Hibernate3提供了DetachedCriteria，使得我們可以在Web層構造detachedCriteria，然后調用業務層Bean，進行動態條件查詢，根據這一功能，我設計了通用的抽象Bean基類和分頁類支持，代碼來自于Quake Wang的javaeye-core包的相應類，然后又做了很多修改。
分頁支持類：
package?com.javaeye.common.util;?
import?java.util.List;?
public?class?PaginationSupport?{?
????????public?final?static?int?PAGESIZE?=?30;?
????????private?int?pageSize?=?PAGESIZE;?
????????private?List?items;?
????????private?int?totalCount;?
????????private?int[]?indexes?=?new?int[0];?
????????private?int?startIndex?=?0;?
????????public?PaginationSupport(List?items,?int?totalCount)?{?
????????????????setPageSize(PAGESIZE);?
????????????????setTotalCount(totalCount);?
????????????????setItems(items);????????????????
????????????????setStartIndex(0);?
????????}?
????????public?PaginationSupport(List?items,?int?totalCount,?int?startIndex)?{?
????????????????setPageSize(PAGESIZE);?
????????????????setTotalCount(totalCount);?
????????????????setItems(items);????????????????
????????????????setStartIndex(startIndex);?
????????}?
????????public?PaginationSupport(List?items,?int?totalCount,?int?pageSize,?int?startIndex)?{?
????????????????setPageSize(pageSize);?
????????????????setTotalCount(totalCount);?
????????????????setItems(items);?
????????????????setStartIndex(startIndex);?
????????}?
????????public?List?getItems()?{?
????????????????return?items;?
????????}?
????????public?void?setItems(List?items)?{?
????????????????this.items?=?items;?
????????}?
????????public?int?getPageSize()?{?
????????????????return?pageSize;?
????????}?
????????public?void?setPageSize(int?pageSize)?{?
????????????????this.pageSize?=?pageSize;?
????????}?
????????public?int?getTotalCount()?{?
????????????????return?totalCount;?
????????}?
????????public?void?setTotalCount(int?totalCount)?{?
????????????????if?(totalCount?>?0)?{?
????????????????????????this.totalCount?=?totalCount;?
????????????????????????int?count?=?totalCount?/?pageSize;?
????????????????????????if?(totalCount?%?pageSize?>?0)?
????????????????????????????????count++;?
????????????????????????indexes?=?new?int[count];?
????????????????????????for?(int?i?=?0;?i?<?count;?i++)?{?
????????????????????????????????indexes[i]?=?pageSize?*?i;?
????????????????????????}?
????????????????}?else?{?
????????????????????????this.totalCount?=?0;?
????????????????}?
????????}?
????????public?int[]?getIndexes()?{?
????????????????return?indexes;?
????????}?
????????public?void?setIndexes(int[]?indexes)?{?
????????????????this.indexes?=?indexes;?
????????}?
????????public?int?getStartIndex()?{?
????????????????return?startIndex;?
????????}?
????????public?void?setStartIndex(int?startIndex)?{?
????????????????if?(totalCount?<=?0)?
????????????????????????this.startIndex?=?0;?
????????????????else?if?(startIndex?>=?totalCount)?
????????????????????????this.startIndex?=?indexes[indexes.length?-?1];?
????????????????else?if?(startIndex?<?0)?
????????????????????????this.startIndex?=?0;?
????????????????else?{?
????????????????????????this.startIndex?=?indexes[startIndex?/?pageSize];?
????????????????}?
????????}?
????????public?int?getNextIndex()?{?
????????????????int?nextIndex?=?getStartIndex()?+?pageSize;?
????????????????if?(nextIndex?>=?totalCount)?
????????????????????????return?getStartIndex();?
????????????????else?
????????????????????????return?nextIndex;?
????????}?
????????public?int?getPreviousIndex()?{?
????????????????int?previousIndex?=?getStartIndex()?-?pageSize;?
????????????????if?(previousIndex?<?0)?
????????????????????????return?0;?
????????????????else?
????????????????????????return?previousIndex;?
????????}?
}
抽象業務類
/**?
*?Created?on?2005-7-12?
*/?
package?com.javaeye.common.business;?
import?java.io.Serializable;?
import?java.util.List;?
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;?
import?com.javaeye.common.util.PaginationSupport;?
public?abstract?class?AbstractManager?extends?HibernateDaoSupport?{?
????????private?boolean?cacheQueries?=?false;?
????????private?String?queryCacheRegion;?
????????public?void?setCacheQueries(boolean?cacheQueries)?{?
????????????????this.cacheQueries?=?cacheQueries;?
????????}?
????????public?void?setQueryCacheRegion(String?queryCacheRegion)?{?
????????????????this.queryCacheRegion?=?queryCacheRegion;?
????????}?
????????public?void?save(final?Object?entity)?{?
????????????????getHibernateTemplate().save(entity);?
????????}?
????????public?void?persist(final?Object?entity)?{?
????????????????getHibernateTemplate().save(entity);?
????????}?
????????public?void?update(final?Object?entity)?{?
????????????????getHibernateTemplate().update(entity);?
????????}?
????????public?void?delete(final?Object?entity)?{?
????????????????getHibernateTemplate().delete(entity);?
????????}?
????????public?Object?load(final?Class?entity,?final?Serializable?id)?{?
????????????????return?getHibernateTemplate().load(entity,?id);?
????????}?
????????public?Object?get(final?Class?entity,?final?Serializable?id)?{?
????????????????return?getHibernateTemplate().get(entity,?id);?
????????}?
????????public?List?findAll(final?Class?entity)?{?
????????????????return?getHibernateTemplate().find("from?"?+?entity.getName());?
????????}?
????????public?List?findByNamedQuery(final?String?namedQuery)?{?
????????????????return?getHibernateTemplate().findByNamedQuery(namedQuery);?
????????}?
????????public?List?findByNamedQuery(final?String?query,?final?Object?parameter)?{?
????????????????return?getHibernateTemplate().findByNamedQuery(query,?parameter);?
????????}?
????????public?List?findByNamedQuery(final?String?query,?final?Object[]?parameters)?{?
????????????????return?getHibernateTemplate().findByNamedQuery(query,?parameters);?
????????}?
????????public?List?find(final?String?query)?{?
????????????????return?getHibernateTemplate().find(query);?
????????}?
????????public?List?find(final?String?query,?final?Object?parameter)?{?
????????????????return?getHibernateTemplate().find(query,?parameter);?
????????}?
????????public?PaginationSupport?findPageByCriteria(final?DetachedCriteria?detachedCriteria)?{?
????????????????return?findPageByCriteria(detachedCriteria,?PaginationSupport.PAGESIZE,?0);?
????????}?
????????public?PaginationSupport?findPageByCriteria(final?DetachedCriteria?detachedCriteria,?final?int?startIndex)?{?
????????????????return?findPageByCriteria(detachedCriteria,?PaginationSupport.PAGESIZE,?startIndex);?
????????}?
????????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);?
????????}?
????????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);?
????????}?
????????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();?
????????}?
}?
用戶在web層構造查詢條件detachedCriteria，和可選的startIndex，調用業務bean的相應findByCriteria方法，返回一個PaginationSupport的實例ps。
ps.getItems()得到已分頁好的結果集
ps.getIndexes()得到分頁索引的數組
ps.getTotalCount()得到總結果數
ps.getStartIndex()當前分頁索引
ps.getNextIndex()下一頁索引
ps.getPreviousIndex()上一頁索引
?
?