Java 说 XML 文档格式不正确
Java 的 XML 解析器似乎认为我的 XML 文档在根元素之后的格式不正确。但我用几种工具验证了它,但它们都不同意。这可能是我的代码中的错误,而不是文档本身的错误。我真的很感激你们能为我提供的任何帮助。
这是我的 Java 方法:
private void loadFromXMLFile(File f) throws ParserConfigurationException, IOException, SAXException {
File file = f;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db;
Document doc = null;
db = dbf.newDocumentBuilder();
doc = db.parse(file);
doc.getDocumentElement().normalize();
String desc = "";
String due = "";
String comment = "";
NodeList tasksList = doc.getElementsByTagName("task");
for (int i = 0; i tasksList.getLength(); i++) {
NodeList attributes = tasksList.item(i).getChildNodes();
for (int j = 0; i < attributes.getLength(); j++) {
Node attribute = attributes.item(i);
if (attribute.getNodeName() == "description") {
desc = attribute.getTextContent();
}
if (attribute.getNodeName() == "due") {
due = attribute.getTextContent();
}
if (attribute.getNodeName() == "comment") {
comment = attribute.getTextContent();
}
tasks.add(new Task(desc, due, comment));
}
desc = "";
due = "";
comment = "";
}
}
以下是我尝试加载的 XML 文件:
<?xml version="1.0"?>
<tasklist>
<task>
<description>Task 1</description>
<due>Due date 1</due>
<comment>Comment 1</comment>
<completed>false</completed>
</task>
<task>
<description>Task 2</description>
<due>Due date 2</due>
<comment>Comment 2</comment>
<completed>false</completed>
</task>
<task>
<description>Task 3</description>
<due>Due date 3</due>
<comment>Comment 3</comment>
<completed>true</completed>
</task>
</tasklist>
这是 java 为我抛出的错误消息:
run:
[Fatal Error] tasks.xml:28:3: The markup in the document following the root element must be well-formed.
May 17, 2010 6:07:02 PM todolist.TodoListGUI <init>
SEVERE: null
org.xml.sax.SAXParseException: The markup in the document following the root element must be well-formed.
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:239)
at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:283)
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:208)
at todolist.TodoListGUI.loadFromXMLFile(TodoListGUI.java:199)
at todolist.TodoListGUI.<init>(TodoListGUI.java:42)
at todolist.Main.main(Main.java:25)
BUILD SUCCESSFUL (total time: 19 seconds)
供参考 TodoListGUI.java:199 是
doc = db.parse(file);
如果上下文对这里的任何人有帮助,我会尝试编写一个简单的 GUI 应用程序来管理待办事项列表,该列表可以读取和写入定义任务的 XML 文件。
Java's XML parser seems to be thinking that my XML document is not well formed following the root element. But I've validated it with several tools and they all disagree. It's probably an error in my code rather than in the document itself. I'd really appreciate any help you all could offer me.
Here is my Java method:
private void loadFromXMLFile(File f) throws ParserConfigurationException, IOException, SAXException {
File file = f;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db;
Document doc = null;
db = dbf.newDocumentBuilder();
doc = db.parse(file);
doc.getDocumentElement().normalize();
String desc = "";
String due = "";
String comment = "";
NodeList tasksList = doc.getElementsByTagName("task");
for (int i = 0; i tasksList.getLength(); i++) {
NodeList attributes = tasksList.item(i).getChildNodes();
for (int j = 0; i < attributes.getLength(); j++) {
Node attribute = attributes.item(i);
if (attribute.getNodeName() == "description") {
desc = attribute.getTextContent();
}
if (attribute.getNodeName() == "due") {
due = attribute.getTextContent();
}
if (attribute.getNodeName() == "comment") {
comment = attribute.getTextContent();
}
tasks.add(new Task(desc, due, comment));
}
desc = "";
due = "";
comment = "";
}
}
The following is the XML file I'm trying to load:
<?xml version="1.0"?>
<tasklist>
<task>
<description>Task 1</description>
<due>Due date 1</due>
<comment>Comment 1</comment>
<completed>false</completed>
</task>
<task>
<description>Task 2</description>
<due>Due date 2</due>
<comment>Comment 2</comment>
<completed>false</completed>
</task>
<task>
<description>Task 3</description>
<due>Due date 3</due>
<comment>Comment 3</comment>
<completed>true</completed>
</task>
</tasklist>
And here is the error message java is throwing for me:
run:
[Fatal Error] tasks.xml:28:3: The markup in the document following the root element must be well-formed.
May 17, 2010 6:07:02 PM todolist.TodoListGUI <init>
SEVERE: null
org.xml.sax.SAXParseException: The markup in the document following the root element must be well-formed.
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:239)
at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:283)
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:208)
at todolist.TodoListGUI.loadFromXMLFile(TodoListGUI.java:199)
at todolist.TodoListGUI.<init>(TodoListGUI.java:42)
at todolist.Main.main(Main.java:25)
BUILD SUCCESSFUL (total time: 19 seconds)
For reference TodoListGUI.java:199 is
doc = db.parse(file);
If context is helpful to anyone here, I'm trying to write a simple GUI application to manage a todo list that can read and write to and from XML files defining the tasks.
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评论(6)
无论如何,Scala REPL 成功解析了您的标记。
scala> val tree = <tasklist>
| <task>
| <description>Task 1</description>
| <due>Due date 1</due>
| <comment>Comment 1</comment>
| <completed>false</completed>
| </task>
| <task>
| <description>Task 2</description>
| <due>Due date 2</due>
| <comment>Comment 2</comment>
| <completed>false</completed>
| </task>
| <task>
| <description>Task 3</description>
| <due>Due date 3</due>
| <comment>Comment 3</comment>
| <completed>true</completed>
| </task>
| </tasklist>
tree: scala.xml.Elem =
<tasklist>
<task>
<description>Task 1</description>
<due>Due date 1</due>
<comment>Comment 1</comment>
<completed>false</completed>
</task>
<task>
<description>Task 2</description>
<due>Due date 2</due>
<comment>Comment 2</comment>
<completed>false</completed>
</task>
<task>
<description>Task 3</description>
<due>Due date 3</due>
<comment>Comment 3</comment>
<completed>true</completed>
</task>
</tasklist>
另一个值得一提的是,这是我将 xml 保存到名为 test.xml
的文件中并通过 xmllint。
[jhr@Macintosh] [~]
xmllint test.xml
<?xml version="1.0"?>
<tasklist>
<task>
<description>Task 1</description>
<due>Due date 1</due>
<comment>Comment 1</comment>
<completed>false</completed>
</task>
<task>
<description>Task 2</description>
<due>Due date 2</due>
<comment>Comment 2</comment>
<completed>false</completed>
</task>
<task>
<description>Task 3</description>
<due>Due date 3</due>
<comment>Comment 3</comment>
<completed>true</completed>
</task>
</tasklist>
似乎还好。很可能您有一些在实际文件中看不到的杂散字符。尝试在编辑器中查看实际文件,该编辑器将显示不可打印的字符,就像其他人建议的那样,如果这不是英语 UTF-8 机器,您可能会有一些解析器看不到的 Unicode 字符。或者你没有加载你认为的文件。在将文件送入解析器之前,进行逐步调试并查看文件的实际内容是什么。
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这一特殊异常表明 XML 文档中存在多个根元素。换句话说,
不是唯一的根元素。以 XML 文档为例,请考虑一个不带
元素但在根中包含三个
元素的文档。这会导致这种异常。由于您发布的 XML 文件看起来不错,所以问题出在其他地方。看起来它没有解析您期望它解析的 XML 文件。为了快速调试,请将以下内容添加到方法顶部:
在磁盘文件系统中找到该文件并验证它。
This particular exception indicates that there is more than one root element in the XML document. In other words, the
<tasklist>
is not the only root element. To take your XML document as an example, think of one without the<tasklist>
element and with three<task>
elements in the root. This would cause this kind of exception.Since the XML file you posted looks fine, the problem lies somewhere else. It look like that it is not parsing the XML file you expect that it is parsing. For quick debugging, add the following to top of your method:
Locate the file in the disk file system and verify it.