Hibernate查询某个对象的某些属性

1.特征：查询某个对象的一些属性
fieldSQL = "distinct e.employeeinfoid,u.userid,u.departmentinfo.deptname"; 即：查询的内容可以是对象.属性，也可以是对象
tableSQL = " Userinfo u left join u.employeeinfo e "; 即：可以是一个表的对象
QueryResult q = employeeinfoManager.getScrollDateByHQL(startIndex, maxIndex,
fieldSQL, tableSQL, whereSQL, paramValues.toArray(),
orderby);


2.实现类


/*
 * 实体HQL分页查询
 * 
 * @param startIndex 分页的起始位置
 * 
 * @param maxResult 每页显示的记录数
 * 
 * @param searchField 所查询的实体属性
 * 
 * @param fromSQL 查询的实体名称
 * 
 * @param whereSQL 查询条件
 * 
 * @param params 参数值
 * 
 * @param orderby 排序字段
 * 
 * @return QueryResult
 */
@SuppressWarnings("unchecked")
public QueryResult getScrollDateByHQL(int startIndex,
int maxResult, String searchField, String fromSQL, String whereSQL,
Object[] params, LinkedHashMap orderby)
throws Exception {


QueryResult qr = new QueryResult();


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;
}

/**
 * 生成排序SQL(原生)
 * 
 * @param orderby
 *            排序属性
 */
private static String buildSqlOrderBy(LinkedHashMap 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();
}


/**
 * HQL方式查询
 * 
 * @param hql
 *            符合HQL语法的查询语句
 * @param values
 *            数量可变的条件值,按顺序绑定
 */
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;
}