尚学堂 HQL 查询 1

package com.bjsxt.hibernate;

import java.util.Date;
import java.util.List;

import org.hibernate.Query;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateQLTest {
private static SessionFactory sf;

@BeforeClass
public static void beforeClass() {
sf = new AnnotationConfiguration().configure().buildSessionFactory();
}
@AfterClass
public static void afterClass() {
sf.close();
}

@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
}

@Test
public void testSave() {
Session session = sf.openSession();
session.beginTransaction();

for(int i=0; i<10; i++) {
Category c = new Category();
c.setName("c" + i);
session.save(c);
}

for(int i=0; i<10; i++) {
Category c = new Category();
c.setId(1);
Topic t = new Topic();
t.setCategory(c);
t.setTitle("t" + i);
t.setCreateDate(new Date());
session.save(t);

}

for(int i=0; i<10; i++) {

Topic t = new Topic();
t.setId(1);
Msg m = new Msg();
m.setCont("m" + i);
m.setTopic(t);
session.save(m);

}




session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_01() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Category");
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_02() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Category c where c.name > 'c5'");
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_03() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Category c order by c.name desc");
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_04() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select distinct c from Category c order by c.name desc");
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_05() {
Session session = sf.openSession();
session.beginTransaction();
/*Query q = session.createQuery("from Category c where c.id > :min and c.id < :max");
//q.setParameter("min", 2);
//q.setParameter("max",;
q.setInteger("min", 2);
q.setInteger("max",;*/

Query q = session.createQuery("from Category c where c.id > :min and c.id < :max")
.setInteger("min", 2)
.setInteger("max",;
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getId() + "-" + c.getName());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_06() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Category c where c.id > ? and c.id < ?");
q.setParameter(0, 2)
.setParameter(1,;
// q.setParameter(1,;
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getId() + "-" + c.getName());
}
session.getTransaction().commit();
session.close();

}
//分页
@Test
public void testHQL_07() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Category c order by c.name desc");
q.setMaxResults(4);
q.setFirstResult(2);
List<Category> categories = (List<Category>)q.list();
for(Category c : categories) {
System.out.println(c.getId() + "-" + c.getName());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_08() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select c.id,  c.name from Category c order by c.name desc");
List<Object[]> categories = (List<Object[]>)q.list();
for(Object[] o : categories) {
System.out.println(o[0] + "-" + o[1]);
}
session.getTransaction().commit();
session.close();

}

//设定fetch type 为lazy后将不会有第二条sql语句
@Test
public void testHQL_09() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.category.id = 1");
List<Topic> topics = (List<Topic>)q.list();
for(Topic t : topics) {
System.out.println(t.getTitle());
//System.out.println(t.getCategory().getName());
}
session.getTransaction().commit();
session.close();

}

//设定fetch type 为lazy后将不会有第二条sql语句
@Test
public void testHQL_10() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.category.id = 1");
List<Topic> topics = (List<Topic>)q.list();
for(Topic t : topics) {
System.out.println(t.getTitle());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_11() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Msg m where m.topic.category.id = 1");

for(Object o : q.list()) {
Msg m = (Msg)o;
System.out.println(m.getCont());
}
session.getTransaction().commit();
session.close();

}
//了解即可
//VO Value Object
//DTO data transfer object
@Test
public void testHQL_12() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select new com.bjsxt.hibernate.MsgInfo(m.id, m.cont, m.topic.title, m.topic.category.name) from Msg");

for(Object o : q.list()) {
MsgInfo m = (MsgInfo)o;
System.out.println(m.getCont());
}
session.getTransaction().commit();
session.close();

}

//动手测试left right join
//为什么不能直接写Category名，而必须写t.category
//因为有可能存在多个成员变量（同一个类），需要指明用哪一个成员变量的连接条件来做连接
@Test
public void testHQL_13() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select t.title, c.name from Topic t join t.category c "); //join Category c
for(Object o : q.list()) {
Object[] m = (Object[])o;
System.out.println(m[0] + "-" + m[1]);
}
session.getTransaction().commit();
session.close();

}

//学习使用uniqueResult
@Test
public void testHQL_14() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Msg m where m = :MsgToSearch "); //不重要
Msg m = new Msg();
m.setId(1);
q.setParameter("MsgToSearch", m);

Msg mResult = (Msg)q.uniqueResult();
System.out.println(mResult.getCont());
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_15() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select count(*) from Msg m");

long count = (Long)q.uniqueResult();
System.out.println(count);
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_16() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select max(m.id), min(m.id), avg(m.id), sum(m.id) from Msg m");

Object[] o = (Object[])q.uniqueResult();
System.out.println(o[0] + "-" + o[1] + "-" + o[2] + "-" + o[3]);
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_17() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Msg m where m.id between 3 and 5");

for(Object o : q.list()) {
Msg m = (Msg)o;
System.out.println(m.getId() + "-" + m.getCont());
}
session.getTransaction().commit();
session.close();

}

@Test
public void testHQL_18() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Msg m where m.id in (3,4, 5)");

for(Object o : q.list()) {
Msg m = (Msg)o;
System.out.println(m.getId() + "-" + m.getCont());
}
session.getTransaction().commit();
session.close();

}

//is null 与 is not null
@Test
public void testHQL_19() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Msg m where m.cont is not null");

for(Object o : q.list()) {
Msg m = (Msg)o;
System.out.println(m.getId() + "-" + m.getCont());
}
session.getTransaction().commit();
session.close();

}

public static void main(String[] args) {
beforeClass();
}
}