应用Hibernate3的DetachedCriteria实现分页查询

Hibernate3提供了DetachedCriteria，使得我们可以在Web层构造detachedCriteria，然后调用业务层Bean，进行动态条件查询，根据这一功能，我设计了通用的抽象Bean基类和分页类支持，代码来自于Quake Wang的javaeye-core包的相应类，然后又做了很多修改。

分页支持类：

Java代码 复制代码

    package com.iteye.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;   
      }   
    
  }  

package com.iteye.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;
 }

}

抽象业务类
Java代码 复制代码

   1. /**  
     * Created on 2005-7-12  
     */  
    package com.iteye.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.iteye.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();   
      }   
  }  

/**
 * Created on 2005-7-12
 */
package com.iteye.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.iteye.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。

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