Question

package connection;


import java.sql.*;
public class Connection {


    public static void main(String[] args) throws Exception
    {
        Connection con1=null;
        String c="oracle.jdbc.driver.OracleDriver";
        Class.forName(c);
        String url="jdbc:oracle:thin:@LAPTOP-1CQ5FAGB:1521:XE";
        String user="system";
        String passwd="srpnk";
                 con1=(Connection) DriverManager.getConnection("jdbc:oracle:thin:@LAPTOP-1CQ5FAGB:1521:XE","system","srpnk");
        System.out.println("connected");        
    }

}

错误

Exception in thread "main" java.lang.ClassCastException: oracle.jdbc.driver.T4CConnection cannot be cast to connection.Connection
    at connection.Connection.main(Connection.java:17)
C:\Users\Nandhini\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 0 seconds)

Answer 1

重命名您的班级public class Connection，它与java.sql.Connection ...

发生冲突

public class Connection { // <-- This is a bad idea

    public static void main(String[] args) throws Exception
    {
        Connection con1=null;
        // ...
        con1=(Connection) DriverManager.getConnection("jdbc:oracle:thin:@LAPTOP-1CQ5FAGB:1521:XE","system","srpnk");
        System.out.println("connected");        
    }

需要设置DriverManager.getConnection的结果应该有一组警钟

（是的，从技术上讲，你可以使用java.sql.Connection con1...这个仍然是一个坏主意，并且可能继续导致问题没有结束）

我无法在运行时连接到数据库

1 个答案: