XML子节点属性值 [英] XML child node attribute value
问题描述
我正在尝试阅读xml文件，例如：
I'm trying to read xml file, ex :
<entry>
<title>FEED TITLE</title>
<id>5467sdad98787ad3149878sasda</id>
<tempi type="application/xml">
<conento xmlns="http://mydomainname.com/xsd/radiofeed.xsd" madeIn="USA" />
</tempi>
</entry>
这是我到目前为止的代码：
Here is the code I have so far :
这是我尝试对此进行编码的尝试，该说不成功，这就是为什么我开始赏金。这是 http://pastebin.com/huKP4KED 。
Here is my attempt of trying to code this, what to say not successful thats why I started bounty. Here it is http://pastebin.com/huKP4KED .
Bounty更新：
我真的试过这几天了没想到会这么难，我会接受有用的链接/书籍/教程，但更喜欢代码，因为我昨天需要这样做。
I really really tried to do this for days now didn't expect to be so hard, I'll accept useful links/books/tutorials but prefer code because I need this done yesterday.
这是我需要的：
关于上面的xml：
- 我需要获得title，id的值
- tempi的属性值以及contento的madeIn属性值
什么是最好的要做到这一点？
What is the best way to do this ?
编辑：
@Pascal Thivent
@Pascal Thivent
也许创建方法可能是个好主意，比如public String getValue（String xml，Element elementname），你指定标签名称，方法返回标签值或标签属性（也许给它起名字）作为附加方法参数）如果该值不可用
Maybe creating method would be good idea like public String getValue(String xml, Element elementname), where you specify tag name, the method returns tag value or tag attribute(maybe give it name as additional method argument) if the value is not available
如果标签值不可用，我真的想获得某些标签值或属性，所以我我正在思考什么是最好的方法，因为我从来没有这样做过。
What I really want to get certain tag value or attribute if tag value(s) is not available, so I'm in the process of thinking what is the best way to do so since I've never done it before
推荐答案
最佳解决方案这是使用XPath。你的pastebin过期了，但这就是我收集的内容。假设我们有以下 feed.xml 文件：
The best solution for this is to use XPath. Your pastebin is expired, but here's what I gathered. Let's say we have the following feed.xml file:
<?xml version="1.0" encoding="UTF-8" ?>
<entries>
<entry>
<title>FEED TITLE 1</title>
<id>id1</id>
<tempi type="type1">
<conento xmlns="dontcare?" madeIn="MadeIn1" />
</tempi>
</entry>
<entry>
<title>FEED TITLE 2</title>
<id>id2</id>
<tempi type="type2">
<conento xmlns="dontcare?" madeIn="MadeIn2" />
</tempi>
</entry>
<entry>
<id>id3</id>
</entry>
</entries>
这是一个简短但可编译且可运行的概念验证（ feed.xml 同一目录中的文件）。
Here's a short but compile-and-runnable proof-of-concept (with feed.xml file in the same directory).
import javax.xml.xpath.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import java.io.*;
import java.util.*;
public class XPathTest {
static class Entry {
final String title, id, origin, type;
Entry(String title, String id, String origin, String type) {
this.title = title;
this.id = id;
this.origin = origin;
this.type = type;
}
@Override public String toString() {
return String.format("%s:%s(%s)[%s]", id, title, origin, type);
}
}
final static XPath xpath = XPathFactory.newInstance().newXPath();
static String evalString(Node context, String path) throws XPathExpressionException {
return (String) xpath.evaluate(path, context, XPathConstants.STRING);
}
public static void main(String[] args) throws Exception {
File file = new File("feed.xml");
Document document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(file);
NodeList entriesNodeList = (NodeList) xpath.evaluate("//entry", document, XPathConstants.NODESET);
List<Entry> entries = new ArrayList<Entry>();
for (int i = 0; i < entriesNodeList.getLength(); i++) {
Node entryNode = entriesNodeList.item(i);
entries.add(new Entry(
evalString(entryNode, "title"),
evalString(entryNode, "id"),
evalString(entryNode, "tempi/conento/@madeIn"),
evalString(entryNode, "tempi/@type")
));
}
for (Entry entry : entries) {
System.out.println(entry);
}
}
}
这会产生以下输出：
id1:FEED TITLE 1(MadeIn1)[type1]
id2:FEED TITLE 2(MadeIn2)[type2]
id3:()[]
注意使用XPath如何使值检索变得非常简单，直观，可读，简单，缺失的值也得到了优雅的处理。
Note how using XPath makes the value retrieval very simple, intuitive, readable, and straightforward, and "missing" values are also gracefully handled.
package javax.xml.xpath- http://www.w3.org/TR/xpath
- Wikipedia/XPath
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