我正在尝试使用 Stax 解析开放街道 map 的 XML 结构。在我的实现中,我使用 XMLStreamConstants.START_ELEMENT 和 XMLStreamConstants.END_ELEMENT 来认识元素。
OpenStreetMaps 结构具有诸如标签之类的元素,它们还描述了节点以及道路。下面是一个结构示例:
<node id="2311741639" ... lat="50.7756648" lon="6.0844948">
<tag k="entrance" v="yes"/>
</node>
<way id="4964449" visible="true" ... uid="67862">
<nd ref="27290865"/>
...
<tag k="highway" v="residential"/>
...
</way>
如果解析器读取Tag-Element,如何区分节点和方式?
最佳答案
您可以使用节点表示的 ArrayDeque
,或者如果层次结构的深度较小,甚至可以构建一个临时的类似 DOM 的结构。
这是一个 ArrayDeque
的示例...
假设此 XML 文件名为 stuff.xml
:
<?xml version="1.0" encoding="UTF-8"?>
<stuff>
<node id="2311741639" lat="50.7756648" lon="6.0844948">
<tag k="entrance" v="yes"/>
</node>
<way id="4964449" visible="true" uid="67862">
<nd ref="27290865"/>
<tag k="highway" v="residential"/>
</way>
</stuff>
假设文件位于路径:/my/path/
这里是代码(try/catch Java 6 风格):
InputStream is = null;
XMLStreamReader reader = null;
try {
is = new FileInputStream(new File("/my/path/stuff.xml"));
XMLInputFactory xif = XMLInputFactory.newInstance();
reader = xif.createXMLStreamReader(is);
ArrayDeque<String> nodes = new ArrayDeque<String>();
while (reader.hasNext()) {
int current = reader.next();
switch (current) {
case XMLStreamConstants.START_ELEMENT: {
nodes.add(reader.getLocalName());
System.out.println("START: " + nodes.getLast());
if (nodes.size() > 1) {
Iterator<String> iterator = nodes.descendingIterator();
// skipping first one as it's already represented
iterator.next();
while (iterator.hasNext()) {
System.out.println("\t in " + iterator.next());
}
}
break;
}
case XMLStreamConstants.END_ELEMENT: {
System.out.println("END: " + nodes.removeLast());
Iterator<String> iterator = nodes.descendingIterator();
while (iterator.hasNext()) {
System.out.println("\t in " + iterator.next());
}
break;
}
}
}
}
catch (FileNotFoundException fnfe) {
fnfe.printStackTrace();
}
catch (XMLStreamException xse) {
xse.printStackTrace();
}
finally {
if (reader != null) {
try {
reader.close();
is.close();
}
catch (XMLStreamException xse) {
xse.printStackTrace();
}
catch (IOException ioe) {
ioe.printStackTrace();
}
}
}
输出:
START: stuff
START: node
in stuff
START: tag
in node
in stuff
END: tag
in node
in stuff
END: node
in stuff
START: way
in stuff
START: nd
in way
in stuff
END: nd
in way
in stuff
START: tag
in way
in stuff
END: tag
in way
in stuff
END: way
in stuff
END: stuff
关于java - 使用 STAX API 进行 XML 解析,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19724033/