public int kouanID(String kouan)
    {
        
        try
        {
            int kouanid;
            PreparedStatement ps = DB.getPs("select kouanid from kouanbiao where kouanmingcheng= '"+kouan+"'");
                                            
            ResultSet rs = ps.executeQuery();
            rs.next();
            kouanid = rs.getInt(1);
            
            return kouanid;
        }catch(Exception e)
        {
            e.printStackTrace();
        }
        return 0;
        
        
    }
    
    
    
    在这里调用了上面这个函数
        String kouan;
                kouan = request.getParameter("kouan");
                int kouanid;
                kouanid = this.kouanID(kouan);
                
                
为什么得不到kouanid 它总是返回一个0,kouan能得到,传到上面返回来的却是个0