NativeSQL >HQL.> EJBQL(JPQL 1.0) > QBC(Query By Criteria) > QBE(Query By Example)
@Test
public void testHQL_01() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Category");//相当于select c from Category c;
List<Category> categories = 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 = 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 = 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 = 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", 8);
q.setInteger("min", 2);
q.setInteger("max", 8);*/
Query q = session.createQuery("from Category c where c.id > :min and c.id < :max")
.setInteger("min", 2).setInteger("max", 8);
List<Category> categories = 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, 8);
// q.setParameter(1, 8);
List<Category> categories = 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 = 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 = q.list();
for (Object[] o : categories) {//object的类型就是Category属性的类型
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 = 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 = 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
//使用join后，例如 from Topic t join t.category c，则表示返回的是两种对象了，返回的就是List<Ojbect[]>
//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 "); //不需要用on来表明条件，因为对象间已经有关联关系了
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();
}
//is empty and is not empty 针对集合使用
@Test
public void testHQL_20() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.msgs is empty");
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getId() + "-" + t.getTitle());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_21() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.title like '%5'");
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getId() + "-" + t.getTitle());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_22() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.title like '_5'");
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getId() + "-" + t.getTitle());
}
session.getTransaction().commit();
session.close();
}
//不重要
@Test
public void testHQL_23() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select lower(t.title)," + "upper(t.title),"
+ "trim(t.title)," + "concat(t.title, '***'),"
+ "length(t.title)" + " from Topic t ");
for (Object o : q.list()) {
Object[] arr = (Object[]) o;
System.out.println(arr[0] + "-" + arr[1] + "-" + arr[2] + "-" + arr[3] + "-" + arr[4]
+ "-");
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_24() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select abs(t.id)," + "sqrt(t.id)," + "mod(t.id, 2)"
+ " from Topic t ");
for (Object o : q.list()) {
Object[] arr = (Object[]) o;
System.out.println(arr[0] + "-" + arr[1] + "-" + arr[2]);
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_25() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session
.createQuery("select current_date, current_time, current_timestamp, t.id from Topic t");
for (Object o : q.list()) {
Object[] arr = (Object[]) o;
System.out.println(arr[0] + " | " + arr[1] + " | " + arr[2] + " | " + arr[3]);
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_26() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.createDate < :date");
q.setParameter("date", new Date());
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getTitle());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_27() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("select t.title, count(*) from Topic t group by t.title");
for (Object o : q.list()) {
Object[] arr = (Object[]) o;
System.out.println(arr[0] + "|" + arr[1]);
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_28() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session
.createQuery("select t.title, count(*) from Topic t group by t.title having count(*) >= 1");
for (Object o : q.list()) {
Object[] arr = (Object[]) o;
System.out.println(arr[0] + "|" + arr[1]);
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_29() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("from Topic t where t.id < (select avg(t.id) from Topic t)");//子查询
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getTitle());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_30() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session
.createQuery("from Topic t where t.id < ALL (select t.id from Topic t where mod(t.id, 2)= 0) ");
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getTitle());
}
session.getTransaction().commit();
session.close();
}
//用in 可以实现exists的功能
//但是exists执行效率高
@Test
public void testHQL_31() {
Session session = sf.openSession();
session.beginTransaction();// t.id not in (1)
Query q = session
.createQuery("from Topic t where not exists (select m.id from Msg m where m.topic.id=t.id)");
// Query q = session.createQuery("from Topic t where exists (select m.id from Msg m where m.topic.id=t.id)") ;
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getTitle());
}
session.getTransaction().commit();
session.close();
}
//update and delete
//规范并没有说明是不是要更新persistent object，所以如果要使用，建议在单独的trasaction中执行
@Test
public void testHQL_32() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.createQuery("update Topic t set t.title = upper(t.title)");
q.executeUpdate();
q = session.createQuery("from Topic");
for (Object o : q.list()) {
Topic t = (Topic) o;
System.out.println(t.getTitle());
}
session.createQuery("update Topic t set t.title = lower(t.title)").executeUpdate();
session.getTransaction().commit();
session.close();
}
@Entity
@NamedQueries(
{
@NamedQuery(name="topic.selectCertainTopic", query="from Topic t where t.id = :id")
}
)
/*
@NamedNativeQueries(
{
@NamedNativeQuery(name="topic.select2_5Topic", query="select * from topic limit 2, 5")
}
)
*/
public class Topic {
//不重要
@Test
public void testHQL_33() {
Session session = sf.openSession();
session.beginTransaction();
Query q = session.getNamedQuery("topic.selectCertainTopic");
q.setParameter("id", 5);
Topic t = (Topic) q.uniqueResult();
System.out.println(t.getTitle());
session.getTransaction().commit();
session.close();
}
//Native（了解）
@Test
public void testHQL_34() {
Session session = sf.openSession();
session.beginTransaction();
SQLQuery q = session.createSQLQuery("select * from category limit 2,4").addEntity(
Category.class);
List<Category> categories = q.list();
for (Category c : categories) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testHQL_35() {
//尚未实现JPA命名的NativeSQL
}
@Test
public void testQBC() {
Session session = sf.openSession();
session.beginTransaction();
//criterion 标准/准则/约束
Criteria c = session.createCriteria(Topic.class) //from Topic
.add(Restrictions.gt("id", 2)) //greater than = id > 2
.add(Restrictions.lt("id", 8)) //little than = id < 8
.add(Restrictions.like("title", "t_")).createCriteria("category").add(//又为Topic里面的category属性添加约束
Restrictions.between("id", 3, 5)) //category.id >= 3 and category.id <=5
;
//DetachedCriterea
for (Object o : c.list()) {
Topic t = (Topic) o;
System.out.println(t.getId() + "-" + t.getTitle());
}
session.getTransaction().commit();
session.close();
}
//query by criteria query by example
@Test
public void testQBE() {
Session session = sf.openSession();
session.beginTransaction();
Topic tExample = new Topic();
tExample.setTitle("T_");
Example e = Example.create(tExample).ignoreCase().enableLike();
Criteria c = session.createCriteria(Topic.class).add(Restrictions.gt("id", 2)).add(
Restrictions.lt("id", 8)).add(e);
for (Object o : c.list()) {
Topic t = (Topic) o;
System.out.println(t.getId() + "-" + t.getTitle());
}
session.getTransaction().commit();
session.close();
}