How to test if JDBC driver is installed correctly

问题:

I tried installing this at home along with Java SDK... The SDK worked fine and I can now use the command prompt to compile java programs into classes...

However I am unsure how to test if JDBC is working to connect to my server/databases/mysql.

As I have a feeling my server (Which is a shared website/webhost) may not allow the connection...

How can I test that the JDBC was installed correctly without having to connect to a server?

And then how can I test (Seperate code please) that the (now confirmed working) JDBC is connecting to my databases?

Thanks alot.

回答1:

How can I test that the JDBC was installed correctly without having to connect to a server?

Just check if Class#forName() on the JDBC driver doesn't throw ClassNotFoundException.

try {
    Class.forName(driverClassName);
    // Success.
}
catch (ClassNotFoundException e) {
    // Fail.
}

---

And then how can I test (Seperate code please) that the (now confirmed working) JDBC is connecting to my databases?

Just check if DriverManager#getConnection() or DataSource#getConnection() doesn't throw SQLException.

try (Connection connection = DriverManager.getConnection(url, username, password)) {
    // Success.
}
catch (SQLException e) {
    // Fail.
}

See also

• Exceptions tutorial
• JDBC+MySQL mini tutorial

回答2:

First, download MySQL's JDBC driver and put it somewhere in your application's classpath.

Second, try to register that driver in your Java code, using

Class.forName("com.mysql.jdbc.Driver");

If that doesn't throw an exception, you've managed to register sucessfully.

Third, check if your connection works:

Connection conn =  DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql","user", "pass");

Substitute your URL, username and password as needed.

回答3:

Install a database locally and connect to that.

You can check the connection to the server by using telnet to connect to the port where the database should be listening; if you can open a connection, you know there isn't a network problem (such as a firewall). If JDBC is okay and the network is okay, then you can try connecting to the remote system. If that doesn't work, it's some kind of configuration problem.