关于log4j的有关问题

public class Test {    private static Logger logger = Logger.getLogger(Test.class.getName());    public static void main(String[] args){                Connection conn = null;            try {                Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");            } catch (ClassNotFoundException e) {                logger.error(e);            }            try{                conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName = Stu", "sa", "123");                System.out.println("建立连接成功");            }catch(SQLException e){                logger.error(e);            }finally{                try{                    if(null!=conn){                        conn.close();                        System.out.println("关闭连接成功");                    }                }catch(SQLException e){                    logger.error(e);                }            }    }}