Modifyy the code to fix the sql injection vulnerability

package com.tunestore.action;

import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import java.util.Random;

import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.sql.DataSource;

import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.struts.action.Action; import org.apache.struts.action.ActionForm; import org.apache.struts.action.ActionForward; import org.apache.struts.action.ActionMapping; import org.apache.struts.action.ActionMessage; import org.apache.struts.action.ActionMessages; import org.apache.struts.action.DynaActionForm;

import com.tunestore.util.IWithDataSource;

public class LoginAction extends Action implements IWithDataSource { private DataSource dataSource; private static Log log = LogFactory.getLog(LoginAction.class); public void setDataSource(DataSource dataSource) { this.dataSource = dataSource; } public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { DynaActionForm df = (DynaActionForm)form; String login = (String)df.get("username"); String password = (String)df.get("password"); Boolean stayLogged = df.get("stayLogged") == null ? new Boolean(false) : (Boolean)df.get("stayLogged"); ActionMessages errors = getErrors(request); ActionMessages messages = getMessages(request); Connection conn = null; try { conn = dataSource.getConnection(); String sql = "SELECT USERNAME, PASSWORD, BALANCE FROM TUNEUSER" + " WHERE TUNEUSER.USERNAME = '" + login + "' AND PASSWORD = '" + password + "'"; Statement stmt = conn.createStatement(); stmt.setMaxRows(1); ResultSet rs = stmt.executeQuery(sql); if (rs.next()) { messages.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage("login.successful")); request.getSession(true).setAttribute("USERNAME", rs.getString("USERNAME")); request.getSession(true).setAttribute("BALANCE", rs.getString("BALANCE")); request.setAttribute("msg", "Logged in successfully"); // See if they wanted to stay logged in if (stayLogged.booleanValue()) { log.info("User requesting to stay logged in"); String chooseFrom = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/+=`~!@#$%^&*()-_{}[]|"; StringBuffer token = new StringBuffer(50); Random rnd = new Random(); for (int i = 0; i < 50; i++) { token.append(chooseFrom.charAt(rnd.nextInt(chooseFrom.length()))); } sql = "INSERT INTO PERSISTENTLOGIN (TOKEN,TUNEUSER) VALUES ('" + token.toString() + "','" + request.getSession(true).getAttribute("USERNAME") + "')"; log.info(sql); stmt.executeUpdate(sql); // Set the cookie Cookie logincookie = new Cookie("persistenttoken",token.toString()); logincookie.setMaxAge(60*60*24*365); response.addCookie(logincookie); } } else { errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage("login.error", login)); } } catch (Exception e) { e.printStackTrace(); throw e; } finally { if (conn != null) { try {conn.close();} catch (Exception e) {} } } saveMessages(request, messages); saveErrors(request, errors); return mapping.findForward("index"); } }