Java:获取嵌套xml文件中的子节点值之和
我需要制作一个程序,输出xml文件中特定元素的价格。 xml文件如下所示:Java:获取嵌套xml文件中的子节点值之和,java,xml,dom,Java,Xml,Dom,我需要制作一个程序,输出xml文件中特定元素的价格。 xml文件如下所示: <list name="root"> <book name="B1" price="30" isbn="123"/> <list name="L1"> <book name="B2" price="20" isbn="234"/> <list name="L2"> <cd name="C1" price="15"/> <cd nam
<list name="root">
<book name="B1" price="30" isbn="123"/>
<list name="L1">
<book name="B2" price="20" isbn="234"/>
<list name="L2">
<cd name="C1" price="15"/>
<cd name="C2" price="5"/>
<book name="B3" price="10" isbn="345"/>
</list>
<cd name="C3" price="15"/>
<book name="B4" price="60" isbn="456"/>
</list>
</list>
如何获取嵌套列表的值?
谢谢大家! 由于
list
包含子属性,因此从nList.getLength()-1
循环到0
将避免许多问题
对于列表,我们需要子属性book
和cd
的值(价格)。因此,从最后一个循环到第一个循环将有助于我们将子属性的值存储在数据中
作为优先步骤
现在,为了得到列表的总价格,我们迭代了所有书籍和cd的节点列表。
我们将构成清单价格的所有值相加
下面是(e.getTagName()=“list”&&n.hasChildNodes()
)的代码
NodeList books=e.getElementsByTagName(“book”);
NodeList cd=e.getElementsByTagName(“cd”);
System.out.println(books.getLength());
System.out.println(cd.getLength());
双倍标价=0;
对于(int i=0;我非常感谢你!我认为这将解决我的问题。很高兴它有帮助!!:)
public class ManageList implements Assignment7 {
private HashMap<String, Double> data = new HashMap<String, Double>();
@Override
public void loadXml(File input) throws Exception {
// given in the readme
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
// get filename => absolute path
String filename = input.getAbsolutePath();
Document doc = db.parse(new File(filename));
// Normalize the XML Structure
doc.getDocumentElement().normalize();
// get the root element from XML document
// Element root = doc.getDocumentElement();
// ####################################
// acces elements and their attributes and store it in a hashmap
// ####################################
NodeList nl = doc.getElementsByTagName("*");
storeNodes(nl);
//System.out.println(Arrays.asList(data));
}
@Override
public Optional<Double> getPrice(String item) {
return null;
}
public void storeNodes(NodeList nl) {
for (int i = 0; i < nl.getLength(); i++) {
Node n = nl.item(i);
int type = n.getNodeType();
if (type == Node.ELEMENT_NODE) {
Element e = (Element) n;
if (e.getTagName() == "book" || e.getTagName() == "cd") {
data.put(e.getAttribute("name"), Double.parseDouble(e.getAttribute("price")));
}
if (e.getTagName() == "list" && n.hasChildNodes()) {
String name = e.getAttribute("name");
//here i get a NumberFormatException
//data.put(name, Double.parseDouble(e.getAttribute("price")));
//just to show output
data.put(name, 0.0);
}
storeNodes(n.getChildNodes());
}
}
}
[{B2=20.0, C3=15.0, B3=10.0, B4=60.0, L1=0.0, L2=0.0, root=0.0, C1=15.0, B1=30.0, C2=5.0}]
NodeList books = e.getElementsByTagName("book");
NodeList cd = e.getElementsByTagName("cd");
System.out.println(books.getLength());
System.out.println(cd.getLength());
double listPrice = 0;
for(int i=0;i<books.getLength();i++) {
Node t = books.item(i);
Element e1 = (Element)t;
/**This can be reduced if we loop from nList.getLength()-1 to 0, Since the data already exists in data.
//if (!data.containsKey(e1.getAttribute("name"))){
// data.put(e1.getAttribute("name"),Double.parseDouble(e1.getAttribute("price")));
//
//}
*/
listPrice += Double.parseDouble(e1.getAttribute("price"));
}
for(int i=0;i<cd.getLength();i++){
Node t = cd.item(i);
Element e1 = (Element)t;
listPrice += Double.parseDouble(e1.getAttribute("price"));
}