import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class Application {public static Connection getConnection() {Connection conn = null;try {			//连接driver为：oracle.jdbc.driver.OracleDriver//或者oracle.jdbc.OracleDriver，前者extends后者Class.forName("oracle.jdbc.OracleDriver");String url="jdbc:oracle:thin:@localhost:1521:orcl";String user="scott";String password="wjk139";try {//建立连接conn = DriverManager.getConnection(url,user,password);System.out.println("返回的conn值："+conn);//用于在控制台输出返回的信息return conn;} catch (SQLException e) {e.printStackTrace();}} catch (ClassNotFoundException e) {e.printStackTrace();} finally {if (conn != null) {try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}return null;}public static void main(String[] args) {Connection conn = getConnection();if (conn != null) {System.out.println("连接成功");System.out.println("返回的值："+conn);} else {System.out.println("连接失败");System.out.println("返回的值："+conn);}}
}

如果访问成功，则会返回一串字符串，若不成功，则不会返回值
下面是连接成功与失败时的控制台界面

图1 连接成功的界面

图2 连接失败时的界面

以上就是对Oracle数据库成功与否的判断