUser(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
User user = session.get(User.class, 4);//持久对象
System.out.println(user);
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//修改用户
@Test
public void updateUser(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
User user = session.get(User.class, 4);
user.setAge(25);
user.setHobby("吃饭");
session.update(user);//持久对象
System.out.println(user);
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//删除用户
@Test
public void deleteUser(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
User user = session.get(User.class, 6);
session.delete(user);
System.out.println(user);
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//简单查询
@Test
public void queryUser(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
Query query = session.createQuery("from User");
List<User> users = query.list();
for (User user : users) {
System.out.println(user);
}
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//属性查询
@Test
public void queryUserName(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
Query query = session.createQuery("select u.name from User u");
List<String> names = query.list();
for (String user : names) {
System.out.println(user);
}
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//实例化查询
@Test
public void queryUserExample(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
Query query = session.createQuery("from User where age = 21");
List<User> users = query.list();
for (User user : users) {
System.out.println(user);
}
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//统计查询
@Test
public void queryUserGroup(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
Query query = session.createQuery("select avg(u.age) from User u");
Number avgage = (Number) query.uniqueResult();
System.out.println("平均年龄为："+avgage);
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
//子查询
@Test
public void queryUserIn(){
Session session = null;
Transaction ts = null;
try {
session = HibernateUtils.getSession();
ts = session.beginTransaction();
Query query = session.createQuery("from User u where u.age>(select avg(age) from User)");
User user = null;
List list = query.list();
for (int i =0;i<list.size();i++) {
user = (User) list.get(i);
System.out.println(i+"姓名："+user.getName()+"——年龄："+user.getAge());
}
ts.commit();
} catch (Exception e) {
if(ts != null)
{
ts.rollback();
}
e.printStackTrace();
}
}
}