一 HQL查询
1 一次存1个客户，10个联系人。执行三次，存3个客户，30个联系人，为分页查询做准备
@Test
//来3个客户，30个联系人
public void demo1(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Customer customer=new Customer();
customer.setCust_name("小白");
for(int i=0;i<10;i++){
LinkMan linkMan=new LinkMan();
linkMan.setLkm_name("白白"+i);
linkMan.setCustomer(customer);
customer.getSets().add(linkMan);
session.save(linkMan);
}
session.save(customer);
tx.commit();
}
2 HQL的简单查询
@Test
//HQL简单查询,一个简单的查询
public void demo2(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Query query = session.createQuery("from Customer c");//这个Customer是类名
List<Customer> list = query.list();
for (Customer customer : list) {
System.out.println(customer);
}
tx.commit();
}
3 HQL排序查询,降序查询
@Test
//HQL排序查询,降序
public void demo3(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
//升序：asc(默认) 降序：desc
Query query = session.createQuery("from Customer order by cust_id desc");//这个Customer是类名
List<Customer> list = query.list();
for (Customer customer : list) {
System.out.println(customer);
}
tx.commit();
}
4 HQL的条件查询
@Test
//HQL
public void demo4(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
//只有一个条件
/*Query query = session.createQuery("from Customer where cust_name=?");//这个Customer是类名
query.setParameter(0, "小花");*/
//多个条件查询
/*Query query = session.createQuery("from Customer where cust_source=? and cust_name like ?");
query.setParameter(0, "朋友介绍");
query.setParameter(1, "%白");*/
//二 按名称绑定
Query query=session.createQuery("from Customer where cust_source = :a and cust_name like :b");
query.setParameter("a","网络推广");
query.setParameter("b","%紫");
List<Customer> list = query.list();
for (Customer customer : list) {
System.out.println(customer);
}
tx.commit();
}
5 HQL的投影查询
@Test
/**
* 投影查询
*/
public void demo5(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
//投影查询 单个属性
/*List<Object> list =session.createQuery("select c.cust_name from Customer c").list();
for (Object object : list) {
System.out.println(object);
}*/
//这里会包含多种类型，用数组接收,查到两列的值了
/*List<Object[]> list=session.createQuery("select c.cust_name,c.cust_source from Customer c").list();
for (Object[] objects : list) {
System.out.println(Arrays.toString(objects));
}*/
//查询多个属性，封装到对象里面
List<Customer> list=session.createQuery("select new Customer(cust_id,cust_name,cust_source) from Customer").list();
for (Customer customer : list) {
System.out.println(customer);
}
tx.commit();
}
6 HQL的分页查询
@Test
/**
* 分页查询
*/
public void demo6(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Query query = session.createQuery("from LinkMan");
query.setFirstResult(0);
query.setMaxResults(3);//每页显示的条数
List<LinkMan> list = query.list();
for (LinkMan linkMan : list) {
//要在LinkMan实体类中加上toString
System.out.println(linkMan);
}
tx.commit();
}
7 HQL的统计查询
@Test
public void demo8(){
//根据客户来源来统计它的个数
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
//既有String类型又有Long类型，用object类型接收
// List<Object[]> list=session.createQuery("select cust_source,count(*) from Customer group by cust_source").list();
//根据客户来源统计个数大于等于2的
List<Object[]> list=session.createQuery("select cust_source,count(*) from Customer group by cust_source having count(*)>=2").list();
for (Object[] objects:list) {
System.out.println(Arrays.toString(objects));
}
tx.commit();
}
8 HQL的多表查询
@Test
/**
* HQL的多表查询
*/
public void demo9(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
/*List<Object[]> list = session.createQuery("from Customer c inner join c.sets").list();
for (Object[] obj: list
) {
System.out.println(Arrays.toString(obj));
}*/
//迫切内链接
List<Customer> list = session.createQuery("select distinct c from Customer c inner join fetch c.sets").list();
for (Customer customers: list
) {
System.out.println(customers);
}
tx.commit();
}
二 QBC查询
1 QBC的简单查询
@Test
/**
* 简单查询
*/
public void demo1(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Criteria criteria= session.createCriteria(Customer.class);
List<Customer> list = criteria.list();
for(Customer customer:list){
System.out.println(customer);
}
tx.commit();
}
2 QBC的排序查询
@Test
/**
* 排序查询
*/
public void demo2(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Criteria criteria = session.createCriteria(Customer.class);
criteria.addOrder(Order.desc("cust_id"));//asc升序 desc降序
List<Customer> list = criteria.list();
for(Customer customer:list){
System.out.println(customer);
}
tx.commit();
}
3 QBC的分页查询
@Test
/**
* 分页查询
*/
public void demo3(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Criteria criteria = session.createCriteria(LinkMan.class);
criteria.setFirstResult(0);
criteria.setMaxResults(10);
List<LinkMan> list = criteria.list();
for(LinkMan linkMan:list){
System.out.println(linkMan);
}
tx.commit();
}
4 QBC的条件查询
@Test
/**
* 条件查询
*/
public void demo4(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Criteria criteria = session.createCriteria(Customer.class);
/**
* = eq
* > gt
* >= ge
* < lt
* <= le
* <> ne
* like
*/
criteria.add(Restrictions.eq("cust_source","广告"));
criteria.add(Restrictions.like("cust_name","%白"));
List<Customer> list = criteria.list();
for(Customer customer:list){
System.out.println(customer);
}
tx.commit();
}
5 QBC的统计查询
@Test
/**
* 统计查询， 一般还是用HQL的，QBC的不常用
*/
public void demo5(){
Session session=HibernateUtils.getCurrentSession();
Transaction tx=session.beginTransaction();
Criteria criteria = session.createCriteria(Customer.class);
criteria.setProjection(Projections.rowCount());
Long result= (Long)criteria.uniqueResult();
System.out.println(result);
tx.commit();
}
6 QBC的离线条件查询
@Test
/**
* 离线条件查询,在后期的案例中会省很大的时间(相比原来拼接sql语句)
*/
public void demo6(){
DetachedCriteria dc = DetachedCriteria.forClass(Customer.class);
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
Criteria criteria = dc.getExecutableCriteria(session);
List<Customer> list = criteria.list();
for (Customer customer:list
) {
System.out.println(customer);
}
tx.commit();
}
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