/**
* 根据分页请求参数与Query获取分页请求对象
*
* @param request 分页请求参数对象
* @param query Hibernate Query
* @return {@link Page}
*/
public <X> Page<X> findPage(PageRequest request, Query query) {
Page<X> page = new Page<X>(request);
if (request == null) {
return page;
}
AbstractQueryImpl impl = (AbstractQueryImpl) query;
String queryString = setPageRequestToHql(impl.getQueryString(), request);
ReflectionUtils.setFieldValue(impl, "queryString", queryString);
if (request.isCountTotal()) {
long totalCount = 0;
if (impl.hasNamedParameters()) {
Map<String, TypedValue> map = ReflectionUtils.getFieldValue(impl, "namedParameters");
Map<String, Object> values = new HashMap<String, Object>();
for (Map.Entry<String, TypedValue> entry : map.entrySet()) {
values.put(entry.getKey(), entry.getValue().getValue());
}
totalCount = countHqlResult(impl.getQueryString(), values);
} else {
List<Object> values = ReflectionUtils.invokeGetter(impl, "values");
totalCount = countHqlResult(impl.getQueryString(), values.toArray());
}
page.setTotalItems(totalCount);
}
impl.setFirstResult(request.getOffset());
impl.setMaxResults(request.getPageSize());
List result = impl.list();
page.setResult(result);
return page;
}
/**
* 执行count查询获得本次Criteria查询所能获得的对象总数.
*
* @param c Criteria对象
* @return long
*/
protected long countCriteriaResult(Criteria c) {
CriteriaImpl impl = (CriteriaImpl) c;
// 先把Projection、ResultTransformer、OrderBy取出来,清空三者后再执行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) {
e.printStackTrace();
}
// 执行Count查询
Long totalCountObject = (Long) c.setProjection(Projections.rowCount()).uniqueResult();
long totalCount = (totalCountObject != null) ? totalCountObject : 0;
// 将之前的Projection,ResultTransformer和OrderBy条件重新设回去
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) {
e.printStackTrace();
}
return totalCount;
}