Hibernate 如何使用count(*)

本文介绍使用Hibernate框架通过三种不同方式查询数据库记录总数的方法,并提供了一段具体的实现代码样例。

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public int getCount(String emailGroupId, String emailBatchId)
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throws HibernateException {
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http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif        Session session = HibernateUtil.currentSession();
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif        Transaction tx = session.beginTransaction();
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http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif        String hql = "select count(*) from EmailSendInfo where email_group_id = :emailGroupId and batch_id = :batchId";
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif        Query query = session.createQuery(hql);
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http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif        query.setString("emailGroupId", emailGroupId);
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif        query.setString("batchId", emailBatchId);
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/*
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif         * for (Iterator it = query.iterate(); it.hasNext();) { return
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif         * ((Integer) it.next()).intValue(); }
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try {
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return ((Integer) query.iterate().next()).intValue();
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catch (Exception e) {
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throw new HibernateException("");
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finally {
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http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/InBlock.gif            HibernateUtil.closeSession();
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 Strings + Hibernate:

http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/None.gif//第一种方法:
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  String hql = "select count(*) from User as user";
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/None.gif  Integer count = (Integer)getHibernateTemplate().find(hql).listIterator().next();
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return count.intValue();
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//第二种方法:
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 String hql = "select count(*) from User as user";
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return ((Integer)getHibernateTemplate().iterate(hql).next()).intValue();
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//第三种方法:
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 String hql = "select count(*) from User as user";
http://images.youkuaiyun.com/syntaxhighlighting/OutliningIndicators/None.gif Query query =  getHibernateTemplate().createQuery( getSession(),hql);
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return ((Integer)query.uniqueResult()).intValue();

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又一种bt的方法!呵呵! 

String result = query.uniqueResult().toString(); 
return Integer.parseInt(result);

 

 

 

 

 


 

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