Can't print out the contents of mysql database

Question

Basically everything's connected and database works properly except for the fact that I'm unable to print anything out of it into the console. And I dunno how 2 fix this very problem. Help me out pls

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.*;

class Main{
    private static final String url = "jdbc:mysql://localhost:3306/";
    private static final String user = "root";
    private static final String password = "12345678";
    public static void main(String args[]){
        try {
            Class.forName("com.mysql.jdbc.Driver");//it goes to catch immediately after this line
            Connection con = DriverManager.getConnection(url, user, password);
            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery("select * from emp");
            while (rs.next()) {
                int price = rs.getInt(3);
                System.out.println(price);
            }
            con.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }

    }
}

That what it prints in the end of execution:

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

Process finished with exit code 0

It definitely contains data. The problem is in the 1 line of the main method I suppose — Matthew, Dec 11 '20 at 19:50
_"it goes to catch immediately after this line"_ - and prints an error message and stack trace, I assume. You can [edit] your question to show this (formatted) information. Also, there are many questions on SO about JDBC URLs + MySQL + `Class.forName()` + driver JAR file locations + classpath issues. Have you researched those? — andrewJames, Dec 11 '20 at 20:02
I went through a bunch of pages about that but I guess I missed something — Matthew, Dec 11 '20 at 20:05
Two pointers: (1) Using `Class.forName()` is [no longer required](https://stackoverflow.com/questions/5484227/jdbc-class-forname-vs-drivermanager-registerdriver) in most situations involving modern JDBC drivers. (2) You may still get `ClassNotFoundException` even after removing that line of code. See [here](https://stackoverflow.com/questions/2839321/connect-java-to-a-mysql-database/2840358#2840358). — andrewJames, Dec 11 '20 at 20:54

score 1 · Answer 1 · answered Dec 11 '20 at 19:54

1

You should name your database when connecting to MySQL:

private static final String url = "jdbc:mysql://localhost:3306/your_database_name";

answered Dec 11 '20 at 19:54

jmizv

1,172
2
11
28

hasn't helped :( – Matthew Dec 11 '20 at 19:59
2

It may not have helped immediately, because this problem is hiding behind other errors, but it is a necessary fix – andrewJames Dec 11 '20 at 22:28

Marshall C · Answer 2 · 2020-12-11T20:25:38.980

1

It appears you have an off-by-one issue. Column 3 is the "Manufacturer" (a string). According to the docs "the first column is 1, the second is 2, ..."

https://docs.oracle.com/javase/7/docs/api/java/sql/ResultSet.html#getInt(int)

rs.getString(3);
rs.getInt(4);
rs.getInt("ProductCount");

I just noticed you added the error message. It appears you need to add the mysql connector jar. See if this post answers your question :

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver in Eclipse

edited Dec 11 '20 at 20:25

answered Dec 11 '20 at 20:12

Marshall C

359
3
8

You r right, mate but the compiler doesn't even get to execute that part of me code. Cos smth is wrong with the first line of Main – Matthew Dec 11 '20 at 20:15

Can't print out the contents of mysql database

2 Answers2