JSoup:获取维基百科页面摘要

Question

我使用MediaWiki API获取维基百科页面，在获取html内容后，我尝试使用

p:not(h2 ~ p)

要获得页面摘要段落，它应该是目录元素之前的段落，它获得了想要的部分，但有额外的段落，问题在哪里？

Answer 1

p:not(h2 ~ p)获取页面上同一父级中之前没有h2的每一个段落。这包括嵌套的段落、完全在主要内容之外的段落等，因为这些段落中没有一个与h2本身共享相同的父元素。你不想要这些；您只希望出现在父元素中h2元素之前的段落。

为此，您需要将外部p选择器锚定到父元素。您想要的父元素是.mw-parser-output:

.mw-parser-output > p:not(h2 ~ p)

Answer 2

代码：

public static void main(String[] args){
Document doc = null;
String url = "https://en.wikipedia.org/wiki/Nico_Ditch";
try {
doc = Jsoup.parse(new URL(url).openStream(), "UTF-8", url);
} catch (IOException e) {
e.printStackTrace();
}
Elements els = doc.select(".mw-parser-output > p:not(h2 ~ p)");
System.out.println(els);
// System.out.println(doc);
}

运行输出：

<p class="mw-empty-elt"> </p>
<p><b>Nico Ditch</b> is a six-mile (9.7&nbsp;km) long linear <a href="/wiki/Earthworks_(archaeology)" title="Earthworks (archaeology)">earthwork</a> between <a href="/wiki/Ashton-under-Lyne" title="Ashton-under-Lyne">Ashton-under-Lyne</a> and <a href="/wiki/Stretford" title="Stretford">Stretford</a> in Greater Manchester, England. It was dug as a defensive fortification, or possibly a boundary marker, between the 5th and 11th centuries. </p>
<p>The ditch is still visible in short sections, such as a 330-yard (300&nbsp;m) stretch in <a href="/wiki/Denton,_Greater_Manchester" title="Denton, Greater Manchester">Denton</a> Golf Course. In the parts which survive, the ditch is 4–5 yards (3.7–4.6&nbsp;m) wide and up to 5 feet (1.5&nbsp;m) deep. Part of the earthwork is protected as a <a href="/wiki/Scheduled_Ancient_Monument" class="mw-redirect" title="Scheduled Ancient Monument">Scheduled Ancient Monument</a>. </p>

进程已完成，退出代码为0