android 解析XML 工具类

/**

 * Created by John on 2016/3/29.

 */

public class XmlParser {

    private static final String ns = null;

    /**

     * 创建一个解析器

     * @param is 传入数据的输入流

     * @return 返回一个装有entry标签的arraylist

     * @throws XmlPullParserException 抛出异常

     * @throws IOException 抛出异常

     */

    public List parse(InputStream is) throws XmlPullParserException, IOException {

        try {

            XmlPullParser parser = Xml.newPullParser();

            parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);

            parser.setInput(is, null);

            parser.nextTag();

            return readFeed(parser);

        } finally {

            is.close();

        }

    }

    /**

     * 获取一个feed标签

     * @param parser 传入解析器

     * @return 返回一个List，将所有的entry字段封装在里面

     * @throws IOException 抛出异常

     * @throws XmlPullParserException 抛出异常

     */

    private List readFeed(XmlPullParser parser) throws IOException, XmlPullParserException {

        List entries = new ArrayList();

        parser.require(XmlPullParser.START_TAG,ns,"feed");

        while(parser.next() != XmlPullParser.END_TAG){

            continue;

        }

        String name = parser.getName();

        if (name.equals("entry")){

            entries.add(readEntry(parser));

        }else {

            skip(parser);

        }

        return entries;

    }

    /**

     * 获取entry标签

     * @param parser 传入解析器

     * @return 返回一个Entry数据，传入实体类以便于使用

     * @throws IOException 抛出异常

     * @throws XmlPullParserException 抛出异常

     */

    private Entry readEntry(XmlPullParser parser) throws IOException, XmlPullParserException {

        parser.require(XmlPullParser.START_TAG,ns,"entry");

        String title = null;

        String link = null;

        String summary = null;

        while (parser.next() != XmlPullParser.END_TAG){

            if (parser.getEventType() != XmlPullParser.START_TAG){

                continue;

            }

            String name = parser.getName();

            if (name.equals("title")){

                title = readTitle(parser);

            }else if (name.equals("link")){

                link = readLink(parser);

            }else if(name.equals("summary")){

                summary = readSummary(parser);

            }else {

                skip(parser);

            }

        }

        return new Entry(title,summary,link);

    }

    /**

     * 获取summary标签

     * @param parser 传入解析器

     * @return 返回一个标签

     * @throws IOException 抛出异常

     * @throws XmlPullParserException 抛出异常

     */

    private String readSummary(XmlPullParser parser) throws IOException, XmlPullParserException {

        parser.require(XmlPullParser.START_TAG,ns,"summary");

        String summary = readText(parser);

        parser.require(XmlPullParser.END_TAG,ns,"summary");

        return summary;

    }

    /**

     * 获取link标签

     * @param parser 传入解析器

     * @return 返回一个link标签

     * @throws IOException 抛出异常

     * @throws XmlPullParserException 抛出异常

     */

    private String readLink(XmlPullParser parser) throws IOException, XmlPullParserException {

        String link = "";

        parser.require(XmlPullParser.START_TAG,ns,"link");

        String tag = parser.getName();

        String relType = parser.getAttributeValue(null,"rel");

        if (tag.equals("link")){

            if (relType.equals("alternate")){

                link = parser.getAttributeValue(null,"href");

                parser.nextTag();

            }

        }

        parser.require(XmlPullParser.END_TAG,ns,"link");

        return link;

    }

    /**

     * 获取title标签

     * @param parser 传入解析器

     * @return 返回一个标签

     * @throws IOException 抛出异常

     * @throws XmlPullParserException 抛出异常

     */

    private String readTitle(XmlPullParser parser) throws IOException, XmlPullParserException {

        parser.require(XmlPullParser.START_TAG,ns,"title");

        String title = readText(parser);

        parser.require(XmlPullParser.END_TAG,ns,"title");

        return title;

    }

    /**

     * 获取标签中的文本

     * @param parser 传入解析器

     * @return 返回一个字符串

     * @throws IOException 抛出异常

     * @throws XmlPullParserException 抛出异常

     */

    private String readText(XmlPullParser parser) throws IOException, XmlPullParserException {

        String result = "";

        if (parser.next() == XmlPullParser.TEXT){

            result = parser.getText();

            parser.nextTag();

        }

        return result;

    }

    /**

     * 跳过不需要的标签

     * @param parser 传入解析工具parser

     * @throws XmlPullParserException 抛出异常

     * @throws IOException 抛出异常

     */

    private void skip(XmlPullParser parser) throws XmlPullParserException, IOException {

        if (parser.getEventType() != XmlPullParser.START_TAG){

//            throw new IllegalStateException();

        }

        int depth = 1;

        while (depth != 0){

            switch (parser.next()){

                case XmlPullParser.END_TAG:

                    depth --;

                    break;

                case XmlPullParser.START_TAG:

                    depth ++;

                    break;

            }

        }

    }

    /**

     * 创建一个Entry实体类

     */

    public static class Entry{

        public final String title;

        public final String link;

        public final String summary;

        private Entry(String title, String summary, String link) {

            this.title = title;

            this.summary = summary;

            this.link = link;

        }

    }

}