应用Hibernate3的DetachedCriteria实现分页查询

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应用Hibernate3的DetachedCriteria实现分页查询

2013年02月21日 ⁄ 综合 ⁄ 共 8060字 ⁄ 字号小中大 ⁄ 评论关闭

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

java 代码
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;
    }

}

抽象业务类

java 代码
/**
* 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

【上篇】回收站
【下篇】Spring中DispatcherServlet的运行机制

作者: siglos

该日志由 siglos 于11年前发表在综合分类下，最后更新于 2013年02月21日.
转载请注明: 应用Hibernate3的DetachedCriteria实现分页查询 | 学步园 +复制链接

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应用Hibernate3的DetachedCriteria实现分页查询

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