Hibernate 中的 DetachedCriteria查詢(所有使用到的類屬性必須在映射文件中存在)

DetachedCriteria對象爲hibernate的離線查詢對象(即該對象不是由session創建[由forClass或者forEntityName來創建]，查詢的動態sql語句在web層即可以生成[即可以脫離session來動態構建sql語句，進行查詢])
查找哪一個類：


  DetachedCriteria criteria = DetachedCriteria.forClass(Project.class);


判斷類屬性(表中列，以後直接用列表示)是否等於某個值：


DetachedCriteria.add(Restrictions.eq("user.id", userId));


or查詢條件


        Criterion leader = Restrictions.eq("leader.id", userId);
        Criterion member = Restrictions.eq("members.member.id", userId);
        LogicalExpression orExp1 = Restrictions.or(leader, member);
        criteria.add(orExp1);
like查詢條件


Criterion fullName = Restrictions.like("fullName", findKey);
Criterion shortName = Restrictions.like("shortName", findKey);
Criterion leaderName = Restrictions.like("key", findKey);
LogicalExpression orExp = Restrictions.or( Restrictions.or(fullName, shortName), leaderName);
criteria.add(orExp);


5、查詢數據一共有多少條


DetachedCriteria criteria = this.createFindProjectsCriteria(findKey, userId, scope) ;
criteria.setProjection(Projections.rowCount());
List results = getHibernateTemplate().findByCriteria(criteria);
int count = ((Integer) results.get(0)).intValue();
return count;
查詢不重複的數據條數(其它同5)
 criteria.setProjection(Projections.countDistinct("key"));根據主鍵key來查


動態關聯查詢


     List cats = sess.createCriteria(Cat.class)
    .add( Restrictions.like("name", "Fritz%") )
    .setFetchMode("mate", FetchMode.EAGER)
    .setFetchMode("kittens", FetchMode.EAGER)
.list();

添加按列排序：


criteria.addOrder(Order.asc(類的屬性));


去掉重複項  ：


(1)criteria.setResultTransformer(DetachedCriteria.DISTINCT_ROOT_ENTITY);
(2)detachedCriteria.setProjection(Projections.distinct(Projections.property(str)));


detachedCriteria.setProjection(Projections.groupProperty(str));
使用自定義的sql語言查詢
criteria.add(Restrictions.sqlRestriction("  project_Id="+projectId+" connect by prior id= prev_ver "));
使用自定義的sql返回實體類的集合
criteria.add(Restrictions.sqlRestriction("  project_Id="+projectId+" connect by prior id= prev_ver ")).addxxx();
Query query =session.createSQLQuery(sql).addEntity(Project.class);
query.setString("active", "Y");
query.setLong("leaderId", userId); 
條件拼裝完成後，邊可以進行查詢了 ：
getHibernateTemplate().findByCriteria