使用nutz 加载.properties 注入参数报错

conf : {
			type : "org.nutz.ioc.impl.PropertiesProxy",
			fields : {
				paths : ["ioc/sys.properties"]
			}
	},
	entityCode:{
		type:"java.lang.Integer",
		args : {java : '$conf.get("entityCode")'}
	},

报错日志截取：

Caused by: org.nutz.lang.born.BorningException: Fail to born 'java.lang.Integer'
by args: [
@($conf.get("entityCode"))] becasue:
java.lang.NumberFormatException: For input string: "$conf.get("entityCode")"
at org.nutz.lang.born.ConstructorBorning.born(ConstructorBorning.java:19)
at org.nutz.ioc.weaver.DefaultWeaver.born(DefaultWeaver.java:67)
at org.nutz.ioc.impl.ObjectMakerImpl.make(ObjectMakerImpl.java:103)
... 35 more
Caused by: java.lang.NumberFormatException: For input string: "$conf.get("entityCode")"

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