我很难弄清楚如何编写一个循环来从给定的XML文档中检索值以简化我将给你一个xml文件的样本
</solution>
<solution>
<cost>505.9208295302417</cost>
<routes>
<route>
<driverId>noDriver</driverId>
<vehicleId>1_1</vehicleId>
<start>0.0</start>
<act type="service">
<serviceId>5 </serviceId>
<arrTime>109.9819741964403</arrTime>
<endTime>119.9819741964403</endTime>
</act>
<end>229.9639483928806</end>
</route>
<route>
<driverId>noDriver</driverId>
<vehicleId>3_1</vehicleId>
<start>0.0</start>
<act type="service">
<serviceId>4 </serviceId>
<arrTime>109.98190391287031</arrTime>
<endTime>119.98190391287031</endTime>
</act>
<act type="service">
<serviceId>2 </serviceId>
<arrTime>119.98282618841856</arrTime>
<endTime>129.98282618841856</endTime>
</act>
<act type="service">
<serviceId>1 </serviceId>
<arrTime>129.98372097890456</arrTime>
<endTime>139.98372097890456</endTime>
</act>
<act type="service">
<serviceId>3 </serviceId>
<arrTime>139.9846432544528</arrTime>
<endTime>149.9846432544528</endTime>
</act>
<end>259.9668316441239</end>
</route>
</routes>
</solution>
</solutions>所以基本上我在代码中我将向您展示的是仅从有成本= 505.9208295302417的节点获取价值，请不要考虑这部分代码，所以下一步是检索driverid``, vehicleid and行为，我知道有一个缺少for循环但我不知道放在哪里!!请有人帮忙。我需要的所需输出就像每个vehicleid获取列表行为值一样
java代码
public static void main(String[] args) {
try {
int totalVehicle;
totalVehicle = 2;
File fXmlFile = new File("C:/Users/HP/Desktop/solution.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
doc.getDocumentElement().normalize();
Double requiredCost = 505.9208295302417;
System.out.println("Root element :" + doc.getDocumentElement().getNodeName());
// NodeList nList = doc.getElementsByTagName("route");
System.out.println("----------------------------");
NodeList nodeList = doc.getElementsByTagName("solution");
for (int i = 0; i < nodeList.getLength(); i++) {
Node solutionNode = nodeList.item(i);
if (solutionNode.getNodeType() == Node.ELEMENT_NODE) {
Element solutionElement = (Element) solutionNode;
Node costNode = solutionElement.getElementsByTagName("cost").item(0);
Node route = solutionElement.getElementsByTagName("routes").item(0);
// if correct cost, proceed to parse further
Double costValue = Double.valueOf(costNode.getTextContent());
if (Double.compare(requiredCost, costValue) == 0) {
System.out.println("working");
// there you go, found the node with the cost 505.9208295302417
// now just parse all the node elements you need here
System.out.println("cost : "
+ solutionElement.getElementsByTagName("cost")
.item(0).getTextContent());
for (int h = 0; h < totalVehicle; h++) {
System.out.println("DriverId : "
+ solutionElement.getElementsByTagName("driverId")
.item(h).getTextContent().toString());
System.out.println("vehicleId : "
+ solutionElement.getElementsByTagName("vehicleId")
.item(h).getTextContent());
NodeList optionList = solutionElement.getElementsByTagName("act");
System.out.println(optionList.getLength());
for (int j = 0; j < optionList.getLength(); ++j)
{
for(int k =0;k<1;++k){
Element option = (Element) optionList.item(j);
String optionText = option.getTextContent();
//address.add(optionText.replaceAll("[^A-Za-z]"," "));
System.out.println("Citizen :"+optionText.replaceAll("[^A-Za-z]"," "));}
;
}
正如其他人所建议的那样，使用xpath会容易得多，但如果绝对要求你循环使用所有这些东西，那就把问题分解成更小，更易于管理的部分。我想我会尝试一下，我有一个完整的，有效的解决方案来解决你的问题。
我们的想法是将xml分解为Java对象并使用这些对象来完成您需要的工作。
public static void main(String... args) throws SAXException, IOException, ParserConfigurationException {
Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder()
.parse(new File("/home/william/Documents/test.xml"));
doc.getDocumentElement().normalize();
NodeList nodeList = doc.getElementsByTagName("solution");
for (int i = 0; i < nodeList.getLength(); i++) {
Node solutionNode = nodeList.item(i);
try {
System.out.println(Solution.newInstance(solutionNode).toString());
} catch (Exception e) {
// do something
e.printStackTrace();
}
}
}
在这里，您的原始文档解析方式与解决方法相同，但解决方案是您自己的类，您可以将逻辑放入：
public class Solution {
private final double cost;
private final Collection<Route> routes;
public static final Solution newInstance(Node solution) throws Exception {
return new Solution(solution);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("solution:");
sb.append(System.lineSeparator());
sb.append("--------");
sb.append(System.lineSeparator());
sb.append("cost:");
sb.append(this.cost);
for (Route route : this.routes) {
sb.append(route.toString());
}
return sb.toString();
}
private Solution(Node solution) throws Exception {
if (solution.getNodeType() == Node.ELEMENT_NODE) {
Element solutionElement = (Element) solution;
this.cost = Double.valueOf(solutionElement.getElementsByTagName("cost").item(0).getTextContent());
this.routes = Routes.get(solutionElement.getElementsByTagName("routes").item(0));
} else {
// TODO something?
this.cost = 0D;
this.routes = Collections.emptyList();
}
}
}
请注意，在main方法中，您需要检查成本。我已经将所有类变量getter方法都删除了，如果需要从对象外部读取它们，请添加所需的方法。所以例如在你的Solution类中添加一个getCost()方法然后在main方法中你可以检查适当的：if (solution.getCost() == requiredCost) { ...
在这里，根据您的要求，您可以根据需要向类成员添加getter。我刚刚覆盖了toString()方法，以便打印您可以阅读的内容。
Routes是一个util类，用于在Route节点的子节点之外创建<routes>对象的集合。
public class Routes {
private final Collection<Route> items;
public static Collection<Route> get(Node routes) throws Exception {
return new Routes(routes).items;
}
private Routes() {
this.items = new ArrayList<>();
}
private Routes(Node routes) throws Exception {
this.items = new ArrayList<>();
NodeList routesList = routes.getChildNodes();
for (int i = 0; i < routesList.getLength(); i++) {
Node route = routesList.item(i);
if (Node.ELEMENT_NODE == route.getNodeType()) {
items.add(Route.newInstance(route));
} else {
// TODO something?
}
}
}
}
Acts类与Routes类具有相似的逻辑（同样的事情，但对于行为）：
public class Acts {
private Collection<Act> items;
public static Collection<Act> get(NodeList acts) throws Exception {
return new Acts(acts).items;
}
private Acts() {
this.items = new ArrayList<>();
}
private Acts(NodeList acts) throws Exception {
this.items = new ArrayList<>();
for (int i = 0; i < acts.getLength(); i++) {
Node act = acts.item(i);
if (Node.ELEMENT_NODE == act.getNodeType()) {
this.items.add(Act.newInstance(act));
} else {
// TODO something?
}
}
}
}
最后，每个人Act：
public class Act {
private final String service;
private final double arrTime;
private final double endTime;
public static Act newInstance(Node act) throws Exception {
return new Act(act);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Act");
sb.append(System.lineSeparator());
sb.append("arr time");
sb.append(System.lineSeparator());
sb.append(this.arrTime);
sb.append(System.lineSeparator());
sb.append("end time:");
sb.append(System.lineSeparator());
sb.append(this.endTime);
sb.append(System.lineSeparator());
sb.append("service:");
sb.append(System.lineSeparator());
sb.append(this.service);
return sb.toString();
}
private Act(Node act) throws Exception {
Element actElement = (Element) act;
this.service = actElement.getAttribute("service");
this.arrTime = Double.valueOf(actElement.getElementsByTagName("arrTime").item(0).getTextContent());
this.endTime = Double.valueOf(actElement.getElementsByTagName("endTime").item(0).getTextContent());
}
}