Hibernate QBC学习举例
public void testQBC() { // 方法 说明 // Restrictions.eq ＝ // Restrictions.allEq 利用Map来进行多个等于的限制 // Restrictions.gt ＞ // Restrictions.ge ＞＝ // Restrictions.lt ＜ // Restrictions.le ＜＝ // Restrictions.between BETWEEN // Restrictions.like LIKE // Restrictions.in in // Restrictions.and and // Restrictions.or or // Restrictions.sqlRestriction 用SQL限定查询 //介绍以下几个典型的用法，这样其他的也会用了 /* * 简单的加些限制条件进行搜索 * Restrictions.eq */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); Criterion criterion1 = Restrictions.eq("addr", "dalian"); Criterion criterion2 = Restrictions.eq("name", "tie"); criteria.add(criterion1); criteria.add(criterion2); List users = criteria.list(); for(User user : users){ System.out.println(user.introduce()); System.out.println("**********************"); }*/ /* * Restrictions.allEq 利用Map来进行多个等于的限制 */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); Map para = new HashMap(); para.put("addr", "dalian"); para.put("name", "tie"); Criterion criterion1 = Restrictions.allEq(para); criteria.add(criterion1); List users = criteria.list(); for(User user : users){ System.out.println(user.introduce()); System.out.println("**********************"); }*/ /* * Restrictions.sqlRestriction用SQL限定查询 * Restrictions.sqlRestriction()这里有三个重载的方法， */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); //1. Criterion criterion1 = Restrictions.sqlRestriction("{alias}.name='tie' and {alias}.addr='dalian'"); //2. Criterion criterion1 = Restrictions.sqlRestriction("alias}.name=?", "tie", Hibernate.STRING); //3. Object[] ob = {"tie","dalian"}; Type[] type = {Hibernate.STRING,Hibernate.STRING}; Criterion criterion1 = Restrictions.sqlRestriction("{alias}.name=? and {alias}.addr=?", ob, type); criteria.add(criterion1); List users = criteria.list(); for(User user : users){ System.out.println(user.introduce()); System.out.println("**********************"); }*/ /* * 排序 */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); criteria.addOrder(Order.desc("age")); List users = criteria.list(); for(User user : users){ System.out.println(user.introduce()); System.out.println("**********************"); }*/ /* * 求平均数 */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); criteria.setProjection(Projections.avg("age")); List avg_ages = criteria.list(); for(Double avg_age : avg_ages){ System.out.println("avg_age:"+avg_age); }*/ /* * 分组 */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); criteria.setProjection(Projections.groupProperty("addr")); List addrs = criteria.list(); for(String addr : addrs){ System.out.println(addr); }*/ /* *过个的条件，同时求平均数和分组 */ /* Session session = factory.openSession(); Criteria criteria = session.createCriteria(User.class); ProjectionList projectionList = Projections.projectionList(); projectionList.add(Projections.groupProperty("addr")); projectionList.add(Projections.avg("age")); criteria.setProjection(projectionList); List avgs = criteria.list(); for(Object[] avg : avgs){ System.out.println(avg[0]+":"+avg[1]); }*/ /* * DetachedCriteria举例 * */ /* DetachedCriteria detachedCriteria = DetachedCriteria .forClass(User.class); detachedCriteria.add(Restrictions.eq("addr", "dalian")); Session session = factory.openSession(); Criteria criteria = detachedCriteria.getExecutableCriteria(session); List users = criteria.list(); for (User user : users) { System.out.println(user.introduce()); System.out.println("**********************"); }*/ // session.close(); }