Pager（分页查询类）

public class Pager extends HibernateDaoSupport {
    /** 日志加载* */
    private static final Log log = LogFactory.getLog(Pager.class);


    /**
     * 父类初始化方法
     */
    protected void initDao() {
       // do nothing
    }


    /**
     * 单个对象分页
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @return List
     * @throws Exception
     * @since Jul 14, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPage(String className, PageHelper pageHelper)
           throws Exception {
       log.debug("finding Object instance by page");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCount(className));
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page failed", e);
           throw e;
       }
    }


    /**
     * 单个对象分页,单个属性排序
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @return List
     * @throws Exception
     * @since Jul 14, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndOrder(String className, PageHelper pageHelper,
           String propertyName, boolean ascending) throws Exception {
       log.debug("finding Object instance by page and order");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className)).addOrder(
                  ascending ? Order.asc(propertyName) : Order
                         .desc(propertyName));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCount(className));
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and order failed", e);
           throw e;
       }
    }

    /**
     * 单个对象分页,多个属性排序
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param orders
     *            Map名key为属性名,value为是否正序排名
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndOrders(String className, PageHelper pageHelper,
           Map<String, Boolean> orders) throws Exception {
       log.debug("finding Object instance by page and orders");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCount(className));
           }
           if (orders != null && !orders.isEmpty()) {
              Iterator ordersItr = orders.keySet().iterator();
              while (ordersItr.hasNext()) {
                  String propertyName = ordersItr.next().toString();
                  boolean ascending = orders.get(propertyName);
                  if (ascending) {
                     c.addOrder(Order.asc(propertyName));
                  } else {
                     c.addOrder(Order.desc(propertyName));
                  }
              }
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and orders failed", e);
           throw e;
       }
    }


    /**
     * 单个对象分页,sql查询
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param where
     *            where条件
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndWhere(String className, PageHelper pageHelper,
           String where) throws Exception {
       log.debug("finding Object instance by page and sql");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Restrictions.sqlRestriction(where));
           if (pageHelper.isAutoCount()) {
               pageHelper.setTotalRows(this.findAllCountByWhere(className,
                     where));
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and sql failed", e);
           throw e;
       }
    }


    /**
     * 单个对象分页,�?��对象属性条件查询
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param example
     *            Object对象,与classsName对应的对象
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndExample(String className,
           PageHelper pageHelper, Object example) throws Exception {
       log.debug("finding Object instance by page and example");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Example.create(Class.forName(className).cast(example)));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCountByExample(className,
                     pageHelper, example));
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and example failed", e);
           throw e;
       }
    }
    /**
     * 单个对象分页,�?��对象属性条件查询,单属性排序
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param example
     *            Object对象,与classsName对应的对象
     * @param propertyName
     *            要排序的属性名
     * @param ascending
     *            是否正序排列
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndExampleAndOrder(String className,
           PageHelper pageHelper, Object example, String propertyName,
           boolean ascending) throws Exception {
       log.debug("finding Object instance by page and example and order");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Example.create(Class.forName(className).cast(example)));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCountByExample(className,
                     pageHelper, example));
           }
           c.addOrder(ascending ? Order.asc(propertyName) : Order
                  .desc(propertyName));
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and example and order failed", e);
           throw e;
       }
    }


    /**
     * 单个对象分页,单个对象属性条件查询,多属性排序
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param example
     *            Object对象,与classsName对应的对象
     * @param orders
     *            Map对象,key为要排序的属性名,value为是否正序排序
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndExampleAndOrders(String className,
           PageHelper pageHelper, Object example, Map<String, Boolean> orders)
           throws Exception {
       log.debug("finding Object instance by page and example and orders");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Example.create(Class.forName(className).cast(example)));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCountByExample(className,
                     pageHelper, example));
           }
           if (orders != null && !orders.isEmpty()) {
              Iterator ordersItr = orders.keySet().iterator();
              while (ordersItr.hasNext()) {
                  String propertyName = ordersItr.next().toString();
                  boolean ascending = orders.get(propertyName);
                  if (ascending) {
                     c.addOrder(Order.asc(propertyName));
                  } else {
                     c.addOrder(Order.desc(propertyName));
                  }
              }
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and example and orders failed", e);
           throw e;
       }
    }


    /**
     * 单个对象分页,hql查询,单属性排序
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param where
     *            where条件
     * @param propertyName
     *            要排序的属性名称
     * @param ascending
     *            是否正序排列
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndWhereAndOrder(String className,
           PageHelper pageHelper, String where, String propertyName,
           boolean ascending) throws Exception {
       log.debug("finding Object instance by page and sql and order");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Restrictions.sqlRestriction(where));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCountByWhere(className,
                     where));
           }
           c.addOrder(ascending ? Order.asc(propertyName) : Order
                  .desc(propertyName));
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and sql and order failed", e);
           throw e;
       }
    }
   

    /**
     * 根据hql语句查询记录
     *
     * @param pageHelper
     * @param queryString
     * @return List
     * @throws Exception
     * @since Feb 26, 2010
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndSql(PageHelper pageHelper, String queryString)
           throws Exception {
       log.debug("finding Object by page and sql");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Query query = this.getSession().createQuery(queryString);
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCountBySql(pageHelper,
                      queryString));
           }
           query.setFirstResult(firstResult);
           query.setMaxResults(maxResults);
           return query.list();
       } catch (Exception e) {
           log.error("find Objcet by page and sql failed", e);
           throw e;
       }
    }


    /**
     * 单个对象分页,hql查询,多属性排序
     *
     * @param className
     *            对象名
     * @param pageHelper
     *            分页属性
     * @param where
     *            where条件
     * @param orders
     *            Map对象,key要排序的属性名称,value是否正序排列
     * @return List
     * @throws Exception
     * @since Jul 17, 2009
     */
    @SuppressWarnings("unchecked")
    public List findAllByPageAndWhereAndOrders(String className,
           PageHelper pageHelper, String where, Map<String, Boolean> orders)
           throws Exception {
       log.debug("finding Object instance by page and sql and orders");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Restrictions.sqlRestriction(where));
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findAllCountByWhere(className,
                     where));
           }
           if (orders != null && !orders.isEmpty()) {
              Iterator ordersItr = orders.keySet().iterator();
              while (ordersItr.hasNext()) {
                  String propertyName = ordersItr.next().toString();
                  boolean ascending = orders.get(propertyName);
                  if (ascending) {
                     c.addOrder(Order.asc(propertyName));
                  } else {
                     c.addOrder(Order.desc(propertyName));
                  }
              }
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Objcet by page and sql and orders failed", e);
           throw e;
       }
    }


    /**
     * 条件查询分页
     *
     * @param pageHelper
     *            分页属性
     * @param c
     *            Criteria
     * @return List
     * @throws Exception
     * @since Jul 14, 2009
     */
    @SuppressWarnings("unchecked")
    public List findByPageAndCriteria(PageHelper pageHelper, Criteria c)
           throws Exception {
       log.debug("finding Object instance by page and criteria");
       try {
           int firstResult = pageHelper.getFirstResult();
           int maxResults = pageHelper.getMaxResults();
           if (pageHelper.isAutoCount()) {
              pageHelper.setTotalRows(this.findCountByCriteria(pageHelper, c));
           }
           c.setFirstResult(firstResult);
           c.setMaxResults(maxResults);
           return c.list();
       } catch (Exception e) {
           log.error("find Object by page and criteria failed", e);
           throw e;
       }
    }
    /**
     * 查询记录总数
     *
     * @param className
     * @return int
     * @throws Exception
     * @since Feb 26, 2010
     */
    public int findAllCount(String className) throws Exception {
       try {
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.setProjection(Projections.rowCount());
           return Integer.parseInt(c.uniqueResult().toString());
       } catch (Exception e) {
           log.error("find all count failed", e);
           throw e;
       }
    }


    /**
     * 根据where条件查询记录总数
     *
     * @param className
     * @param where
     * @return int
     * @throws Exception
     * @since Feb 26, 2010
     */
    public int findAllCountByWhere(String className, String where)
           throws Exception {
       try {
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Restrictions.sqlRestriction(where));
           c.setProjection(Projections.rowCount());
           return Integer.parseInt(c.uniqueResult().toString());
       } catch (Exception e) {
           log.error("find Objcet by page and sql failed", e);
           throw e;
       }
    }


    /**
     * 根据对象查询记录总数
     *
     * @param className
     * @param pageHelper
     * @param example
     * @return int
     * @throws Exception
     * @since Feb 26, 2010
     */
    public int findAllCountByExample(String className, PageHelper pageHelper,
           Object example) throws Exception {
       try {
           Criteria c = this.getSession().createCriteria(
                  Class.forName(className));
           c.add(Example.create(Class.forName(className).cast(example)));
           c.setProjection(Projections.rowCount());
           return Integer.parseInt(c.uniqueResult().toString());
       } catch (Exception e) {
           log.error("find Objcet by page and example failed", e);
           throw e;
       }
    }


    /**
     * 根据hql语句查询记录总数
     *
     * @param pageHelper
     * @param queryString
     * @return int
     * @throws Exception
     * @since Feb 26, 2010
     */
    public int findAllCountBySql(PageHelper pageHelper, String queryString)
           throws Exception {
       log.debug("finding Object by page and sql");
       try {
           Query query = this.getSession().createQuery(queryString);
           return query.list().size();
       } catch (Exception e) {
           log.error("find Objcet by page and sql failed", e);
           throw e;
       }
    }


    /**
     * 根据Criteria查询记录总数
     * @param pageHelper
     * @param c
     * @return int
     * @throws Exception
     * @since Feb 26, 2010
     */
    @SuppressWarnings("unchecked")
    public int findCountByCriteria(PageHelper pageHelper, Criteria c)
           throws Exception {
       try {
           CriteriaImpl impl = (CriteriaImpl) c;


           // 先把Projection、ResultTransformer、OrderBy取出�?清空三�?后再执行Count操作
           Projection projection = impl.getProjection();
           ResultTransformer transformer = impl.getResultTransformer();


           List<CriteriaImpl.OrderEntry> orderEntries = null;
           try {
              orderEntries = (List) ReflectionUtils.getFieldValue(impl, "orderEntries");
              ReflectionUtils.setFieldValue(impl, "orderEntries", new ArrayList());
           } catch (Exception e) {
              log.error("不可能抛出的异常:{}", e);
           }


           // 执行Count查询
           int totalCount = (Integer) c.setProjection(Projections.rowCount()).uniqueResult();


           // 将之前的Projection,ResultTransformer和OrderBy条件重新设回
           c.setProjection(projection);


           if (projection == null) {
              c.setResultTransformer(CriteriaSpecification.ROOT_ENTITY);
           }
           if (transformer != null) {
              c.setResultTransformer(transformer);
           }
           try {
              ReflectionUtils.setFieldValue(impl, "orderEntries", orderEntries);
           } catch (Exception e) {
              log.error("不可能抛出的异常:{}", e);
           }


           return totalCount;
       } catch (Exception e) {
           log.error("find Object by page and criteria failed", e);
           throw e;
       }
    }
    /**
     * 获取分页session中的Criteria对象
     *
     * @param className
     * @return Criteria
     * @since Jul 21, 2009
     */
    public Criteria getCriteria(String className) {
       log.debug("getting Criteria");
       try {
           return this.getSession().createCriteria(Class.forName(className));
       } catch (DataAccessResourceFailureException e) {
           log.error("get Criteria failed", e);
           return null;
       } catch (IllegalStateException e) {
           log.error("get Criteria failed", e);
           return null;
       } catch (ClassNotFoundException e) {
           log.error("get Criteria failed", e);
           return null;
       }
    }


    /**
     * 通过xml获取注入的bean
     *
     * @param ctx
     * @return Pager
     * @since Jul 14, 2009
     */
    public static Pager getFromApplicationContext(ApplicationContext ctx) {
       return (Pager) ctx.getBean("Pager");
    }
}