你好，我试图连接到Oracle 11g数据库使用ojdbc14 jar在eclipseKepler与java 8在windows 7操作系统。但当我运行的代码，我得到以下错误。这里是我的错误相应。

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Scanner;

    public class JDBCExample {
      public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       System.out.println("enter your databse details");
       System.out.println("user name");
       String uName = sc.next();
       System.out.println("password");
       String pWord = sc.next();
       try {
          Class.forName("oracle.jdbc.driver.OracleDriver");
       } catch (ClassNotFoundException e) {
        e.printStackTrace();
       }
       Connection conn = null;
       try {
        conn = DriverManager.getConnection(
                "jdbc:oracle:thin:@localhost:1521:orcl", "scott", "tiger");
        // jdbc:oracle:thin:@server:1521:xe
       } catch (SQLException e) {
        e.printStackTrace();
       }
       if (conn != null) {
        System.out.println("Successfully connected to DB");
        } else {
        System.out.println("Failed to connect to DB");
       }
   }
}

错误如下。java.sql.SQLException: Io exception: The Network Adapter could not establish the connection at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146) at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:255) at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387) at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:414) at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:165) at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35) at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:801) at java.sql.DriverManager.getConnection(Unknown Source) at java.sql.DriverManager.getConnection(Unknown Source) at JDBCExample.main(JDBCExample.java:23)