<GlobalNamingResources>
    <Resource
        auth="Container"
        driverClassName="com.microsoft.sqlserver.jdbc.SQLServerDriver"
        logAbandoned="true"
        maxActive="20"
        maxIdle="10"
        maxWait="5000"
        name="jdbc/datasource1"
        removeAbandoned="true"
        removeAbandonedTimeout="60"
        type="javax.sql.DataSource"
        url="jdbc:sqlserver://localhost;databaseName=database1"
        username="username"
        password="password"/>
</GlobalNamingResources>

try {
    Context initCtx = new InitialContext();
    Context envCtx = (Context) initCtx.lookup("java:comp/env");
    DataSource ds = (DataSource) envCtx.lookup("datasource1");
    ds.getConnection(); // If this line doesn't throw SQLException, the db connection is established successfully
} catch(NamingException ex) {
    System.out.println("JNDI lookup failed: " + ex.getMessage());
} catch(SQLException se) {
    System.out.println("Unable to establish connection: " + se.getMessage());
}

<ResourceLink global="jdbc/datasource1" name="datasource1" type="javax.sql.DataSource"/>