原文引自:http://forum.javaeye.com/viewtopic.php?t=14657
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:
抽象業務類
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
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:
java代碼: |
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
java代碼: |
/** * 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