//1加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2.创建连接
String url="jdbc:oracle:thin:@dulocalhost:1521:orcl"; //orcl为数据库的SID
String user="test";
String password="test";
Connection conn= DriverManager.getConnection(url,user,password);
//3.创建执行语句
PreparedStatement ps = con.prepareStatement("select * from user")
PreparedStatement ps = ps.executeQuery()；
//4.遍历结果集
while (rs.next()) {
 　　System.out.println(rs.getString("id") + " " + rs.getString("name"); 
} 
//5.关闭连接
ps.close();
conn.close();

//1加载驱动
Class.forName("com.mysql.jdbc.Driver");
//2.创建连接
String url="jdbc:mysql://localhost:3306/jdbc";
String user="root";
String password="123456";
Connection conn= DriverManager.getConnection(url,user,password);
//3.创建执行语句
PreparedStatement ps = con.prepareStatement("select * from user")
PreparedStatement ps = ps.executeQuery()；
//4.遍历结果集
while (rs.next()) {
 　　System.out.println(rs.getString("id") + " " + rs.getString("name"); 
} 
//5.关闭连接
ps.close();
conn.close();