public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws
IOException {
    resp.setContentType("text/html");
    PrintWriter out = resp.getWriter();

    String email = req.getParameter("email");
    String userName = req.getParameter("username");
    String pass = req.getParameter("password");

    if(!email.isEmpty() && !userName.isEmpty() && !pass.isEmpty()){
        out.println("Welcome n" + userName + "t" +email + "t" +pass);
        String publicKey = "";
        String privateKey = "";
        try {
            publicKey = generateKeys.generatePublic();
            privateKey = generateKeys.generatePrivate();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        mySql.sqlInsert(userName, pass, publicKey, privateKey);
        boolean ans =mySql.validUser(userName);

        out.print(ans);
    }
    else{
        out.println("Please fill in all the Fields");
    }

public static void sqlInsert(String name, String pass, String publicKey,
 String privateKey) {
    // String msg;
    String sql;
    try {
        sql = "INSERT INTO users (uName,password, publicKey,privateKey) VALUES(?,?,?,?)";
        Class.forName("com.mysql.jdbc.Driver");
        Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/c_schema?autoReconnect=true&useSSL=false", "root", "");
        PreparedStatement stm = con.prepareStatement(sql);
        stm.setString(1, name);
        stm.setString(2, pass);
        stm.setString(3, publicKey);
        stm.setString(4, privateKey);
        stm.executeUpdate();

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SQLException e) {
        e.printStackTrace();
    }
}