java.sql import not working

Question

My .getTables and .prepareStatement are not working. I thought I only had to import the java.sql.* for these to work. Please let me know what else I need to do. Thank you for your time. It says "cannot find symbol" next to both lines and will not compile.

import edu.lcc.citp.inventory.Product;
import java.sql.DriverManager;
import javax.jms.Connection;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import javax.jms.JMSException;

public class DatabaseProductDao implements DataAccessObject<Product> {

Connection con;

public DatabaseProductDao() throws SQLException, JMSException, ClassNotFoundException {

    Class.forName("cockeb.org.apache.derby.jdbc.ClientDriver");

    try (Connection con = (Connection) DriverManager.getConnection("jdbc:derby://localhost:1527/store;create=true")) {
        boolean exists = con.getMetaData().getTables(null, null, "PRODUCT", null).next();
        if (exists) {
            System.out.println("Table Exists");
        } else {
            String createDml = "CREATE TABLE PRODUCT (UPC VARCHAR(25), SHORT_DETAILS VARCHAR(50), LONG_DETAILS VARCHAR(5000), PRICE DECIMAL(10,2), STOCK INTEGER, PRIMARY KEY (UPC))";
            PreparedStatement createStatement =     con.prepareStatement(createDml);
            createStatement.execute();
        }
    } catch (SQLException e) {
        System.out.println("Can Not Connect At This Time");
    }
}

"what else i need to do" - how about describing the problem? — user253751, May 08 '17 at 05:53
Did compiler say 'package doesn't exist' or you got wrong result from query? — Fady Saad, May 08 '17 at 05:57
Remove `import javax.jms.Connection;` and use `import java.sql.Connection;` instead — Atul Dwivedi, May 08 '17 at 05:59
it is part of a fairly large project, there are many errors as of right now. in netbeans it says "cannot find symbol" and is underlined in red. i just want to focus on this part and get this class working. — Spectre6, May 08 '17 at 06:00

score 1 · Answer 1 · answered May 08 '17 at 05:58

1

You need to add the following imports

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

instead of the one you are using

answered May 08 '17 at 05:58

anthoon

101
9

score 1 · Answer 2 · answered May 08 '17 at 05:59

I'd suggest that you remove these lines:

import javax.jms.Connection;
import javax.jms.JMSException;

...as it's probably not the Connection class that you actually intended on importing. Your java.sql.* import should grab the correct one once you remove the lines above.

score 1 · Accepted Answer · edited Aug 16 '17 at 09:47

The problem is with imports. You imported javax.jms.Connection which is obiously wrong. Just delete it. What you wanted is Connection class from java.sql (java.sql.Connection) package.

Also I do not suggest to use wildcards (.*) in import but pick specific class you actually use. In your case:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

score 0 · Answer 4 · answered May 08 '17 at 07:28

Some of your imports are wrong. You need below to make it work.

  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.PreparedStatement;
  import java.sql.Connection;

One step ahead I would like to suggest you to have a separate class to establish the database connection. This way you don't need to repeat the same code again.

Sample code. (Do changes for this as appropriate.)

for instance have a DatabaseCon.java class in your project

  package classes;

  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.PreparedStatement;

  public class DatabaseCon {

      private static Connection c;

      private static void connect()
             throws Exception {
          Class.forName("com.mysql.jdbc.Driver").newInstance();
          String url = "db_url/db";
          c = DriverManager.getConnection(url, "username", "pass");
      }

      public static PreparedStatement prepareState(String sql)
           throws Exception {

          if (c == null) {
              connect();
          }
          return c.prepareStatement(sql);
      }

   }

This can then be called by

  public void yourMethod() {
      PreparedStatement p = null;
      try {
           p = DatabaseCon.prepareState("Your_query");
           ............

      } catch (Exception e) {
          //catch it
      } finally {
          //do the final stuff
      }
 }

Note This way is good if it is a fairly big project as you've mentioned.

score 0 · Answer 5 · edited May 23 '17 at 12:34

You have imported a few wrong classes for use.

import java.sql.DriverManager;
import javax.jms.Connection;
import java.sql.*;
import javax.jms.JMSException;

The jms imports are of no use; you have imported them in vain, which is causing issues in your program.

The main import required is java.sql.*, the application will work correctly if you just remove the jms imports.

But, the best practice to import classes is to specify the specific class from which you are using the element/method.

See here for the reason Single import vs package import

java.sql import not working

5 Answers5

Linked