jdbc连接数据库连不上

导包 ojdbc6.jar
jdk 1.7.0_0.09
oracle版本
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

//jdbc类
public class jdbc {

public static void main(String[]args){
    Connection conn=null;
    Statement state=null;
    try {
        Class.forName("oracle.jdbc.OracleDriver");
    } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        System.out.println("11");
    }

    try {
        conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","QMXC_PROJECT","qmxc");
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        System.out.println("22");
    }

    try {
        state=conn.createStatement();
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        System.out.println("33");
    }

    try {
        state.execute("insert into wen values (1,'wen','12','nan'");
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        System.out.println("sql语句错误");
    }
}

}

//报错
java.sql.SQLException: Undefined Error
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:412)
at oracle.jdbc.driver.PhysicalConnection.(PhysicalConnection.java:531)
at oracle.jdbc.driver.T4CConnection.(T4CConnection.java:221)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:503)
at java.sql.DriverManager.getConnection(DriverManager.java:579)
at java.sql.DriverManager.getConnection(DriverManager.java:221)
at jdbc.main(jdbc.java:21)
Caused by: oracle.net.ns.NetException: Undefined Error
at oracle.net.ns.NSProtocol.connect(NSProtocol.java:385)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1042)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:301)
... 7 more

报错是网络错误，看下防火墙是否允许了oracle的端口，还有ip地址对不对，还有服务器是否正常运行

换ojdbc jar

见：
https://blog.csdn.net/Zheng548/article/details/51804463