这个jndi连接数据源的问题怎么解决？

请问一下我连接数据源是jndi name为lyj,它与连接池相连，下面是一段获取数据源的代码为什么会出错，
properties.get("DBFullJndiContext")的值为：java:comp/env/jdbc/lyj

try {
InitialContext initCtx = new InitialContext();
if (properties.containsKey("DBFullJndiContext")) {
dataSource = (DataSource) initCtx.lookup((String) properties.get("DBFullJndiContext"));
} else {
Context ctx = (Context) initCtx.lookup((String) properties.get("DBInitialContext"));
dataSource = (DataSource) ctx.lookup((String) properties.get("DBLookup"));
}
} catch (NamingException e) {
throw new SqlMapException("There was an error configuring JndiDataSourceDaoTransactionPool. Cause: " + e, e);
}
}