Or maybe? 1) Connecting to Oracle 8i w / ojdbc5 or ojdbc6 2) Many ojdbc containers

Question

I am creating an application that collects data from several data sources. From these data sources, we have several instances of Oracle.

I found that the only way to connect to my Oracle 8i instance is to use ojdbc14.jar and the following:

String driver = "oracle.jdbc.OracleDriver"; String url = "jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=$HOST)(PORT=$PORT)))(CONNECT_DATA=(SID=$SID)))" Class.forName(driver); Connection c = DriverManager.getConnection(url, $USER, $PASSWORD); c.close(); 

When I try to update ojdbc5.jar or ojdbc6.jar using the same code, I get an ArrayIndexOutofBoundsException. The same thing if I only use the url "jdbc: oracle: thin: $ user / $ password @ $ host: $ port: $ sid", which works against more recent Oracle instances that I connect with.

I would prefer not to focus on using the older ojdbc14.jar (especially since I use Java 6), as I may have to support higher Oracle databases in the future.

So, I hope that one of two scenarios is possible:

1) There, the connection string, which I simply ignore, can be used to connect to Oracle 8i with newer OJDBC banks.

2) I can have several OJDBC tanks in my class path so that I can use ojdbc14.jar in the exception database and ojdbc6.jar everywhere. The trick here, of course, is how to determine which jar connection to use for the class "oracle.jdbc.OracleDriver".

Any thoughts?

Answer 1

Just out of curiosity, I implemented your second approach through an isolated class loader. It seems to work:

 public class DriverWrapper implements Driver { private Driver target; private String fakePrefix; private String realPrefix; protected DriverWrapper(Driver target, String fakePrefix, String realPrefix) { this.target = target; this.fakePrefix = fakePrefix; this.realPrefix = realPrefix; } public static void loadDriver(URL[] classPath, String className, String fakePrefix, String actualPrefix) throws Exception{ URLClassLoader cl = new URLClassLoader(classPath, DriverWrapper.class.getClassLoader()); Class<?> c = cl.loadClass(className); // It rather rude, but we haven't access to the existing instance anyway Driver d = (Driver) c.newInstance(); Driver w = new DriverWrapper(d, fakePrefix, actualPrefix); // We don't care about already registerd instance, // because driver loaded in isolated classloader // is not visible to the rest of application, see DriverManager javadoc DriverManager.registerDriver(w); } private String resolveURL(String url) { if (url.startsWith(fakePrefix)) { return realPrefix + url.substring(fakePrefix.length()); } else { return null; } } public boolean acceptsURL(String url) throws SQLException { url = resolveURL(url); if (url == null) { return false; } else { return target.acceptsURL(url); } } public Connection connect(String url, Properties info) throws SQLException { url = resolveURL(url); if (url == null) { return null; } else { return target.connect(url, info); } } public int getMajorVersion() { return target.getMajorVersion(); } public int getMinorVersion() { return target.getMinorVersion(); } public DriverPropertyInfo[] getPropertyInfo(String url, Properties info) throws SQLException { return target.getPropertyInfo(url, info); } public boolean jdbcCompliant() { return target.jdbcCompliant(); } } 

Used as follows (driver banks should not be in the main path):

 DriverWrapper.loadDriver(new URL[] { new File("ojdbc5.jar").toURL() }, "oracle.jdbc.OracleDriver", "jdbc:oracle5", "jdbc:oracle"); DriverWrapper.loadDriver(new URL[] { new File("ojdbc14.jar").toURL() }, "oracle.jdbc.OracleDriver", "jdbc:oracle14", "jdbc:oracle"); ... DriverManager.getConnection("jdbc:oracle14:...", ...); ... DriverManager.getConnection("jdbc:oracle5:...", ...);