获取“ java.sql.SQLException：Io异常：网络适配器无法建立连接”

Question

The below is my code. I wanted to connect to Employee table from Oracle.

public static void main(String[] args) {         
    try {
        DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
        Connection connection = DriverManager.getConnection(
                    "jdbc:oracle:thin:@localhost:1521:orcl", "scott", "tiger");
        Statement statement = connection.createStatement();
        ResultSet resultset = statement.executeQuery("select 'Connected' from dual");
        resultset.next();
        String s = resultset.getString(1);
        System.out.println(s);
        statement.close();
        connection.close();
    } catch (Exception e) {
        System.out.println("The exception raised is:" + e);
    }
}

I am always getting the error as "The exception raised is:java.sql.SQLException: Io exception: The Network Adapter could not establish the connection"

I tried turning off the firewall, but no luck. Could someone please help me in resolving the issue.

Answer 1

Did you try telnet'ing that db? something like...

Telnet localhost 1521

Just to check if there is a process listing to that port.

Answer 2

It can be three thins:

1. The Database is not running or doesn't exist
2. The URL you have is invalid
3. The Database is running in different Port.
4. You have a firewall( In this case can't be because you already check that)

Ok, when My team was in a black box server with an url for connecting to the Database we didn't know what was the error and so we created a UDL File that can make this test. Check this tutorial for connection testing With that you can test the three of them and see if you have a real connection with the Database.