MySQL封装工具类

将连接数据库的方法进行封装，并在别的类中进行使用，并且要声明静态方法，

 //1.获取连接
    public static Connection getConnection()
    {
        Connection connection = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/shujuku?&useUnicode=true&serverTimezone=UTC";
            String user = "root";
            String password = "123456";
            connection = DriverManager.getConnection(url,user,password);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return connection;
    }

注意返回值为Connection类型名称为getConnection

将关闭方法进行封装，同样声明成为静态方法

方法名称为closeAll，传入三个参数，为防止空指针异常，需要用if语句判断。

    public static void closeall(Connection connection, Statement statement, ResultSet resultSet)
    {
        try {
            if(resultSet != null)
                resultSet.close();
            if(statement != null)
                statement.close();
            if(connection != null)
                connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }

//最终版本
public class JDutil {
    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    //1.获取连接
    public static Connection getConnection()
    {
        Connection connection = null;
        try {
            String url = "jdbc:mysql://localhost:3306/shujuku";
            String user = "root";
            String password = "123456";
            connection = DriverManager.getConnection(url,user,password);
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        return connection;
    }
    public static void closeAll(Connection connection, Statement statement, ResultSet resultSet)
    {
        try {
            if(resultSet != null)
                resultSet.close();
            if(statement != null)
                statement.close();
            if(connection != null)
                connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

}