com.microsoft.sqlserver.jdbc.SQLServerDriver的ClassNotFoundException

Question

This is an issue that has come up before on SO, and I'm sure seasoned Java devs are tired of telling newbies howto set the classpath. That said, I've tried setting the classpath via environment variable and with the -cp option, with no success.

I'm using the sample applications that are bundled with the SQLServer JDBC driver. I'm running Ubuntu 14.10. I compile the app on the command line:

javac -cp .:/path/to/sqljdbc42.jar connectURL.java 

and the run it:

java connectURL

which gets me the familiar ClassNotFoundException :

java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:191)
    at connectURL.main(connectURL.java:42)

I haven't modified the sample class file, but I'm including it here for completeness:

import java.sql.*;

public class connectURL {

    public static void main(String[] args) {

        // Create a variable for the connection string.
        String connectionUrl = "jdbc:sqlserver://localhost:1433;" +
            "databaseName=AdventureWorks;integratedSecurity=true;";

        // Declare the JDBC objects.
        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;

            try {
                // Establish the connection.
                Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
                    con = DriverManager.getConnection(connectionUrl);

                    // Create and execute an SQL statement that returns some data.
                    String SQL = "SELECT TOP 10 * FROM Person.Contact";
                    stmt = con.createStatement();
                    rs = stmt.executeQuery(SQL);

                    // Iterate through the data in the result set and display it.
                    while (rs.next()) {
                        System.out.println(rs.getString(4) + " " + rs.getString(6));
                    }
            }

        // Handle any errors that may have occurred.
        catch (Exception e) {
            e.printStackTrace();
        }

        finally {
            if (rs != null) try { rs.close(); } catch(Exception e) {}
                if (stmt != null) try { stmt.close(); } catch(Exception e) {}
                if (con != null) try { con.close(); } catch(Exception e) {}
        }
    }
}

The path to the SQL JDBC .jar is definitely correct. If I add import com.microsoft.sqlserver.jdbc.SQLServerDriver; to the class file I don't get any complaints when compiling, but still get the ClassNotFoundException at runtime.

I've read elsewhere that newer versions of the JDBC don't need you to load drivers via Class.forName , but if I remove that line then I get, predictably, java.sql.SQLException: No suitable driver found .

What am I doing wrong? I'm sure the .jar is being loaded and the class is being found, because if I try eg import com.microsoft.sqlserver.jdbc.SomeNonExistentClass; I get:

connectURL.java:2: error: cannot find symbol

My Java details:

$ java -version
java version "1.7.0_79"
OpenJDK Runtime Environment (IcedTea 2.5.5) (7u79-2.5.5-0ubuntu0.14.10.2)
OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)

Answer 1

You're halfway there. You include the JDBC JAR on your classpath when you compile, but you also need to include it on your classpath when you execute it as well:

java -cp .:/path/to/sqljdbc42.jar connectURL