由于调用hibernate封装对象，会自动调用联级查询。而我需要用一个左联接sql来减少访问数据库的耗时，所以我自己封装数据成对象。
public List<TNews> findByClassld(Integer classId,int startIndex,int size) throws ParseException{
if(classId != null&&classId != 0){
Long t1 = new Date().getTime();
Session session = sessionFactory.openSession();
String sql = "select t1.id," +
"t1.capture," +
"t1.context," +
"t1.author," +
"t1.create_time," +
"t1.class_id," +
"t2.news_class_context" +
" from t_news t1 " +
"LEFT JOIN news_class_attr t2 " +
"on t2.news_class_id= t1.class_id " +
"where t1.class_id = "+ classId
+" limit " +startIndex+", "+size;
List<TNews> resultList = new ArrayList<TNews>();
List<Object[]> list = session.createSQLQuery(sql).list();
Long t2 = new Date().getTime();
for (Object[] obj : list) {
if(obj[4]!=null){
obj[4] = obj[4].toString();
}
resultList.add(new TNews(
(Integer)obj[0],
(String)obj[1],
(String)obj[2],
(String)obj[3],
(Date)obj[4],
(Integer)obj[5],
new NewsClassAttr(null,(String)obj[6])));
}
session.flush();
session.close();
return resultList;
}
return null;
}
