code: public static DataSource getJndiDs(String jndiName) {
  		try {
  			return (DataSource) new InitialContext().lookup(jndiName);
  		} catch (NamingException e) {
  			throw new DbRuntimeException(e);
  		}
  	}
docs: 获得JNDI数据源
  
  @param jndiName JNDI名称
  @return 数据源