Initialcontext in a standalone Java program

Question

I\'m using a JNDI for creating tomcat connection pool. It works great in a web application. I believe the InitialContext is provided by the tomcat server.

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Answer 1

You can create your own Context by sub-classing javax.naming.InitialContext and implementing only a small subset of methods, typically the bind and the lookup methods.

Then you can create your data source and bind it to your initial context to a specific key. After this you are ready to go and query from any place your JNDI context in your stand-alone Java programme.

This is the code you can use to create your own context:

InitialContext initialContext = new InitialContext() {

    private Map table = new HashMap<>();

    public void bind(String key, Object value) {
        table.put(key, value);
    }

    public Object lookup(String key) throws NamingException {
        return table.get(key);
    }
};

// Activate the initial context
NamingManager.setInitialContextFactoryBuilder(environment -> environment1 -> initialContext);

Then you can initialise your data source, whichever you choose:

InitialContext ic = new InitialContext();

BasicDataSource bds = new BasicDataSource();
bds.setDriverClassName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
bds.setUrl(url);
bds.setUsername(username);
bds.setPassword(password);

ic.bind(jndiPath, bds);

And somewhere else in your code, you can use the existing data source by retrieving it from the JNDI context:

InitialContext ic2 = new InitialContext();
DataSource ds = (DataSource) ic2.lookup(jndiPath);
assertNotNull(ds);
Connection conn = ds.getConnection();
assertNotNull(conn);
conn.close();