XML解析器无法正常工作，我收到以下错误：
org.xml.sax.SAXParseException; lineNumber：1; columnNumber：1; 序言中不能有内容。在 com.sun.org.apache.xerces.internal.parsers.DOMParser.parse（DOMParser.java:257） 在 com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse（DocumentBuilderImpl.java:339） 在openexcel.xmlreader.main（xmlreader.java:24）
这是我的XML文档
</service>
</services>
<solutions>
<solution>
<cost>505.9214670746815</cost>
<routes>
<route>
<driverId>noDriver</driverId>
<vehicleId>1_1</vehicleId>
<start>0.0</start>
<act type="service">
<serviceId>5 WassimKarim maudarbaccus</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 Jean Nicolas Yung</serviceId>
<arrTime>109.98190391287031</arrTime>
<endTime>119.98190391287031</endTime>
</act>
<act type="service">
<serviceId>2 George Bush</serviceId>
<arrTime>119.98282618841856</arrTime>
<endTime>129.98282618841856</endTime>
</act>
<act type="service">
<serviceId>3 Saddam Usain</serviceId>
<arrTime>129.98343325287408</arrTime>
<endTime>139.98343325287408</endTime>
</act>
<act type="service">
<serviceId>1 Barack OBama</serviceId>
<arrTime>139.98435552842233</arrTime>
<endTime>149.98435552842233</endTime>
</act>
<end>259.9673220629237</end>
</route>
</routes>
</solution>
<solution>
<cost>505.9208295302417</cost>
<routes>
<route>
<driverId>noDriver</driverId>
<vehicleId>1_2</vehicleId>
<start>0.0</start>
<act type="service">
<serviceId>5 Oppa Gamnamstyle</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 Jean Nicolas Yung</serviceId>
<arrTime>109.98190391287031</arrTime>
<endTime>119.98190391287031</endTime>
</act>
<act type="service">
<serviceId>2 Emilie Sparks</serviceId>
<arrTime>119.98282618841856</arrTime>
<endTime>129.98282618841856</endTime>
</act>
<act type="service">
<serviceId>1 Denzel Wshington</serviceId>
<arrTime>129.98372097890456</arrTime>
<endTime>139.98372097890456</endTime>
</act>
<act type="service">
<serviceId>3 Mona Lisa</serviceId>
<arrTime>139.9846432544528</arrTime>
<endTime>149.9846432544528</endTime>
</act>
<end>259.9668316441239</end>
</route>
</routes>
</solution>
</solutions>
</problem>
我正在尝试为XML文件中的每个实体获取几个字段（cost，driverid，vehicleid，start，act，serviceId，arrTime）。
到目前为止我一直在尝试的是
答案 0 :(得分：0)
例外
您获得的错误是由于您的XML格式不正确，XML的开头似乎不正确，您可以删除吗
</service>
</services>
并将其替换为
<problem>
这样你的XML就这样开始了：
<problem>
<solutions>
<solution>
..
这将匹配文件的结束标记
</solution>
</solutions>
</problem>
我尝试了它，现在可以解析了。
提取值
如上所述，获得有效的XML后。
我们说我们有以下课程
class Solution {
private Double cost;
private List<Route> routes = new ArrayList<>();
// Getters/Setters
}
class Route {
private String driverId;
private String vehicleId;
private Double start;
private Double end;
private Act act;
// Getters/Setters
}
class Act {
private String type;
private String serviceId;
private Double arrTime;
private Double endTime;
// Getters/Setters
}
你需要创建一个处理程序，在读取xml
时构建你的对象class MyHandler extends DefaultHandler {
// This will hold the result of the parsing
private List<Solution> solutions = new ArrayList<>();
// These are local variables used to create the objects
private Solution solution;
private Route route;
private Act act;
// The name of the element we are reading
private String currentElementName = "";
private static String SOLUTION_TAG = "solution";
private static String ROUTE_TAG = "route";
private static String ACT_TAG = "act";
private static String COST_TAG = "cost";
private static String DRIVERID_TAG = "driverId";
private static String VEHICLEID_TAG = "vehicleId";
private static String START_TAG = "start";
private static String END_TAG = "end";
private static String SERVICEID_TAG = "serviceId";
private static String ARRTIME_TAG = "arrTime";
private static String ENDTIME_TAG = "endTime";
private static String ACT_TYPE_ATTRIBUTE = "type";
public List<Solution> getSolutions() {
return solutions;
}
// Called when we start a new element, that is where we create the objects
public void startElement(String uri, String localName, String qName, Attributes attributes) {
currentElementName = qName;
if (qName.equalsIgnoreCase(SOLUTION_TAG)) {
solution = new Solution();
} else if (qName.equalsIgnoreCase(ROUTE_TAG)) {
route = new Route();
} else if (qName.equalsIgnoreCase(ACT_TAG)) {
act = new Act();
act.setType(attributes.getValue(ACT_TYPE_ATTRIBUTE));
}
}
// Called when we ending an element, that is where we stick the objects one in an other
public void endElement(String uri, String localName, String qName) {
if (qName.equalsIgnoreCase(ACT_TAG)) {
route.setAct(act);
} else if (qName.equalsIgnoreCase(ROUTE_TAG)) {
solution.getRoutes().add(route);
} else if (qName.equalsIgnoreCase(SOLUTION_TAG)) {
solutions.add(solution);
}
currentElementName = "";
}
// Called when we reading the text inside an element, that is where we set values to the object attributes
public void characters(char ch[], int start, int length) {
String s = new String(ch, start, length);
if(currentElementName.equalsIgnoreCase(COST_TAG)) {
solution.setCost(Double.valueOf(s));
} else if(currentElementName.equalsIgnoreCase(DRIVERID_TAG)) {
route.setDriverId(s);
} else if(currentElementName.equalsIgnoreCase(VEHICLEID_TAG)) {
route.setVehicleId(s);
} else if(currentElementName.equalsIgnoreCase(START_TAG)) {
route.setStart(Double.valueOf(s));
} else if(currentElementName.equalsIgnoreCase(END_TAG)) {
route.setEnd(Double.valueOf(s));
} else if(currentElementName.equalsIgnoreCase(SERVICEID_TAG)) {
act.setServiceId(s);
} else if(currentElementName.equalsIgnoreCase(ARRTIME_TAG)) {
act.setArrTime(Double.valueOf(s));
} else if(currentElementName.equalsIgnoreCase(ENDTIME_TAG)) {
act.setEndTime(Double.valueOf(s));
}
}
}
然后您可以通过这种方式简单地解析XML：
MyHandler myHandler = new MyHandler();
try {
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
saxParser.parse(new InputSource(new StringReader(xml)), myHandler);
} catch (Exception e) {
e.printStackTrace();
}
并且您已将所有文件解析为处理程序中的解决方案列表，您可以通过这种方式获取
myHandler.getSolutions();