学步园

1,解析一个本地网页。

File input = new File("/tmp/input.html");
Document doc = Jsoup.parse(input, "UTF-8", "http://example.com/");

Elements links = doc.select("a[href]"); // a with href
Elements pngs = doc.select("img[src$=.png]");
  // img with src ending .png

Element masthead = doc.select("div.masthead").first();
  // div with class=masthead

Elements resultLinks = doc.select("h3.r > a"); // direct a after h3

2，描述

Selector overview

• tagname:
  find elements by tag, e.g. a
• ns|tag:
  find elements by tag in a namespace, e.g. fb|name finds <fb:name> elements
• #id:
  find elements by ID, e.g. #logo
• .class:
  find elements by class name, e.g. .masthead
• [attribute]:
  elements with attribute, e.g. [href]
• [^attr]:
  elements with an attribute name prefix, e.g. [^data-] finds
  elements with HTML5 dataset attributes
• [attr=value]:
  elements with attribute value, e.g. [width=500] (also quotable,
  likesequence")
• [attr^=value], [attr$=value], [attr*=value]:
  elements with attributes that start with, end with, or contain the value, e.g. [href*=/path/]
• [attr~=regex]:
  elements with attribute values that match the regular expression; e.g.img[src~=(?i)\.(png|jpe?g)]
• *:
  all elements, e.g. *

Selector combinations

• el#id:
  elements with ID, e.g. div#logo
• el.class:
  elements with class, e.g. div.masthead
• el[attr]:
  elements with attribute, e.g. a[href]
• Any combination, e.g. a[href].highlight
• ancestor
child: child elements that descend from ancestor, e.g. .body
p finds p elements anywhere under a block with class
  "body"
• parent
> child: child elements that descend directly from parent, e.g. div.content
> pfinds p elements; and body
> * finds the direct children of the body tag
• siblingA
+ siblingB: finds sibling B element immediately preceded by sibling A, e.g.div.head
+ div
• siblingA
~ siblingX: finds sibling X element preceded by sibling A, e.g. h1
~ p
• el,
el, el: group multiple selectors, find unique elements that match any of the selectors; e.g. div.masthead,
div.logo

Pseudo selectors

• :lt(n):
  find elements whose sibling index (i.e. its position in the DOM tree relative to its parent) is less than n;
  e.g. td:lt(3)
• :gt(n):
  find elements whose sibling index is greater than n; e.g. div
p:gt(2)
• :eq(n):
  find elements whose sibling index is equal to n; e.g. form
input:eq(1)
• :has(seletor):
  find elements that contain elements matching the selector; e.g. div:has(p)
• :not(selector):
  find elements that do not match the selector; e.g. div:not(.logo)
• :contains(text):
  find elements that contain the given text. The search is case-insensitive; e.g. p:contains(jsoup)
• :containsOwn(text):
  find elements that directly contain the given text
• :matches(regex):
  find elements whose text matches the specified regular expression; e.g.div:matches((?i)login)
• :matchesOwn(regex):
  find elements whose own text matches the specified regular expression
• Note that the above indexed pseudo-selectors are 0-based, that is, the first element is at index 0, the second at 1, etc