windows - idea提示错误：java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

Question

碰见了一个问题，一直无法解决，希望大家帮帮忙。
这是连接mysql的JdbcUtils代码：

public class JdbcUtils {
    // 配置文件
    private static Properties props = null;
    // 静态块保证只加载一次
    static {
        InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream(
                "dbconfig.properties");
        props = new Properties();
        try {
            props.load(in);
        } catch (IOException e) {
            System.out.println("加载配置文件失败！");
            throw new RuntimeException(e);
        }

        try {
            Class.forName(props.getProperty("driverClassName"));
        } catch (ClassNotFoundException e) {
            System.out.println("驱动类加载失败");
            throw new RuntimeException(e);
        }
    }

    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(props.getProperty("url"),
                props.getProperty("username"), props.getProperty("password"));
    }
}

用下面的这个测试类证明jdbcutilis没有问题，可以加载com.mysql.jdbc.Driver

public class TestJDBCUserDao {
    @Test
    public  void test (){
        UserDao ud = UserDaoFactory.getUserDao("mysql");
        User user = new User();
        user = ud.findByName("111");
        System.out.println(user.getPassword());
    }
}

UserDao的jindByName是为了获得数据库连接：

项目也已经引入数据库驱动包，如图：

但当用tomcat跑时提示错误：
错误提示，驱动类加载失败,也就是：java.lang.ClassNotFoundException: com.mysql.jdbc.Driver，如图：

Answer 1

If you copy the jar package directly, right-click the jar and click add library. If it is a jsp project, you need to copy it to lib under web.

Answer 2

Put the jar package into the lib directory of tomcat at the same time