Cannot find the JDBC driver

0
votes

I have a simple JDBC code.

static Connection c;
static PreparedStatement ps;

public static void initializeDB() throws IOException, ClassNotFoundException, SQLException {
    Properties prop = new Properties();
    prop.load(new FileInputStream("dbconn.properties"));
    String connurl = prop.getProperty("connurl");
    String driver = prop.getProperty("driver");
    String username = prop.getProperty("username");
    String password = prop.getProperty("password");
    System.out.println(driver); //prints "com.mysql.jdbc.Driver"
    Class.forName(driver);
    c = DriverManager.getConnection(connurl, username, password);

  1. But I'm getting

    java.lang.ClassNotFoundException: "com.mysql.jdbc.Driver" at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:169) at testapp.DBUpdater.initializeDB(Testapp.java:71) at testapp.Testapp.main(Testapp.java:38)

The property values are perfectly accessed as seen from the print statement. When I replace the variables with the string values directly it works fine!!

  1. When should I use

    prop.load(new FileInputStream(System.getProperty("dbconn.properties")));

  2. When I viewed the Driver class from the mysql-connector jar file, I was expecting to see some static code but didn't find anything.

2
javajdbc
Hint: You no longer need Class.forName() with modern JDBC drivers, since JDBC can now use the the ServiceLoader system for finding drivers (more info here). You will still find the forName() call in many tutorials since it doesn't break anything. – Joachim Sauer
When printing out a string for test, place characters such as "><" on either side of the string to be sure there are no blanks hiding there. If you're getting the name printed "correctly", but the class is not found by forName, then the class is not found -- simple enough. Has nothing to do with properties. – Hot Licks
(And it should be pointed out that you're not using the result of Class.forName, and never creating an instance of it.) – Hot Licks
(What do you mean by "static code" in question 3?) – Hot Licks
Make sure your JDBC driver is in the classpath. – Jesper

2 Answers

1
votes

It looks like the string has value "com.mysql.jdbc.Driver" (note the double quotes) instead of com.mysql.jdbc.Driver.

Remove those quotes and it should work.

0
votes

  1. Try to trim the values of the properties.

  2. I would have load the properties in a static way.

  3. I didn't understand why you had a look within this JAR...

Example:

class Database {

    private final static Properties properties;
    private static Connection c;
    private static PreparedStatement ps;

    static {
        properties = new Properties();
        properties.load(new FileInputStream("dbconn.properties"));
    }

    public static void init() {
        String connurl = properties.getProperty("connurl").trim();
        String driver = properties.getProperty("driver").trim();
        String username = properties.getProperty("username").trim();
        String password = properties.getProperty("password").trim();
        Class.forName(driver);
        c = DriverManager.getConnection(connurl, username, password);
    }

}