怎么进行JSOUP爬虫的分析

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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|Eelements of type E in the namespace nsfb|name finds elements
    #idelements with attribute ID of "id"div#wrap, #logo
    .classelements 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 expressionimg[src~=(?i)\\.(png|jpe?g)]

    The above may be combined in any orderdiv.header[title]

    组合器



    E Fan F element descended from an E elementdiv a, .logo h2
    E > Fan F direct child of Eol > li
    E + Fan F element immediately preceded by sibling Eli + li, div.head + div
    E ~ Fan F element preceded by sibling Eh2 ~ p
    E, F, Gall matching elements E, F, or Ga[href], div, h4

    伪选择器



    :lt(n)elements whose sibling index is less than ntd:lt(3) finds the first 3 cells of each row
    :gt(n)elements whose sibling index is greater than ntd:gt(1) finds cells after skipping the first two
    :eq(n)elements whose sibling index is equal to ntd:eq(0) finds the first cell of each row
    :has(selector)elements that contains at least one element matching the selectordiv: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




    :rootThe 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 beforeit 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 afterit 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 elementimg: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 elementimg:nth-last-of-type(2n+1)
    :first-childelements that are the first child of some other element.div > p:first-child
    :last-childelements that are the last child of some other element.ol > li:last-child
    :first-of-typeelements that are the first sibling of its type in the list of children of its parent elementdl dt:first-of-type
    :last-of-typeelements that are the last sibling of its type in the list of children of its parent elementtr > td:last-of-type
    :only-childelements that have a parent element and whose parent element hasve no other element children

    :only-of-typean element that has a parent element and whose parent element has no other element children with the same expanded element name

    :emptyelements that have no children at all

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