JDBC规范化写法

@Test
public void fun3() throws SQLException
{
    Connection connection=null;
    Statement statement=null;
    ResultSet resultSet=null;
    try{
    String driverClassName="com.mysql.jdbc.Driver";

    String url="jdbc:mysql://localhost:3306/exam";

    String username="root";

    String password="123";

    Class.forName(driverClassName);

    connection=DriverManager.getConnection(url,username,password);
    /*
     * 创建statement
     */
    statement=connection.createStatement();

    String sqlString="select * from emp";

    resultSet=statement.executeQuery(sqlString);
    /*
     * 
     * 循环遍历rs ,打印其中数据
     */
    while(resultSet.next())
    {
        System.out.println(resultSet.getString(1)+","+resultSet.getString(2));
    }
    }catch(Exception e)
    {
        throw new RuntimeException(e);
    }
    finally{
        //关闭资源
        if(resultSet!=null) resultSet.close();
        if(statement!=null) statement.close();
        if(connection!=null) connection.close();
    }
}