private static void query() {
        Session session=HibernateUtils.getSession();
        //得到條件物件
        Criteria criteria=session.createCriteria(Student.class);

        /*//where條件中的拼接： age>25
        criteria.add(Restrictions.ge("age", 25));
        // sex='女'
        criteria.add(Restrictions.eq("sex","女"));*/
 



        //age>=25 and age<=26
        //criteria.add(Restrictions.between("age", 25, 26));

        /*//age>=25 and sex='女'
        LogicalExpression logicalExpression=Restrictions.and(Restrictions.ge("age", 25), Restrictions.eq("sex", "女"));
        criteria.add(logicalExpression);*/

        //age>=25
 
 or sex='女'
        /*LogicalExpression logicalExpression=Restrictions.or(Restrictions.ge("age", 25), Restrictions.eq("sex", "女"));
        criteria.add(logicalExpression);*/


        //not sex='女'
        //criteria.add(Restrictions.not(Restrictions.eq("sex", "女")));


        //sex='女'
        //criteria.add
 
(Restrictions.sqlRestriction("sex=?", "女", StandardBasicTypes.STRING));

        // age between 25 and 26 and sex='女'
        criteria.add(Restrictions.sqlRestriction("age between ? and ? and sex=?", new Object[]{25,26,"女"}, new Type[]{StandardBasicTypes.INTEGER,StandardBasicTypes.INTEGER,StandardBasicTypes.STRING}));


        List<Student> students=criteria.list();
        System.out.println(students);


    }

private static void query() {
        Session session=HibernateUtils.getSession();
        /*//得到條件物件
        Criteria criteria=session.createCriteria(Student.class);

        //指定班級延遲載入
        //criteria.setFetchMode("classes", FetchMode.SELECT);
        criteria.setFetchMode("classes", FetchMode.JOIN);

        List<Student> students=criteria.list();

        HibernateUtils.close(session);

        for(Student stu:students){
            System.out.println(stu);
            System.out.println(stu.getClasses());
            System.out.println("===========");
        }*/


        Criteria criteria=session.createCriteria(Classes.class);
        //FetchMode.SELECT:指定載入方式為延遲載入 
        //FetchMode.JOIN:指定載入方式為立即載入 
        criteria.setFetchMode("students", FetchMode.JOIN);
        List<Classes> classes=criteria.list();

        //驗證延遲載入
        //HibernateUtils.close(session);

        for(Classes c:classes){
            System.out.println(c);
            System.out.println("學生：");
            System.out.println(c.getStudents());
        }


    }

private static void query() {
        Session session=HibernateUtils.getSession();
        Criteria criteria=session.createCriteria(Student.class);
        //指定升序排序
        //criteria.addOrder(Order.asc("age"));
        //指定降序排序
        criteria.addOrder(Order.desc("age"));
        //設定分析效果，發現和Query完全相同
        criteria.setFirstResult(0);
        criteria.setMaxResults(8);
        List<Student> students=criteria.list();
        System.out.println(students);
    }

    private static void query() {
        Session session=HibernateUtils.getSession();
        Criteria criteria=session.createCriteria(Student.class);
        // age in(20,22)
        criteria.add(Restrictions.in("age", new Object[]{20,22}));

        /*//select name 
        //criteria.setProjection(Projections.property("name"));
        criteria.setProjection(Property.forName("name"));
        List<String> names=criteria.list();
        System.out.println(names);*/



        /*ProjectionList projectionList=Projections.projectionList();
        //projectionList.add(Projections.property("name"));
        projectionList.add(Property.forName("name"));
        projectionList.add(Projections.property("age"));

        //對指定的查詢列起別名
        projectionList.add(Property.forName("email"), "郵箱");
        //select name,age,email as '郵箱'.....
        criteria.setProjection(projectionList);
        List<Object[]> list=criteria.list();
        for(Object[] objs:list){
            System.out.println(Arrays.toString(objs));
        }*/


        /*//select count(*)
        //criteria.setProjection(Projections.rowCount());

        //select avg(age) from t_student where age in(20,22)
        //criteria.setProjection(Projections.avg("age"));

        //select count(id) from t_student where age in(20,22)
        //criteria.setProjection(Projections.count("id"));
        Object result=criteria.uniqueResult();
        System.out.println("result="+result);*/


        //select age count(id) from t_student where age in(20,22) group by age 
        //group by age
        criteria.setProjection(Projections.projectionList()
                .add(Projections.groupProperty("age")) //如果指定按某個欄位進行分組，則這個欄位會自動出現在select語句中
                .add(Projections.count("id"))
                );
        List<Object[]> list=criteria.list();

        for(Object[] objs:list){
            System.out.println(Arrays.toString(objs));
        }
    }