mongodb薄封装下，能自定义_id么

实例
zMoCo.save(ZMoDoc.NEW("_id","555"));
想要达到目的是设置文档的_id:555
运行后报错 “555”不是ObjectId，

java.lang.RuntimeException: '555' not ObjectId
at org.nutz.lang.Lang.makeThrow(Lang.java:132)
at org.nutz.mongo.ZMoDoc.put(ZMoDoc.java:492)
at org.nutz.mongo.ZMoDoc.putv(ZMoDoc.java:125)
at org.nutz.mongo.ZMoDoc.NEW(ZMoDoc.java:46)
at com.tianshi.timer.MongodbTest.insert(MongodbTest.java:32)
at com.tianshi.timer.MongodbTest$$FASTCLASS._invoke(MongodbTest.java:1)
at org.nutz.lang.reflect.AbstractFastClass.invoke(AbstractFastClass.java:143)
at org.nutz.lang.reflect.FastClassFactory.invoke(FastClassFactory.java:67)
at org.nutz.mvc.impl.processor.MethodInvokeProcessor.process(MethodInvokeProcessor.java:27)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.AdaptorProcessor.process(AdaptorProcessor.java:33)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.ActionFiltersProcessor.process(ActionFiltersProcessor.java:58)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.ModuleProcessor.process(ModuleProcessor.java:123)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.EncodingProcessor.process(EncodingProcessor.java:27)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.UpdateRequestAttributesProcessor.process(UpdateRequestAttributesProcessor.java:15)
at org.nutz.mvc.impl.NutActionChain.doChain(NutActionChain.java:44)
at org.nutz.mvc.impl.ActionInvoker.invoke(ActionInvoker.java:67)
at org.nutz.mvc.ActionHandler.handle(ActionHandler.java:31)
at org.nutz.mvc.NutFilter.doFilter(NutFilter.java:198)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:509)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1104)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)