使用 Java 读取 XML 文件
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Read XML files with Java
提问by Bishan
I need to read a XML file with java. File structure as below.
我需要用 java 读取 XML 文件。文件结构如下。
<?xml version="1.0" encoding="UTF-8"?>
<xml_tool xmlns:md="http://www.example.com/XT/1.0/">
<md:header>
<md:application_version>1.0</md:application_version>
<md:export_date>19-04-2012</md:export_date>
<md:export_time>14:55</md:export_time>
<md:export_user>USER01</md:export_user>
</md:header>
<md:table table_name="CUSTOMER" key="customer number" record_count="2" column_count="5">
<md:record>
<md:column name="customer_number">123456</md:column>
<md:column name="reg_date">01-04-2012</md:column>
<md:column name="customer_name">Test Customer</md:column>
<md:column name="customer_type">Normal </md:column>
<md:column name="comments">This is a test record</md:column>
</md:record>
<md:record>
<md:column name="customer_number">555111</md:column>
<md:column name="reg_date">02-04-2012</md:column>
<md:column name="customer_name">Test Customer</md:column>
<md:column name="customer_type">VIP </md:column>
<md:column name="comments">This is a test record</md:column>
</md:record>
</md:table>
</xml_tool>
I have read How to read XML file in Java – (DOM Parser)example and try to do my work. But I'm unable to read XML file successfully.
我已阅读How to read XML file in Java – (DOM Parser)示例并尝试完成我的工作。但我无法成功读取 XML 文件。
My Code
我的代码
try {
File fXmlFile = new File("c:\file.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
doc.getDocumentElement().normalize();
NodeList nList = doc.getElementsByTagName("md:record");
for (int i = 0; i < nList.getLength(); i++) {
Node node = nList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) node;
System.out.println(getTagValue("md:column", eElement));
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
private static String getTagValue(String sTag, Element eElement) {
NodeList nlList = eElement.getElementsByTagName(sTag).item(0).getChildNodes();
Node nValue = (Node) nlList.item(0);
return nValue.getNodeValue();
}
and Result is
结果是
123456
555111
How could I read this XML file?
我怎么能读取这个 XML 文件？
回答by Sachin Mhetre
Update your for loop...
更新你的 for 循环...
for (int i = 0; i < nList.getLength(); i++)
{
Node node = nList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE)
{
if(eElement.hasChildNodes())
{
NodeList nl = node.getChildNodes();
for(int j=0; j<nl.getLength(); j++)
{
Node nd = nl.item(j);
System.out.println(nd.getTextContent());
}
}
}
}
回答by rob
Currently you're doing very inexact queries (namely, getElementsByTagName(...), which is not restricted to first-level descendants). In getTagValue(...), you'll need to iterate over the NodeListin order to get all the data for all of the children--in which case, maybe you intend for the method to return a List<String>. Or, better yet, move that NodeListto your other method and loop over it there.
目前您正在执行非常不精确的查询（即，getElementsByTagName(...)不限于一级后代）。在 中getTagValue(...)，您需要遍历NodeList以获取所有子项的所有数据——在这种情况下，您可能打算让该方法返回一个List<String>. 或者，更好的是，将其移动NodeList到您的其他方法并在那里循环。
To get all the data, including the header, you will need to recursively iterate over all the elements, starting with the root node.
要获取包括标题在内的所有数据，您需要从根节点开始递归迭代所有元素。
That said, there's a much better way. You can use JAXBto bind your XML schema to your POJO (plain-old Java object) data model. Then all the loading will be done automatically, and you can concentrate on the program logic.
也就是说，有一个更好的方法。您可以使用JAXB将 XML 模式绑定到 POJO（普通 Java 对象）数据模型。然后所有的加载都会自动完成，你可以专注于程序逻辑。
