Java Xml解析嵌套标记返回null
您好,我是XML解析新手,并完成了关于XML解析的google教程。在本教程中,他们将使用: 所以我想用关于文章作者的信息来扩展它,我尝试了一下,但是无论我在author标记(uri标记和name标记)中使用什么,它总是返回null “搜索标签”发生在我的文件中Java Xml解析嵌套标记返回null,java,android,xml,xml-parsing,Java,Android,Xml,Xml Parsing,您好,我是XML解析新手,并完成了关于XML解析的google教程。在本教程中,他们将使用: 所以我想用关于文章作者的信息来扩展它,我尝试了一下,但是无论我在author标记(uri标记和name标记)中使用什么,它总是返回null “搜索标签”发生在我的文件中 /** *此类解析stackoverflow.com中的XML提要。 *给定提要的InputStream表示形式,它将返回条目列表, *其中,每个列表元素表示XML提要中的单个条目(post)。 */ 公共类StackOverflowX
/**
*此类解析stackoverflow.com中的XML提要。
*给定提要的InputStream表示形式,它将返回条目列表,
*其中,每个列表元素表示XML提要中的单个条目(post)。
*/
公共类StackOverflowXmlParser{
私有静态最终字符串ns=null;
//我们不使用名称空间
公共列表解析(InputStream in)抛出XmlPullParserException,IOException{
试一试{
XmlPullParser=Xml.newPullParser();
setFeature(XmlPullParser.FEATURE_进程_名称空间,false);
setInput(in,null);
parser.nextTag();
返回readFeed(解析器);
}最后{
in.close();
}
}
私有列表readFeed(XmlPullParser解析器)抛出XmlPullParserException,IOException{
列表项=新的ArrayList();
require(XmlPullParser.START_标记,ns,“feed”);
while(parser.next()!=XmlPullParser.END_标记){
if(parser.getEventType()!=XmlPullParser.START_标记){
继续;
}
String name=parser.getName();
//首先查找条目标记
如果(名称等于(“条目”)){
add(readEntry(解析器));
}
否则{
跳过(解析器);
}
}
返回条目;
}
//此类表示XML提要中的单个条目(post)。
//它包括数据成员“标题”、“链接”和“摘要”
公共静态类条目
{
公开最终字符串评级;
公共最终字符串标题;
公共最终字符串链接;
公共最终字符串作者;
私有条目(字符串分级、字符串标题、字符串链接、字符串作者)
{
这个。评级=评级;
this.title=标题;
this.link=link;
this.author=作者;
}
}
//解析条目的内容。如果它遇到标题、摘要或链接标记,则将其交给
//关
//到各自的“读取”方法进行处理。否则,跳过标记。
私有条目readEntry(XmlPullParser解析器)抛出XmlPullParserException,IOException{
require(XmlPullParser.START_标记,ns,“entry”);
字符串评级=空;
字符串标题=null;
字符串链接=null;
字符串author=null;
while(parser.next()!=XmlPullParser.END_标记){
if(parser.getEventType()!=XmlPullParser.START_标记){
继续;
}
String name=parser.getName();
如果(名称等于(“re:rank”)){
rating=读取rating_名称(解析器);
}
如果(名称等于(“头衔”)){
title=readTitle\u名称(解析器);
}
else if(name.equals(“id”)){
link=readLink\u名称(解析器);
}
else if(name.equals(“name”)){
author=readAuthor\u名称(解析器);
}
其他的
{
跳过(解析器);
}
}
返回新条目(评级、标题、链接、作者);
}
//处理提要中的标题标记。
私有字符串readRating_name(XmlPullParser)抛出IOException,XmlPullParserException{
require(XmlPullParser.START_标记,ns,“re:rank”);
字符串评级=readText(解析器);
require(XmlPullParser.END_标记,ns,“re:rank”);
回报率;
}
私有字符串readTitle_name(XmlPullParser解析器)引发IOException,XmlPullParserException{
require(XmlPullParser.START_标记,ns,“title”);
字符串title=readText(解析器);
require(XmlPullParser.END_标记,ns,“title”);
返回标题;
}
私有字符串readLink_name(XmlPullParser解析器)引发IOException,XmlPullParserException{
require(XmlPullParser.START_标记,ns,“id”);
字符串链接=读文本(解析器);
require(XmlPullParser.END_标记,ns,“id”);
返回链接;
}
私有字符串readAuthor_name(XmlPullParser解析器)引发IOException,XmlPullParserException{
require(XmlPullParser.START_标记,ns,“name”);
字符串author=readText(解析器);
require(XmlPullParser.END_标记,ns,“name”);
返回作者;
}
//对于标记标题和摘要,提取其文本值。
私有字符串readText(XmlPullParser)
抛出IOException、XmlPullParserException{
字符串结果=”;
if(parser.next()==XmlPullParser.TEXT){
结果=parser.getText();
parser.nextTag();
}
返回结果;
}
//跳过解析器不感兴趣的标记。使用深度处理嵌套标记。例如。,
//如果开始标记后的下一个标记不是匹配的结束标记,则它将一直运行,直到找到它为止
//查找匹配的END_标记(如“depth”的值为0所示)。
私有void skip(XmlPullParser解析器)抛出XmlPullParserException,IOException{
if(parser.getEventType()!=XmlPullParser.START_标记){
抛出新的非法状态异常();
}
int深度=1;
while(深度!=0){
开关(parser.next()){
case XmlPullParser.END_标记:
深度--;
打破
case XmlPullParser.START_标记:
深度++;
打破
}
}
}
}
我的c
/**
* This class parses XML feeds from stackoverflow.com.
* Given an InputStream representation of a feed, it returns a List of entries,
* where each list element represents a single entry (post) in the XML feed.
*/
public class StackOverflowXmlParser {
private static final String ns = null;
// We don't use namespaces
public List<Entry> parse(InputStream in) throws XmlPullParserException, IOException {
try {
XmlPullParser parser = Xml.newPullParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(in, null);
parser.nextTag();
return readFeed(parser);
} finally {
in.close();
}
}
private List<Entry> readFeed(XmlPullParser parser) throws XmlPullParserException, IOException {
List<Entry> entries = new ArrayList<Entry>();
parser.require(XmlPullParser.START_TAG, ns, "feed");
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
// Starts by looking for the entry tag
if (name.equals("entry")) {
entries.add(readEntry(parser));
}
else {
skip(parser);
}
}
return entries;
}
// This class represents a single entry (post) in the XML feed.
// It includes the data members "title," "link," and "summary."
public static class Entry
{
public final String rating;
public final String title;
public final String link;
public final String author;
private Entry(String rating, String title, String link, String author)
{
this.rating = rating;
this.title = title;
this.link = link;
this.author = author;
}
}
// Parses the contents of an entry. If it encounters a title, summary, or link tag, hands them
// off
// to their respective "read" methods for processing. Otherwise, skips the tag.
private Entry readEntry(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "entry");
String rating = null;
String title = null;
String link = null;
String author = null;
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (name.equals("re:rank")){
rating = readRating_name(parser);
}
else if (name.equals("title")){
title = readTitle_name(parser);
}
else if (name.equals("id")){
link = readLink_name(parser);
}
else if (name.equals("name")){
author = readAuthor_name(parser);
}
else
{
skip(parser);
}
}
return new Entry(rating, title, link, author);
}
// Processes title tags in the feed.
private String readRating_name(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "re:rank");
String rating = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "re:rank");
return rating;
}
private String readTitle_name(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;
}
private String readLink_name(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "id");
String link = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "id");
return link;
}
private String readAuthor_name(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "name");
String author = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "name");
return author;
}
// For the tags title and summary, extracts their text values.
private String readText(XmlPullParser parser)
throws IOException, XmlPullParserException {
String result = "";
if (parser.next() == XmlPullParser.TEXT) {
result = parser.getText();
parser.nextTag();
}
return result;
}
// Skips tags the parser isn't interested in. Uses depth to handle nested tags. i.e.,
// if the next tag after a START_TAG isn't a matching END_TAG, it keeps going until it
// finds the matching END_TAG (as indicated by the value of "depth" being 0).
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;
}
}
}
}
// Uploads XML from stackoverflow.com, parses it, and combines it with
// HTML markup. Returns HTML string.
private String loadXmlFromNetwork(String urlString) throws XmlPullParserException, IOException
{
InputStream stream = null;
StackOverflowXmlParser stackOverflowXmlParser = new StackOverflowXmlParser();
List<Entry> entries = null;
StringBuilder htmlString = new StringBuilder();
try {
stream = downloadUrl(urlString);
entries = stackOverflowXmlParser.parse(stream);
// Makes sure that the InputStream is closed after the app is
// finished using it.
}
finally
{
if (stream != null)
{
stream.close();
}
}
// Content section
for (Entry entry : entries)
{
// <a href="Link">Name link</a>
String question = getString(R.string.question);
String rating = getString(R.string.rating);
String author = getString(R.string.author);
// Question link + title
htmlString.append("<p>" + question + "<a href='" + entry.link + "'>" + entry.title + "</a><br />");
htmlString.append(rating + entry.rating + "<br />");
htmlString.append(author + entry.author + "</p>");
}
return htmlString.toString();
}
String xml = "xml here...";
XMLSerializer xmlSerializer = new XMLSerializer();
JSON json = xmlSerializer.read( xml );