개요 < url : Jsoup.org >  : JAVA 라이브러리의 일종으로 jQuery와 유사한 탐색 인터페이스를 활용하여 html문서의 Traversing -> Extracting 에 활용한다 

<dependency>
  <!-- jsoup HTML parser library @ http://jsoup.org/ -->
  <groupId>org.jsoup</groupId>
  <artifactId>jsoup</artifactId>
  <version>1.7.2</version>
</dependency> 

시작! connect 메서드를 써서 스트림으로 받아온당

Load Document from a URL

Connection Method는 jQuery처럼 Method Chaining을 지원한다

This method only suports web URLs (http and https protocols); if you need to load from a file, use the parse(File in, String charsetName) method instead.

요렇다네....

Load Document from a File

이제 데이타 추출

1. Extracting : Use DOM methods to navigate a document 

finding elements

• getElementById(String id)
• getElementsByTag(String tag)
• getElementsByClass(String className)
• getElementsByAttribute(String key) (and related methods)
• Element siblings: siblingElements(), firstElementSibling(), lastElementSibling();nextElementSibling(), previousElementSibling()
• Graph: parent(), children(), child(int index)

element data

• attr(String key) to get and attr(String key, String value) to set attributes
• attributes() to get all attributes
• id(), className() and classNames()
• text() to get and text(String value) to set the text content
• html() to get and html(String value) to set the inner HTML content
• outerHtml() to get the outer HTML value
• data() to get data content (e.g. of script and style tags)
• tag() and tagName() 

Manipulating HTML and text 

• append(String html), prepend(String html)
• appendText(String text), prependText(String text)
• appendElement(String tagName), prependElement(String tagName)
• html(String value)

2. Extracting : Use selector-syntax to find elements  

Jsoup 은 matching elements를 찾기위해 CSS(or jQuery) 처럼 selector-syntax를 지원한다.

 select method는 Document, Element, or in Elements 같은 문맥에서 사용가능하다 그래서 특정 element로 걸러내거나 체이닝하여 호출할 수 있다 

select 는 Elements list 를 돌려준다 (as Elements), 걔는 추출하고 결과를 조작하는등의 methods를 제공한다.


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]
• [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

 See the Selector API reference for the full supported list and details. 별거없음...

3. Extracting : Extract attributes, text, and HTML from elements 

요 methods는 element 데이타를 엑세스 하는 핵심이공, 다른 방법도 있는데? 

• Element.id()
• Element.tagName()
• Element.className() and Element.hasClass(String className) 

이러한 접근 방법의 모든 데이터를 변경하는 해당 세터 방법이 있당 / 아래는 그냥 참고 

• The reference documentation for Element and the collection Elements class
• Working with URLs
• finding elements with the CSS selector syntax

4. Extracting : Working with URLs

html문서에서 url은 종종 document's location에 상대적으로 씌여질 수 있는데
너가 Node.attr(String key) 요고로 href 속성 가져올때 고놈은 소스 html에 지정된 놈을 반환할거당

구래서 너가 절대 URL을 가져오길 바란다면? abs: 이게 있당 얘는 document base URI 를 제외한? 주소를 보내준다
attr("abs:href") 요렇게... 이런 사용에서는 document를 parsing 할때 base URI를 지정하는게 중요하다

너가 abs:를 사용 별로면  Node.absUrl(String key) 요런거두 있다
얘는 같다고 보면 되는데 근데 얘는 natural attribute key를 통해서 접속한다 

Example Program : List Links

 Example output (trimmed)