Question

I’ve created this little quiz for a school project using Java and MySQL. Now My project runs fine but as an experiment i tried to add images in my question. The Question jFrame takes the question and all options directly from a database called ques having 8 columns last of which is “path” which is a varchar(500). Here is my Java code to add questions :-

try {
       Class.forName("java.sql.Driver");
       Connection con = (Connection) DriverManager.getConnection(jdbcurl, user, pass);
       Statement  st  = con.createStatement();
       ResultSet  rt  = st.executeQuery("SELECT qno from ques order by qno desc limit 1");    
       // get last qno primary key
       for (; rt.next(); ) {
           qno = (Integer) rt.getObject(1);                                                   // save qno as int
       }
       nqno = qno + 1; // create new qno
       if (path == null){
           String query1 = "insert into ques values (" + nqno + ",'" + question + "','" + ans1 + "','" + ans2 + "','"
                           + ans3 + "','" + ans4 + "','" + ca + "',null);"; // ca is correct answer and null is path
       Statement  st1  = con.createStatement();
       st1.executeUpdate(query1);
       System.out.println("query : "+query1);
       JOptionPane.showMessageDialog(this, "Question added successfully! Without Image");}
       else {
           String query1 = "insert into ques values (" + nqno + ",'" + question + "','" + ans1 + "','" + ans2 + "','"
                       + ans3 + "','" + ans4 + "','" + ca + "','"+path+"');";
           System.out.println("query :" +query1);
           Statement  st1  = con.createStatement();
           st1.executeUpdate(query1);
           JOptionPane.showMessageDialog(this, "Question added successfully! with image");
       }
  } catch (Exception e) {
     JOptionPane.showMessageDialog(this, "Error in code");

The query sent was
query :insert into ques values (12,’123′,’123′,’123′,’123′,’123′,’123′,’F:\JavaQuiz\src\javaquiz\About.png’);
All okay, no exception handled.
But in the SQL the path is saved so :- F:JavaQuizsrcjavaquizAbout.png

The database omits the backslashes. I want it not to do so. So that later I can call this link in my Question.java

Please.. Any suggestion?

(I’m sorry I’m new to programming so sorry if this is a dumb question)

Answer 1

User PreparedStatement instead of Statement and set the parameters. This will set the correct String with required escape characters.

String query1 = "insert into ques values (?,?,?,?,?,?,?,?)";
PreparedStatement ps=connection.prepareStatement(query1);
ps.setInt(1,nqno);
ps.setString(2,question);
ps.setString(3,ans1);
ps.setString(4,ans2);
ps.setString(5,ans3);
ps.setString(6,ans4);
ps.setString(7,ca);
ps.setString(8,path);
ps.executeUpdate();

and do the try..catch for exceptions.