[英]How To read from Xml files based on nodes
我有一个Java代码可以从xml文件读取。 有三个不同的节点android,ios和web,我必须根据我指定的节点获取哈希图中的所有键值,如果我指定android,则来自android的所有键值应存储在has表中
我尝试使用代码,但发生了null异常,有人可以帮我吗
我的密码
public HashMap<String, String> readXML (String elementName)
throws ParserConfigurationException, SAXException, IOException {
HashMap<String, String> locator = new HashMap<>();
try {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
File file = new File("XML.xml");
Document doc = dBuilder.parse(file);
NodeList nList = doc.getElementsByTagName("android");
Element fileElementactivity=(Element)nList.item(0);
NodeList nListactivity = fileElementactivity.getElementsByTagName("activity");
Element fileElementactivityname=(Element)nListactivity.item(1);
NodeList nListkeys = fileElementactivityname.getElementsByTagName("keys");
Element fileElementkey=(Element)nListkeys.item(0);
NodeList nListkey = fileElementkey.getElementsByTagName("key");
System.out.println(nListkey);
for (int j = 0; j < nListkey.getLength(); j++) {
Node columnNode = nListkey.item(j);
Element columnElement = (Element) columnNode;
Node data = columnElement.getElementsByTagName("name").item(0);
String name = "";
if (data != null) {
name = data.getTextContent();
if (name.contentEquals(elementName)) {
data = columnElement.getElementsByTagName("type").item(0);
String type = data.getTextContent();
data = columnElement.getElementsByTagName("value").item(0);
String value = data.getTextContent();
System.out.println(name + "******" + type + " : " + value);
locator.put(type, value);
}
}
}
System.out.println(locator.size());
} catch (Exception e) {
e.printStackTrace();
}
return locator;
}
和我的xml
<object>
<android>
<activity>
<activity-name>UserProfileLoginActivity</activity-name>
<keys>
<key>
<name>fake</name>
<type>index</type>
<value>0</value>
</key>
<key>
<name>fake</name>
<type>name</type>
<value>signIn</value>
</key>
</keys>
</activity>
</android>
<ios>
<activity>
<activity-name>UserProfileLoginActivity</activity-name>
<keys>
<key>
<name>fake</name>
<type>index</type>
<value>0</value>
</key>
<key>
<name>fake</name>
<type>name</type>
<value>signIn</value>
</key>
</keys>
</activity>
</ios>
<web>
<activity>
<activity-name>UserProfileLoginActivity</activity-name>
<keys>
<key>
<name>fake</name>
<type>index</type>
<value>0</value>
</key>
<key>
<name>fake</name>
<type>name</type>
<value>signIn</value>
</key>
</keys>
</activity>
</web>
</object>
如果您愿意摆脱直接的org.w3c.dom。*受虐狂,也许Java 8库Dynamics可能会有所帮助。 同样直接,但空值安全且有用。
XmlDynamic example = new XmlDynamic(xmlStringOrReaderOrInputSourceEtc);
String target = "android";
Map<String, String> keyTypeToValue = example.get("object")
.get(target)
.get("activity|keys")
.children()
.collect(toMap(key -> key.get("type").asString(), key -> key.get("value").asString()));
// {name=signIn, index=0}
将其放在一种适用于“ ios”,“ web”等的方法中很简单。
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