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所以，我相信答案可能會相當簡單。儘管如此，我一直試圖弄清楚這個問題已經一個多星期了，而且沒有運氣。我正在嘗試爲桌面/操作系統模擬器遊戲創建一個FileSystem。Java + XML |從同名節點的深層樹中訪問特定節點
目前，文件系統看起來是這樣的：（精簡略）
<system>
<info> <!-- Default information/data for this system -->
<top dir="/"/>
</info>
<files> <!-- File and Directory structure for this system -->
<dir name="home" owner="0" group="0" ownerp="rwx" groupp="r-x" otherp="r-x">
<dir name="cyanite" owner="1000" group="1000" ownerp="rwx" groupp="rwx" otherp="r-x">
<dir name="folder" owner="1000" group="1000" ownerp="rwx" groupp="rwx" otherp="r-x">
<dir name="folder" owner="1000" group="1000" ownerp="rwx" groupp="rwx" otherp="r-x">
<dir name="folder" owner="1000" group="1000" ownerp="rwx" groupp="rwx" otherp="r-x">
</dir>
</dir>
</dir>
</dir>
</dir>
<dir name="bin" owner="0" group="0" ownerp="rwx" groupp="r-x" otherp="r-x">
</dir>
<dir name="etc" owner="0" group="0" ownerp="rwx" groupp="r-x" otherp="r-x">
</dir>
<dir name="usr" owner="0" group="0" ownerp="rwx" groupp="r-x" otherp="r-x">
</dir>
</files>
</system>
這裏是我馬虎WIP代碼嘗試從文件中讀取：
System.out.println(fileNavigator.getDirectory("home"));
public ArrayList<String> getDirectory(String path) {
Document doc = ExitParser.getDocFromZip(system); // This loads the save file and returns the doc
NodeList dataList = doc.getElementsByTagName("files");
NodeList dataList2 = parsePath(dataList, path);
ArrayList<String> stringList = new ArrayList<String>();
try {
for(int i=0; i < dataList2.getLength(); i++) {
Node dataItem = dataList2.item(i);
Element elementDataItem = (Element)dataItem;
stringList.add(elementDataItem.getAttribute("name"));
}
} catch (NullPointerException e) {
stringList.add("NullPointerException");
}
return stringList;
}
public NodeList parsePath(NodeList nodelist, String path) {
Document doc = ExitParser.getDocFromZip(system); // This loads the save file and returns the doc
NodeList dataList = doc.getElementsByTagName("info");
if (path.startsWith(ExitParser.getAttributeValue(dataList, "top", "dir"))) {
// This simply grabs "top" from the FileSystem <info> area and strips it.
path.replaceFirst(Pattern.quote(ExitParser.getAttributeValue(dataList, "top", "dir")), "");
}
List<String> pathList = new ArrayList<String>();
if (path.contains("/")) {
pathList = new ArrayList<String>(Arrays.asList(path.split("/")));
} else if (path.contains("\\")) {
pathList = new ArrayList<String>(Arrays.asList(path.split("\\")));
} else {
pathList.add(path);
}
for (String string : pathList) {
System.out.println(string);
nodelist = ExitParser.getNextSetAttr(nodelist, string);
}
return nodelist;
}
public static NodeList getNextSetAttr(NodeList data, String attrName) {
try {
for(int i=0; i < data.getLength(); i++){
Element dataElement = (Element)data.item(i);
NodeList nodeList = dataElement.getElementsByTagName("dir");
Element nodeElement = (Element)nodeList.item(0);
if(nodeElement.hasAttribute("name")){
if (nodeElement.getAttribute("name").contains(attrName)) {
System.out.println(true);
return nodeList;
}
}
}
}
catch(Exception ex) {
System.out.println(ex.getMessage());
}
return null;
}
使用上面的代碼，我預計輸出爲[cyanite]，但我得到[home, cyanite, folder, folder, folder, bin, etc, usr]。
如果我將System.out.println(fileNavigator.getDirectory("home"));更改爲System.out.println(fileNavigator.getDirectory("home/cyanite"));，那麼我會得到[cyanite]。如果我將"home/cyanite"更改爲"bin"，我會得到[NullPointerException]。
對於[home, cyanite, folder, folder, folder, bin, etc, usr]這個問題似乎是父節點被添加到列表（即home，bin等，usr）以及所有子節點（即：文件夾，文件夾，文件夾）的問題。在我的使用案例中，我只希望獲取當前節點的子節點，而不是節點的子節點。
雖然我不確定爲什麼我不能訪問home以外的其他文件夾。