How to connect JDBC to tns oracle

问题:

I can connect from plsql to database using tns file

Now I want to connect to the database from my Java using JDBC.

What I tried:

I search google and I find that I have to using this connection String:

"jdbc:oracle:thin:@//host:port))/tnsfile)";

My computer name is myPC

The port that is written in the tnsfile is 5151

So I tried this connection String

"jdbc:oracle:thin:@//myPC:5151))/tnsfile"

but I got this Exception

java.sql.SQLRecoverableException: IO ERROR: SO Exception was generated

What am I doing wrong?

How to connect my JDBC to the database using tns file?

回答1:

You have to set a property named oracle.net.tns_admin to point to the location of the folder containing your tnsnames.ora file. Then you specify the entry from that file after the @ sign in your DB URL. Check example below. You can find more information here: Data sources and URLs - Oracle Documentation

import java.sql.*;

public class Main {
  public static void main(String[] args) throws Exception {
    System.setProperty("oracle.net.tns_admin", "C:/app/product/11.2.0/client_1/NETWORK/ADMIN");
    String dbURL = "jdbc:oracle:thin:@ENTRY_FROM_TNSNAMES";

    Class.forName ("oracle.jdbc.OracleDriver");

    Connection conn = null;
    Statement stmt = null;

    try {
      conn = DriverManager.getConnection(dbURL, "your_user_name", "your_password");

      System.out.println("Connection established");

      stmt = conn.createStatement();

      ResultSet rs = stmt.executeQuery("SELECT dummy FROM dual");

      if (rs.next()) {
        System.out.println(rs.getString(1));
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    finally {
      if (stmt != null) try { stmt.close(); } catch (Exception e) {}
      if (conn != null) try { conn.close(); } catch (Exception e) {}
    }
  }
}

Example entry from tnsnames.ora file:

my_net_service_name= 
 (DESCRIPTION= 
   (ADDRESS=(some address here))
   (CONNECT_DATA= 
     (SID=some_SID_name)))

Where my_net_service_name string is what you have to subsitite for ENTRY_FROM_TNSNAMES from my Java example.

回答2:

Rather than hard code the path to tnsnames.ora, better to find it from the environment:

public static void setTnsAdmin() {
    String tnsAdmin = System.getenv("TNS_ADMIN");
    if (tnsAdmin == null) {
        String oracleHome = System.getenv("ORACLE_HOME");
        if (oracleHome == null) {
            return; //failed to find any useful env variables
        }
        tnsAdmin = oracleHome + File.separatorChar + "network" + File.separatorChar + "admin";
    }
    System.setProperty("oracle.net.tns_admin", tnsAdmin);
}

回答3:

Try the following:

System.setProperty("oracle.net.tns_admin", PATH_TO_TNSNAMES.ORA);
Class.forName ("oracle.jdbc.OracleDriver");
dbUrl = "jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST="+IPHOST+")(PORT="+PORT+"))(CONNECT_DATA=(SERVER = DEDICATED)(SERVICE_NAME="+DBNAME+")))"

conn = DriverManager.getConnection(dbUrl, USERNAME, PASSWORD);

Be sure to have the latest version of ojdbc.jar