帮助解析RSS提要。所有元素都返回null

时间：2011-06-24 18:45:23

标签： java android xml rss

我正在尝试解析rss feed，它似乎获得了所有节点但没有子元素，它们都返回null。

Java代码：

package com.nasutek.sliceoftech;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class RSSParser {
    private ArrayList<RSSPost> rssposts;
    private DocumentBuilderFactory factory;
    private DocumentBuilder builder;
    public RSSParser() {
        this.rssposts = new ArrayList<RSSPost>();
    }

    private String getNodeValue(NamedNodeMap map, String key) {
        String nodeValue = null;
        Node node = map.getNamedItem(key);
        if (node != null) {
            nodeValue = node.getNodeValue();
        }
        return nodeValue;
    }
    public List<RSSPost> getList() {
        return this.rssposts;
    }
    public void parse(InputStream inStream) {
        try {
            this.rssposts = new ArrayList<RSSPost>();
            this.factory = DocumentBuilderFactory.newInstance();
            this.builder = this.factory.newDocumentBuilder();
            this.builder.isValidating();
            Document doc = this.builder.parse(inStream, null);

            doc.getDocumentElement().normalize();

            NodeList itemList = doc.getElementsByTagName("item");
            final int length = itemList.getLength();

            for (int i = 0; i < length; i++) {
                final NamedNodeMap attr = itemList.item(i).getAttributes();
                final String rss_title = getNodeValue(attr, "title");
                final String rss_link = getNodeValue(attr, "link");
                final String rss_pubDate = getNodeValue(attr, "pubDate");
                final String rss_creator = getNodeValue(attr, "dc:creator");
                final String rss_sharelink = getNodeValue(attr, "guid");
                final String rss_description = getNodeValue(attr, "description");
                final String rss_content = getNodeValue(attr, "content:encoded");
                final String rss_thumbnail = itemList.item(i).getNodeName();

                RSSPost post = new RSSPost(rss_title,rss_link,rss_pubDate,rss_creator,rss_sharelink,rss_description,rss_content,rss_thumbnail);

                if (post.title != null) this.rssposts.add(post);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

RSS Feed：

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
    xmlns:content="http://purl.org/rss/1.0/modules/content/"
    xmlns:wfw="http://wellformedweb.org/CommentAPI/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:atom="http://www.w3.org/2005/Atom"
    xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
    xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
    >

<channel>
    <title>Slice of Tech &#187; Search Results  &#187;  Google</title>
    <atom:link href="http://www.sliceoftech.com/feed?s=Google" rel="self" type="application/rss+xml" />
    <link>http://www.sliceoftech.com</link>
    <description>Technology breaking news, reviews, and editorials</description>

    <lastBuildDate>Fri, 24 Jun 2011 04:43:11 +0000</lastBuildDate>
    <language>en</language>
    <sy:updatePeriod>hourly</sy:updatePeriod>
    <sy:updateFrequency>1</sy:updateFrequency>
    <generator>http://wordpress.org/?v=3.1.3</generator>
        <item>

        <title>Best Buy Joins the Music Cloud Bandwagon</title>
        <link>http://www.sliceoftech.com/2011/06/best-buy-joins-the-music-cloud-bandwagon/</link>
        <comments>http://www.sliceoftech.com/2011/06/best-buy-joins-the-music-cloud-bandwagon/#comments</comments>
        <pubDate>Wed, 22 Jun 2011 05:59:18 +0000</pubDate>
        <dc:creator>Kevin Nunez</dc:creator>
                <category><![CDATA[Cloud]]></category>

        <category><![CDATA[Best Buy]]></category>
        <category><![CDATA[Cloud computing]]></category>

        <guid isPermaLink="false">http://www.sliceoftech.com/?p=98</guid>
        <description><![CDATA[So we&#8217;ve seen cloud music storing services from Amazon, Google, and Apple &#8211; all of which work great. Best Buy, however, has decided to join the mix and come up with a cloud service themselves. They rolled out their new service called Music Cloud that lets you upload your audio to their servers and stream [...]]]></description>
            <content:encoded><![CDATA[<p style="text-align: left;"><a href="http://www.sliceoftech.com/wp-content/uploads/2011/06/Screen-Shot-2011-06-22-at-1.57.13-AM.png"><br />
<img class="aligncenter size-full wp-image-99" title="Screen Shot 2011-06-22 at 1.57.13 AM" src="http://www.sliceoftech.com/wp-content/uploads/2011/06/Screen-Shot-2011-06-22-at-1.57.13-AM.png" alt="" width="550" height="194" /></a></p>
<p style="text-align: left;">So we&#8217;ve seen cloud music storing services from Amazon, Google, and Apple &#8211; all of which work great. Best Buy, however, has decided to join the mix and come up with a cloud service themselves. They rolled out their new service called Music Cloud that lets you upload your audio to their servers and stream it from wherever you are. You can also save songs locally, and there&#8217;s apps for Android, BlackBerry, and iOS to manage and play your music. There are two versions of the service &#8211; Lite and Premium. Lite is free while premium is $3.99 per month, but Best Buy hasn&#8217;t disclosed in their official blog post what pro users will get over the free guys. Also, the service only catches songs from iTunes and not from anywhere else, so for those who avoid iTunes at all costs (don&#8217;t blame ya), you&#8217;re outta luck.</p>
<p style="text-align: left;">Why Best Buy would do this is beyond me, but I guess they thought it would be a good move to make. When it rains, it pours, and it&#8217;s certainly very &#8220;cloudy&#8221; in the tech world. Will you use Best Buy&#8217;s cloud service?</p>
<p>[via <a href="http://news.yahoo.com/s/digitaltrends/20110621/tc_digitaltrends/bestbuysoftlaunchesmusiccloudservice">Yahoo News</a>]<br />
Source: <a href="http://www.bestbuymobile.com/article/inside-best-buy-music-cloud">Best Buy Blog</a></p>
]]></content:encoded>
            <wfw:commentRss>http://www.sliceoftech.com/2011/06/best-buy-joins-the-music-cloud-bandwagon/feed/</wfw:commentRss>
        <slash:comments>0</slash:comments>

    <enclosure url="http://www.sliceoftech.com/wp-content/uploads/2011/06/Screen-Shot-2011-06-22-at-1.57.13-AM-300x105.png" length="32141" type="image/jpg" />  </item>
    </channel>
</rss>

1 个答案:

答案 0 :(得分：0)

看起来你有点混淆了。您已经使用getAttributes返回元素的属性，在您的情况下，item元素没有属性。如果你已经在guid元素上运行了那个，你将得到一个isPermaLink值。

这个例子让我得到了项目的细节：

http://javamix.wordpress.com/2009/06/09/read-rss-feeds-using-jsp/

因此，我使用了这一行而不是使用getAttributes：

final Element element = (Element)itemList.item(i);

然后得到一些数据是这种风格：

final String rss_title = getElementValue(element, "title");

我只能在Eclipse上运行这个，因为我没有Android可用。我不明白为什么它不适用于Android。

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