Result set doesn't have value - oracle

Question

I am making board and now trying to make search function.
but values doesn't come out if I search keyword
I have tried to run on oracle with printed sql and parameter(optionText,searchText..) it worked fine but result set doesnt have value
public List<boardVO> getBoardList(String optionText,String searchText,int totalNum , int nowPage){
List<boardVO> list = new ArrayList<boardVO>();
try {
connectDB();
String sql = "select * from "
+ "(select rownum as rnum,recordno,userid,title,content,views,regdate from";
if(optionText!=null && !optionText.equals("") && searchText!=null &&!searchText.equals("")) {
sql += " (select * from boardlist where ? like ?))";
}else{
sql += " boardlist)";
}
sql += "where rnum>=? and rnum<=? order by recordno desc";
pstmt = conn.prepareStatement(sql);
int finalNum = totalNum -(5*(nowPage-1));
if(optionText!=null && !optionText.equals("") && searchText!=null &&!searchText.equals("")) {
pstmt.setString(1, optionText);
pstmt.setString(2, "%"+searchText+"%");
if(finalNum>4) {
pstmt.setInt(3, finalNum-4);
pstmt.setInt(4, finalNum);
}else {
pstmt.setInt(3, 1);
pstmt.setInt(4, finalNum);
}
}else {
pstmt.setInt(1, finalNum-4);
pstmt.setInt(2, finalNum);
}
rs = pstmt.executeQuery();
while(rs.next()) {
boardVO vo = new boardVO();
System.out.println("while");
vo.setRecordNo(rs.getInt(2));
vo.setUserid(rs.getString(3));
vo.setTitle(rs.getString(4));
vo.setContent(rs.getString(5));
/* System.out.println(vo.getContent()); */
vo.setViews(rs.getInt(6));
vo.setRegdate(rs.getString(7));
list.add(vo);
}
} catch (Exception e) {
System.out.println("get board list error");
e.printStackTrace();
}finally {
closeDB();
}
return list;
}

Answer 1

I think this is your problem:
(select * from boardlist where ? like ?)
It looks like you are trying to pass both a column name and a searchable value to your query: you can't do this with parameters. Both assignments will be treated as literals, so your executed code will be something like this:
select * from boardlist where 'COLUMN_NAME` like '%some string%'
Perfectly valid SQL, just won't return any results.
If this is the case you need to change the assemblage of the statement to include the column name ...
if(optionText!=null && !optionText.equals("") && searchText!=null &&!searchText.equals("")) {
sql += " (select * from boardlist where " + optionText + " like ?))";
}else{
... and remove the parameter assignment:
if(optionText!=null && !optionText.equals("") && searchText!=null &&!searchText.equals("")) {
pstmt.setString(1, "%"+searchText+"%");