[JDBC] error exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.communicationsexception: communica

SQL No problem with the writing ,JDBC Of jar The package is also imported normally , The following error is reported during operation because the database version is different from jar Package version is inconsistent

It used to be 5.1.47 Version of jar package , And the database is MySQL8.0.11 The version difference is too large to drive the connection

Import the new version jar After the package is added to the library, you can connect to the database normally

After successfully connecting to the database, some people may appear such a warning

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

translate ： Loading class com.mysql.jdbc. The driver '. This is not recommended . The new driver class is com.mysql.cj.jdbc. The driver . The driver passes SPI Automatic registration , There is usually no need to manually load driver classes .

Don't worry. ！ I'll teach you how to solve it

First of all, this is a warning , It has no impact on the operation of the program You can see that the exit code is 0, This indicates that the program was successfully executed , But some friends have OCD and don't want to see what to do every time they run ？

Then just press the prompt to update the driver

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

Connection template ：

public static void main(String[] args) throws SQLException, ClassNotFoundException {
        //1. Registration drive 
        Driver driver = new Driver();

        //2. Get links 
        String url = "jdbc:mysql://localhost:3306/pyq";
        // Put the user name and password into Properties object 
        Properties properties=new Properties();
        properties.setProperty("user","root");
        properties.setProperty("password","284650"); // Your own password 
        Connection connect = driver.connect(url, properties);

        //3. perform SQL
        String sql="insert into actor values(null,' peng ',' male ','2000-5-20','220')";
        Statement statement = connect.createStatement();
        int rows = statement.executeUpdate(sql);
 
        //4. Close the connection 
        statement.close();
        connect.close();
    }