我想创建一个简单的xml节点，我查看了来自http://docs.groovy-lang.org/latest/html/api/groovy/util/Node.html的文档并编写这些代码。defnewbook=newNode(null,'book',[id:'3'])newbook.appendNode(newNode(newbook,'title',[id:'BookId3']))newbook.appendNode(newNode(newbook,'author',[id:'3'],'HarperLee'))printlngroovy.xml.XmlUtil.serializ