怎么进行JSOUP 爬虫的分析

蜗牛互联网技术资讯2021-12-132910

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规则编写说明文档

通用选择器（*）是隐含在没有元素选择器提供 (i.e. *.header and .header is equivalent).

样式	匹配	例子
`*`	任何元素	`*`
`tag`	通过Tga标签获取元素	`div`
`ns\|E`	elements of type E in the namespace ns	`fb\|name` finds `<fb:name>` elements
`#id`	elements with attribute ID of "id"	`div#wrap`, `#logo`
`.class`	elements with a class name of "class"	`div.left`, `.result`
`[attr]`	elements with an attribute named "attr" (with any value)	`a[href]`, `[title]`
`[^attrPrefix]`	elements with an attribute name starting with "attrPrefix". Use to find elements with HTML5 datasets	`[^data-]`, `div[^data-]`
`[attr=val]`	elements with an attribute named "attr", and value equal to "val"	`img[width=500]`, `a[rel=nofollow]`
`[attr="val"]`	elements with an attribute named "attr", and value equal to "val"	`span[hello="Cleveland"][goodbye="Columbus"]`, `a[rel="nofollow"]`
`[attr^=valPrefix]`	elements with an attribute named "attr", and value starting with "valPrefix"	`a[href^=http:]`
`[attr$=valSuffix]`	elements with an attribute named "attr", and value ending with "valSuffix"	`img[src$=.png]`
`[attr*=valContaining]`	elements with an attribute named "attr", and value containing "valContaining"	`a[href*=/search/]`
`[attr~=regex]`	elements with an attribute named "attr", and value matching the regular expression	`img[src~=(?i)\\.(png\|jpe?g)]`
	The above may be combined in any order	`div.header[title]`
	组合器
`E F`	an F element descended from an E element	`div a`, `.logo h2`
`E > F`	an F direct child of E	`ol > li`
`E + F`	an F element immediately preceded by sibling E	`li + li`, `div.head + div`
`E ~ F`	an F element preceded by sibling E	`h2 ~ p`
`E, F, G`	all matching elements E, F, or G	`a[href], div, h4`
	伪选择器
`:lt(n)`	elements whose sibling index is less than n	`td:lt(3)` finds the first 3 cells of each row
`:gt(n)`	elements whose sibling index is greater than n	`td:gt(1)` finds cells after skipping the first two
`:eq(n)`	elements whose sibling index is equal to n	`td:eq(0)` finds the first cell of each row
`:has(selector)`	elements that contains at least one element matching the selector	`div:has(p)` finds divs that contain p elements
`:not(selector)`	elements that do not match the selector. See also `Elements.not(String)`	`div:not(.logo)` finds all divs that do not have the "logo" class. `div:not(:has(div))` finds divs that do not contain divs.
`:contains(text)`	elements that contains the specified text. The search is case insensitive. The text may appear in the found element, or any of its descendants.	`p:contains(jsoup)` finds p elements containing the text "jsoup".
`:matches(regex)`	elements whose text matches the specified regular expression. The text may appear in the found element, or any of its descendants.	`td:matches(\\d+)` finds table cells containing digits. `div:matches((?i)login)` finds divs containing the text, case insensitively.
`:containsOwn(text)`	elements that directly contain the specified text. The search is case insensitive. The text must appear in the found element, not any of its descendants.	`p:containsOwn(jsoup)` finds p elements with own text "jsoup".
`:matchesOwn(regex)`	elements whose own text matches the specified regular expression. The text must appear in the found element, not any of its descendants.	`td:matchesOwn(\\d+)` finds table cells directly containing digits. `div:matchesOwn((?i)login)` finds divs containing the text, case insensitively.
	The above may be combined in any order and with other selectors	`.light:contains(name):eq(0)`
结构伪选择器
`:root`	The element that is the root of the document. In HTML, this is the `html` element	`:root`
`:nth-child(an+b)`	elements that have `an+b-1` siblings before it in the document tree, for any positive integer or zero value of `n`, and has a parent element. For values of `a` and `b` greater than zero, this effectively divides the element's children into groups of a elements (the last group taking the remainder), and selecting the bth element of each group. For example, this allows the selectors to address every other row in a table, and could be used to alternate the color of paragraph text in a cycle of four. The `a` and `b` values must be integers (positive, negative, or zero). The index of the first child of an element is 1. In addition to this, `:nth-child()` can take `odd` and `even` as arguments instead. `odd` has the same signification as `2n+1`, and `even` has the same signification as `2n`.	`tr:nth-child(2n+1)` finds every odd row of a table. `:nth-child(10n-1)` the 9th, 19th, 29th, etc, element. `li:nth-child(5)` the 5h li
`:nth-last-child(an+b)`	elements that have `an+b-1` siblings after it in the document tree. Otherwise like `:nth-child()`	`tr:nth-last-child(-n+2)` the last two rows of a table
`:nth-of-type(an+b)`	pseudo-class notation represents an element that has `an+b-1` siblings with the same expanded element name before it in the document tree, for any zero or positive integer value of n, and has a parent element	`img:nth-of-type(2n+1)`
`:nth-last-of-type(an+b)`	pseudo-class notation represents an element that has `an+b-1` siblings with the same expanded element name after it in the document tree, for any zero or positive integer value of n, and has a parent element	`img:nth-last-of-type(2n+1)`
`:first-child`	elements that are the first child of some other element.	`div > p:first-child`
`:last-child`	elements that are the last child of some other element.	`ol > li:last-child`
`:first-of-type`	elements that are the first sibling of its type in the list of children of its parent element	`dl dt:first-of-type`
`:last-of-type`	elements that are the last sibling of its type in the list of children of its parent element	`tr > td:last-of-type`
`:only-child`	elements that have a parent element and whose parent element hasve no other element children
`:only-of-type`	an element that has a parent element and whose parent element has no other element children with the same expanded element name
`:empty`	elements that have no children at all