選擇器是 jsoup 用來從 html 文檔中對元素進行過濾的強大工具。
先看下面一段例子：
下面是 jsoup 所支持的選擇器列表：
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] [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 that have the attribute key, that its value matches the supplied regular expression; e.g. img[src~=(?i)\.(png|jpe?g)] *: all elements, e.g. * 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] 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 > p finds 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 el: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) el:gt(n): find elements whose sibling index is greater than n; e.g. div p:gt(2) el:eq(n): find elements whose sibling index is equal to n; e.g. form input:eq(1) el:has(seletor): find elements that contain elements matching the selector; e.g. div:has(p) el:contains(text): find elements that contain the given text. The search is case-insensitive; e.g. p:contains(jsoup) el:matches(regex): find elements whose text matches the specified regular expression; e.g. div:matches((?i)login). 相當(dāng)之強大，比我一直在用的 htmlparser 強多了。
