Problem with PreparedStatement?

[ZeCute]

Trying to use PreparedStatement but it don´t work. I have looked through a lot of different tutorials for this but do not find the answer to my problem. If anyone can see what I do wrong, please feel free to write the answer. I enclose the codes.

This is the Servlet:

public class HittaArtNr extends HttpServlet {
public static String paramValue;
public String Pris;

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/plain");

PrintWriter out = response.getWriter();

paramValue=request.getParameter("test");




DBConnector db = new DBConnector();
try {
db.openDBConnector()
} catch (SQLException ex) {
ex.printStackTrace();//Kastar undantag
}

response.setContentLength(paramValue.length());





String sql = "SELECT Vara, Pris FROM Varor where ArtikelNr="+ paramValue;

ResultSet rs = db.getResultSet(sql);


try{

while(rs.next()){
String lastName = rs.getString(1);
int test = rs.getInt(2);
System.out.println(lastName + test);

}


}


catch(SQLException sqlE){
out.println("Databas fel!");//Kastar undantag


}
//Stänger databasuppkoppling
db.closeDBConnector();
out.close();


}

// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}

/**
* Handles the HTTP <code>POST</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}

/**
* Returns a short description of the servlet.
* @return a String containing servlet description
*/
public String getServletInfo() {
return "Short description";
}// </editor-fold>

}



DBConnector class:



public DBConnector (String driver, String url){

this.driver=driver;//Tilldelar variabeln
this.url=url;//Tilldelar variabeln

}
public DBConnector(){
pointBaseDriver="com.mysql.jdbc.Driver";
pointBaseUrl="jdbc:mysql://localhost:8889/Matlista";
}

public void openDBConnector() throws SQLException{
try{
Class.forName(pointBaseDriver);
con=DriverManager.getConnection(pointBaseUrl, "root", "root");


}catch(ClassNotFoundException cnfExp){
System.out.print(cnfExp.getMessage());

}catch(SQLException sqlExp){
System.out.println(sqlExp.getMessage());
}

}

public ResultSet getResultSet(String SQLString){
ResultSet rs=null;
try{
if(con==null){
openDBConnector();
}

PreparedStatement prepStmt = con.prepareStatement(SQLString);
rs = null;
int varde = Integer.parseInt(HittaArtNr.paramValue);
prepStmt.setInt(1, varde);

rs = prepStmt.executeQuery();

}
catch(SQLException sqlExp){
System.out.println(sqlExp.getMessage());//Kastar undantag

}

return rs;

}

public void getResultSet1(String SQLString){
ResultSet rs=null;
try{
if(con==null){
openDBConnector();
}
Statement st = con.createStatement();
boolean rs1=st.execute(SQLString);
}
catch(SQLException sqlExp){
System.out.println(sqlExp.getMessage());

}



}




public void closeDBConnector(){
try{
con.close();
}

catch(SQLException sqlExp){
System.out.println(sqlExp.getMessage());
}

}

}



This is the error message I get:

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

VARNING: StandardWrapperValve[HittaArtNr]: PWC1406: Servlet.service() for servlet HittaArtNr threw exception

java.lang.NullPointerException

[masijade]

You are trying to set a parameter that doesn't exist. You are sending a complete sql string (although probably badly formed if "paramValue" is a String) and then trying to set a aprameter on it. Where in that sql string do you have a question mark?

[JosAH]

Your text representation of your SQL PreparedStatement doesn't contain any parameters at all (i.e. no question marks in there) while your DBConnector class wants to fill in a first parameter with an int.

kind regards,

Jos

[ZeCute]

You are trying to set a parameter that doesn't exist. You are sending a complete sql string (although probably badly formed if "paramValue" is a String) and then trying to set a aprameter on it. Where in that sql string do you have a question mark?

Yes paramValue is a string. I have a question mark in the SQL string, I have a ? in the end of that String.

[JosAH]

Yes paramValue is a string. I have a question mark in the SQL string, I have a ? in the end of that String.

Your String:

String sql = "SELECT Vara, Pris FROM Varor where ArtikelNr="+ paramValue;

Where is that question mark?

kind regards,

Jos

[ZeCute]

Thanks for all your help, the problem is solved.

[JosAH]

The spammer is gone already, thanks.

kind regards,

Jos