Question

dom解析xml疑问

<?xml version="1.0" encoding="UTF-8"?>
<publication>
<book>
<title>the mythical man-month</title>
<writer>frederick p.brooks Jr.</writer>
<publishdate>1975-03-12</publishdate>
</book>
<book>
<title>think in java</title>
<writer>bruce eckel</writer>
<publishdate>1999-11-01</publishdate>
</book>
</publication>

代码如下
public class useDomPrintElement {
public static void main(String[] args){
try{
//获得一个XML文件的解析器
DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
//解析XML文件生成DOM文档的接口类，以便访问DOM
DocumentBuilder builder=factory.newDocumentBuilder();
//Document接口描述了对应于整个XML文件的文档树
Document document=builder.parse(new File("publication.xml"));
//获得根元素的子节点列表
Element element=document.getDocumentElement();
NodeList nodelist=element.getChildNodes();
//如果预知根元素的名称，也可以使用下边的方法获取根元素的子节点列表
//NodeList nodelist=document.getElementsByTagName("publication");
//用递归方法实现DOM文档的遍历
GetElement(nodelist);
}catch(Exception e){
e.printStackTrace();
}
}
public static void GetElement (NodeList nodelist){
Node cnode;
String str;
if(nodelist.getLength()==0){
//该节点没有子节点
return;
}
for(int i=0;i<nodelist.getLength();i++){
cnode=nodelist.item(i);
System.out.println("nodelist:"+nodelist);
//System.out.println("getlength:"+nodelist.getLength());

if(cnode.getNodeType()==Node.ELEMENT_NODE){
//打印节点名称
//System.out.println(cnode.getNodeName()+":");
//递归调用GetElement
GetElement(cnode.getChildNodes());
}
else if(cnode.getNodeType()==Node.TEXT_NODE){
str=cnode.getNodeValue().trim();
//当该对象不为空时显示信息
//if(str.length()>0)
// System.out.println(" "+str);

}
}
}
}
打印结果
nodelist:[publication: null]
nodelist:[publication: null]
nodelist:[book: null]
nodelist:[book: null]
nodelist:[title: null]
nodelist:[book: null]
nodelist:[book: null]
nodelist:[writer: null]
nodelist:[book: null]
nodelist:[book: null]
nodelist:[publishdate: null]
nodelist:[book: null]
nodelist:[publication: null]
nodelist:[publication: null]
nodelist:[book: null]
nodelist:[book: null]
nodelist:[title: null]
nodelist:[book: null]
nodelist:[book: null]
nodelist:[writer: null]
nodelist:[book: null]
nodelist:[book: null]
nodelist:[publishdate: null]
nodelist:[book: null]
nodelist:[publication: null]

打印的结果不明白，还有nodelist长度是怎么算的

Answer 1

DOM方式访问XML，在xml文件中的回车换行符，Dom会认为是一个纯文本
你可将xml文档中的所有换行去掉，看一下结果，你就明白了
如：
<?xml version="1.0" encoding="UTF-8"?><publication><book><title>the mythical man-month</title><writer>frederick p.brooks Jr.</writer>
<publishdate>1975-03-12</publishdate></book><book><title>think in java</title><writer>bruce eckel</writer><publishdate>1999-11-01</publishdate></book></publication>
看看结果