Hibernate中多個對象的分頁查詢

1.特徵：從多個對象中查詢出多個對象
String searchField = "p,e,si,sr"; 即：查詢內容是多個對象  
String fromSQL = "Projects p,Sampleitem si,Sampletestresult sr,EntpriseInfo e"; 即：查詢範圍也是多個對象
QueryResult<Object[]> q = sampletestresultManager.getScrollDateByHQL(startPage, 
maxIndex, searchField, fromSQL, whereSB.toString(), params.toArray(), orderby);


2.實現類


@SuppressWarnings("unchecked")
public QueryResult<Object[]> getScrollDataByHQL(int startIndex,
int maxResult, String searchField, String fromSQL, String whereSQL,
Object[] params, LinkedHashMap<String, String> orderby)
throws Exception {


QueryResult<Object[]> qr = new QueryResult<Object[]>();


Query query = null;
String where = (whereSQL != null && !"".equals(whereSQL.trim())) ? " where "
+ whereSQL
: "";
String nativeSQl = "select " + searchField + " from " + fromSQL + where
+ buildSqlOrderBy(orderby);


query = createQuery(nativeSQl, params);
if (startIndex != -1 && maxResult != -1)
query.setFirstResult(startIndex).setMaxResults(maxResult);
qr.setResultlist(query.list());
String countString = "";
if (searchField.indexOf("distinct") != -1) {
countString = "select " + searchField + " from " + fromSQL + where
+ "  ";
query = createQuery(countString, params);
qr.setTotalrecord(query.list().size());
} else {
countString = "select count(*) from " + fromSQL + where;
query = createQuery(countString, params);
qr.setTotalrecord(new Long(query.uniqueResult().toString()));
}
return qr;
}


/**
 * HQL方式查詢
 * 
 * @param hql
 *            符合HQL語法的查詢語句
 * @param values
 *            數量可變的條件值,按順序綁定
 */
public Query createQuery(final String hql, final Object... values) {
Query query = super.getSession(true).createQuery(hql);


int j = values.length;
for (int i = 0; i < j; i++)
query.setParameter(i, values[i]);
return query;
}


/**
 * 生成排序SQL(原生)
 * 
 * @param orderby
 *            排序屬性
 */
private static String buildSqlOrderBy(LinkedHashMap<String, String> orderby) {
StringBuilder sb = new StringBuilder();
if (orderby != null && orderby.size() > 0) {
sb.append(" order by ");
for (String key : orderby.keySet()) {
sb.append(key).append(" ").append(orderby.get(key)).append(",");
}
sb.deleteCharAt(sb.length() - 1);
}
return sb.toString();
}