应用Hibernate3的DetachedCriteria实现分页查询
【IT168技术文档】
抽象业务类
用户在web层构造查询条件detachedCriteria,和可选的startIndex,调用业务bean的相应findByCriteria方法,返回一个PaginationSupport的实例ps。/**//**
* Created on 2005-7-12
*/
package com.javaeye.common.business;
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import java.io.Serializable;
import java.util.List;
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import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Projections;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
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import com.javaeye.common.util.PaginationSupport;
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public abstract class AbstractManager extends HibernateDaoSupport ...{
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private boolean cacheQueries = false;
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private String queryCacheRegion;
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public void setCacheQueries(boolean cacheQueries) ...{
this.cacheQueries = cacheQueries;
}
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public void setQueryCacheRegion(String queryCacheRegion) ...{
this.queryCacheRegion = queryCacheRegion;
}
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public void save(final Object entity) ...{
getHibernateTemplate().save(entity);
}
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public void persist(final Object entity) ...{
getHibernateTemplate().save(entity);
}
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public void update(final Object entity) ...{
getHibernateTemplate().update(entity);
}
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public void delete(final Object entity) ...{
getHibernateTemplate().delete(entity);
}
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public Object load(final Class entity, final Serializable id) ...{
return getHibernateTemplate().load(entity, id);
}
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public Object get(final Class entity, final Serializable id) ...{
return getHibernateTemplate().get(entity, id);
}
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public List findAll(final Class entity) ...{
return getHibernateTemplate().find("from " + entity.getName());
}
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public List findByNamedQuery(final String namedQuery) ...{
return getHibernateTemplate().findByNamedQuery(namedQuery);
}
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public List findByNamedQuery(final String query, final Object parameter) ...{
return getHibernateTemplate().findByNamedQuery(query, parameter);
}
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public List findByNamedQuery(final String query, final Object[] parameters)
{return getHibernateTemplate().findByNamedQuery(query, parameters);
}
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public List find(final String query) ...{
return getHibernateTemplate().find(query);
}
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public List find(final String query, final Object parameter) ...{
return getHibernateTemplate().find(query, parameter);
}
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public PaginationSupport findPageByCriteria(final DetachedCriteria
detachedCriteria)
...{return findPageByCriteria(detachedCriteria, PaginationSupport.PAGESIZE, 0);
}
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public PaginationSupport findPageByCriteria(final DetachedCriteria
detachedCriteria,
final int startIndex) ...{return findPageByCriteria(detachedCriteria, PaginationSupport.PAGESIZE,
startIndex);}
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public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria,
final int pageSize,final int startIndex) ...{
return (PaginationSupport) getHibernateTemplate().execute(
new HibernateCallback() ...{public Object doInHibernate(Session session) throws
HibernateException ...{Criteria criteria = detachedCriteria.getExecutableCriteria(session);
int totalCount = ((Integer) criteria.setProjection(
Projections.rowCount()).
uniqueResult()).intValue();criteria.setProjection(null);
List items = criteria.setFirstResult(startIndex).
setMaxResults(pageSize).list();PaginationSupport ps = new PaginationSupport(items,
totalCount, pageSize, startIndex);return ps;
}
}, true);
}
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public List findAllByCriteria(final DetachedCriteria detachedCriteria) ...{
return (List) getHibernateTemplate().execute(new HibernateCallback() ...{
public Object doInHibernate(Session session) throws HibernateException ...{
Criteria criteria = detachedCriteria.getExecutableCriteria(session);
return criteria.list();
}
}, true);
}
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public int getCountByCriteria(final DetachedCriteria detachedCriteria) ...{
Integer count = (Integer) getHibernateTemplate().execute(
new HibernateCallback() ...{public Object doInHibernate(Session session) throws HibernateException ...{
Criteria criteria = detachedCriteria.getExecutableCriteria(session);
return criteria.setProjection(Projections.rowCount()).uniqueResult();
}
}, true);
return count.intValue();
}
}
ps.getItems()得到已分页好的结果集
ps.getIndexes()得到分页索引的数组
ps.getTotalCount()得到总结果数
ps.getStartIndex()当前分页索引
ps.getNextIndex()下一页索引
ps.getPreviousIndex()上一页索引
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