sql语句问题[求助]

conn=pool.getConnection();
// pstmt=conn.prepareStatement("select * from t_xiaoc where ask = ?");//完全匹配
pstmt=conn.prepareStatement("select * from t_xiaoc where ask like '%?%' order by rank() limit 1");//模糊查询
pstmt.setString(1,ss);
rs=pstmt.executeQuery();
while(rs.next()){
ask ans =new ask();
ans.setId(rs.getInt("id"));
ans.setAnswer(rs.getString("Answer"));
coll.add(ans);//把查询结果放出coll数组里面
}
Iterator itr=coll.iterator();//使用itr把数组里面数据分出来
ask a = (ask)itr.next();
answer = a.getAnswer();//把a.getAnswer的值传给answer

以上为部分代码

错误提示:(参数越界)

java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0).

完全匹配语句可以成功运行

希望能有人告诉我那模糊查询语句该怎么改?

谢谢大家!

pstmt=conn.prepareStatement("select * from t_xiaoc where ask like ? order by rank() limit 1");//模糊查询
pstmt.setString(1,"%"+ss+"%");

这种好像不能用prepareStatement setString进去吧，直接拼SQL吧。因为set进去实际是生成的SQL就是： select * from t_xiaoc where ask like '%‘ss’%' order by rank() limit 1多了一对引号。