标签：Node return String 爬虫 parentNode Jsoup HTML Document public

1 概述

简介

Jsoup是一款基于Java的HTML解析器，它提供了一种简单、灵活且易于使用的API，用于从URL、文件或字符串中解析HTML文档。它可以帮助开发人员从HTML文档中提取数据、操作DOM元素、处理表单提交等。

主要特点

Jsoup的主要特点包括：

简单易用：Jsoup提供了一系列简单的API，使得解析HTML变得非常容易。开发人员可以使用类似于jQuery的选择器语法来选择DOM元素，从而方便地提取所需的数据。
强大的HTML处理能力：Jsoup支持HTML5标准，并且能够处理不完整或损坏的HTML文档。它可以自动修复HTML中的错误，并且在解析过程中保留原始的HTML结构。
安全可靠：Jsoup内置了防止XSS攻击的机制，可以自动过滤恶意的HTML标签和属性，保证解析过程的安全性。
支持CSS选择器：Jsoup支持使用CSS选择器来选择DOM元素，这使得开发人员可以更加灵活地定位和操作HTML文档中的元素。
与Java集成：Jsoup是基于Java开发的，可以与Java程序无缝集成。开发人员可以使用Java的各种特性和库来处理解析后的数据。

应用场景

Jsoup 在大数据、云计算领域的应用场景包括但不限于：

网页数据抓取： Jsoup可以帮助开发人员从网页中提取所需的数据，例如爬取新闻、商品信息等。通过解析HTML文档，可以快速准确地获取所需的数据。
数据清洗与处理：在云计算中，大量的数据需要进行清洗和处理。Jsoup可以帮助开发人员解析HTML文档，提取出需要的数据，并进行进一步的处理和分析。
网页内容分析： Jsoup可以帮助开发人员对网页内容进行分析，例如提取关键词、统计标签出现次数等。这对于搜索引擎优化、网页分析等领域非常有用。

竞品

爬虫解析HTML文档的工具有：

[java] Jsoup

https://github.com/jhy/jsoup

https://jsoup.org/

https://mvnrepository.com/artifact/org.jsoup/jsoup/1.12.2

[python] Beautiful Jsoup

https://www.crummy.com/software/BeautifulSoup/

https://github.com/DeronW/beautifulsoup/tree/v4.4.0

https://beautifulsoup.readthedocs.io/

https://beautifulsoup.readthedocs.io/zh-cn/v4.4.0/

2 使用指南

本章节，基于 1.14.3 版本

依赖引入

<!-- https://mvnrepository.com/artifact/org.jsoup/jsoup --> 
<dependency>     
	<groupId>org.jsoup</groupId>     
	<artifactId>jsoup</artifactId>
    <!-- 1.12.2 / 1.14.3 / 1.17.2 -->	
	<version>1.14.3</version> 
</dependency>

核心 API

org.jsoup.Jsoup

package org.jsoup;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import javax.annotation.Nullable;
import org.jsoup.helper.DataUtil;
import org.jsoup.helper.HttpConnection;
import org.jsoup.nodes.Document;
import org.jsoup.parser.Parser;
import org.jsoup.safety.Cleaner;
import org.jsoup.safety.Safelist;
import org.jsoup.safety.Whitelist;

public class Jsoup {
    private Jsoup() {
    }

    public static Document parse(String html, String baseUri) {
        return Parser.parse(html, baseUri);
    }

    public static Document parse(String html, String baseUri, Parser parser) {
        return parser.parseInput(html, baseUri);
    }

    public static Document parse(String html, Parser parser) {
        return parser.parseInput(html, "");
    }

    public static Document parse(String html) {
        return Parser.parse(html, "");
    }

    public static Connection connect(String url) {
        return HttpConnection.connect(url);
    }

    public static Connection newSession() {
        return new HttpConnection();
    }

    public static Document parse(File file, @Nullable String charsetName, String baseUri) throws IOException {
        return DataUtil.load(file, charsetName, baseUri);
    }

    public static Document parse(File file, @Nullable String charsetName) throws IOException {
        return DataUtil.load(file, charsetName, file.getAbsolutePath());
    }

    public static Document parse(File file, @Nullable String charsetName, String baseUri, Parser parser) throws IOException {
        return DataUtil.load(file, charsetName, baseUri, parser);
    }

    public static Document parse(InputStream in, @Nullable String charsetName, String baseUri) throws IOException {
        return DataUtil.load(in, charsetName, baseUri);
    }

    public static Document parse(InputStream in, @Nullable String charsetName, String baseUri, Parser parser) throws IOException {
        return DataUtil.load(in, charsetName, baseUri, parser);
    }

    public static Document parseBodyFragment(String bodyHtml, String baseUri) {
        return Parser.parseBodyFragment(bodyHtml, baseUri);
    }

    public static Document parseBodyFragment(String bodyHtml) {
        return Parser.parseBodyFragment(bodyHtml, "");
    }

    public static Document parse(URL url, int timeoutMillis) throws IOException {
        Connection con = HttpConnection.connect(url);
        con.timeout(timeoutMillis);
        return con.get();
    }

    public static String clean(String bodyHtml, String baseUri, Safelist safelist) {
        Document dirty = parseBodyFragment(bodyHtml, baseUri);
        Cleaner cleaner = new Cleaner(safelist);
        Document clean = cleaner.clean(dirty);
        return clean.body().html();
    }

    /** @deprecated */
    @Deprecated
    public static String clean(String bodyHtml, String baseUri, Whitelist safelist) {
        return clean(bodyHtml, baseUri, (Safelist)safelist);
    }

    public static String clean(String bodyHtml, Safelist safelist) {
        return clean(bodyHtml, "", safelist);
    }

    /** @deprecated */
    @Deprecated
    public static String clean(String bodyHtml, Whitelist safelist) {
        return clean(bodyHtml, (Safelist)safelist);
    }

    public static String clean(String bodyHtml, String baseUri, Safelist safelist, Document.OutputSettings outputSettings) {
        Document dirty = parseBodyFragment(bodyHtml, baseUri);
        Cleaner cleaner = new Cleaner(safelist);
        Document clean = cleaner.clean(dirty);
        clean.outputSettings(outputSettings);
        return clean.body().html();
    }

    /** @deprecated */
    @Deprecated
    public static String clean(String bodyHtml, String baseUri, Whitelist safelist, Document.OutputSettings outputSettings) {
        return clean(bodyHtml, baseUri, (Safelist)safelist, outputSettings);
    }

    public static boolean isValid(String bodyHtml, Safelist safelist) {
        return (new Cleaner(safelist)).isValidBodyHtml(bodyHtml);
    }

    /** @deprecated */
    @Deprecated
    public static boolean isValid(String bodyHtml, Whitelist safelist) {
        return isValid(bodyHtml, (Safelist)safelist);
    }
}

org.jsoup.nodes.Node

关键 API

Jsoup遍历DOM树的方法

根据id查找元素: getElementById(String id)

根据标签查找元素: getElementsByTag(String tag)

根据class查找元素: getElementsByClass(String className)

根据属性查找元素: getElementsByAttribute(String key)

兄弟遍历方法: siblingElements(), firstElementSibling(), lastElementSibling(); nextElementSibling(), previousElementSibling()

层级之间遍历: parent(), children(), child(int index)

这些方法会返回Element或者Elements节点对象，这些对象可以使用下面的方法获取一些属性：

attr(String key): 获取某个属性值
attributes(): 获取节点的所有属性
id(): 获取节点的id
className(): 获取当前节点的class名称
classNames(): 获取当前节点的所有class名称
text(): 获取当前节点的textNode内容
html(): 获取当前节点的 inner HTML
outerHtml(): 获取当前节点的 outer HTML
data(): 获取当前节点的内容，用于script或者style标签等
tag(): 获取标签
tagName(): 获取当前节点的标签名称

有了这些API，就像 JQuery 一样很便利的操作DOM。

Jsoup也支持修改DOM树结构：

text(String value): 设置内容

html(String value): 直接替换HTML结构

append(String html): 元素后面添加节点

prepend(String html): 元素前面添加节点

appendText(String text), prependText(String text)

appendElement(String tagName), prependElement(String tagName)

源码

package org.jsoup.nodes;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import javax.annotation.Nullable;
import org.jsoup.SerializationException;
import org.jsoup.helper.Validate;
import org.jsoup.internal.StringUtil;
import org.jsoup.select.NodeFilter;
import org.jsoup.select.NodeTraversor;
import org.jsoup.select.NodeVisitor;

public abstract class Node implements Cloneable {
    static final List<Node> EmptyNodes = Collections.emptyList();
    static final String EmptyString = "";
    @Nullable
    Node parentNode;
    int siblingIndex;

    protected Node() {
    }

    public abstract String nodeName();

    protected abstract boolean hasAttributes();

    public boolean hasParent() {
        return this.parentNode != null;
    }

    public String attr(String attributeKey) {
		...
	}
	
    public abstract Attributes attributes();
	
    public int attributesSize() {
        return this.hasAttributes() ? this.attributes().size() : 0;
    }

    public Node attr(String attributeKey, String attributeValue) {
        attributeKey = NodeUtils.parser(this).settings().normalizeAttribute(attributeKey);
        this.attributes().putIgnoreCase(attributeKey, attributeValue);
        return this;
    }

    public boolean hasAttr(String attributeKey) {
        Validate.notNull(attributeKey);
        if (!this.hasAttributes()) {
            return false;
        } else {
            if (attributeKey.startsWith("abs:")) {
                String key = attributeKey.substring("abs:".length());
                if (this.attributes().hasKeyIgnoreCase(key) && !this.absUrl(key).isEmpty()) {
                    return true;
                }
            }

            return this.attributes().hasKeyIgnoreCase(attributeKey);
        }
    }

    public Node removeAttr(String attributeKey) {
        Validate.notNull(attributeKey);
        if (this.hasAttributes()) {
            this.attributes().removeIgnoreCase(attributeKey);
        }

        return this;
    }

    public Node clearAttributes() {
        if (this.hasAttributes()) {
            Iterator<Attribute> it = this.attributes().iterator();

            while(it.hasNext()) {
                it.next();
                it.remove();
            }
        }

        return this;
    }

    public abstract String baseUri();

    protected abstract void doSetBaseUri(String var1);

    public void setBaseUri(String baseUri) {
        Validate.notNull(baseUri);
        this.doSetBaseUri(baseUri);
    }

    public String absUrl(String attributeKey) {
        Validate.notEmpty(attributeKey);
        return this.hasAttributes() && this.attributes().hasKeyIgnoreCase(attributeKey) ? StringUtil.resolve(this.baseUri(), this.attributes().getIgnoreCase(attributeKey)) : "";
    }

    protected abstract List<Node> ensureChildNodes();

    public Node childNode(int index) {
        return (Node)this.ensureChildNodes().get(index);
    }

    public List<Node> childNodes() {
        if (this.childNodeSize() == 0) {
            return EmptyNodes;
        } else {
            List<Node> children = this.ensureChildNodes();
            List<Node> rewrap = new ArrayList(children.size());
            rewrap.addAll(children);
            return Collections.unmodifiableList(rewrap);
        }
    }

    public List<Node> childNodesCopy() {
        List<Node> nodes = this.ensureChildNodes();
        ArrayList<Node> children = new ArrayList(nodes.size());
        Iterator var3 = nodes.iterator();

        while(var3.hasNext()) {
            Node node = (Node)var3.next();
            children.add(node.clone());
        }

        return children;
    }

    public abstract int childNodeSize();

    protected Node[] childNodesAsArray() {
        return (Node[])this.ensureChildNodes().toArray(new Node[0]);
    }

    public abstract Node empty();

    @Nullable
    public Node parent() {
        return this.parentNode;
    }

    @Nullable
    public final Node parentNode() {
        return this.parentNode;
    }

    public Node root() {
        Node node;
        for(node = this; node.parentNode != null; node = node.parentNode) {
        }

        return node;
    }

    @Nullable
    public Document ownerDocument() {
        Node root = this.root();
        return root instanceof Document ? (Document)root : null;
    }

    public void remove() {
        Validate.notNull(this.parentNode);
        this.parentNode.removeChild(this);
    }

    public Node before(String html) {
        this.addSiblingHtml(this.siblingIndex, html);
        return this;
    }

    public Node before(Node node) {
        Validate.notNull(node);
        Validate.notNull(this.parentNode);
        this.parentNode.addChildren(this.siblingIndex, node);
        return this;
    }

    public Node after(String html) {
        this.addSiblingHtml(this.siblingIndex + 1, html);
        return this;
    }

    public Node after(Node node) {
        Validate.notNull(node);
        Validate.notNull(this.parentNode);
        this.parentNode.addChildren(this.siblingIndex + 1, node);
        return this;
    }

    private void addSiblingHtml(int index, String html) {
        Validate.notNull(html);
        Validate.notNull(this.parentNode);
        Element context = this.parent() instanceof Element ? (Element)this.parent() : null;
        List<Node> nodes = NodeUtils.parser(this).parseFragmentInput(html, context, this.baseUri());
        this.parentNode.addChildren(index, (Node[])nodes.toArray(new Node[0]));
    }

    public Node wrap(String html) {
        Validate.notEmpty(html);
        Element context = this.parentNode != null && this.parentNode instanceof Element ? (Element)this.parentNode : (this instanceof Element ? (Element)this : null);
        List<Node> wrapChildren = NodeUtils.parser(this).parseFragmentInput(html, context, this.baseUri());
        Node wrapNode = (Node)wrapChildren.get(0);
        if (!(wrapNode instanceof Element)) {
            return this;
        } else {
            Element wrap = (Element)wrapNode;
            Element deepest = this.getDeepChild(wrap);
            if (this.parentNode != null) {
                this.parentNode.replaceChild(this, wrap);
            }

            deepest.addChildren(new Node[]{this});
            if (wrapChildren.size() > 0) {
                for(int i = 0; i < wrapChildren.size(); ++i) {
                    Node remainder = (Node)wrapChildren.get(i);
                    if (wrap != remainder) {
                        if (remainder.parentNode != null) {
                            remainder.parentNode.removeChild(remainder);
                        }

                        wrap.after(remainder);
                    }
                }
            }

            return this;
        }
    }

    @Nullable
    public Node unwrap() {
        Validate.notNull(this.parentNode);
        List<Node> childNodes = this.ensureChildNodes();
        Node firstChild = childNodes.size() > 0 ? (Node)childNodes.get(0) : null;
        this.parentNode.addChildren(this.siblingIndex, this.childNodesAsArray());
        this.remove();
        return firstChild;
    }

    private Element getDeepChild(Element el) {
        List<Element> children = el.children();
        return children.size() > 0 ? this.getDeepChild((Element)children.get(0)) : el;
    }

    void nodelistChanged() {
    }

    public void replaceWith(Node in) {
        Validate.notNull(in);
        Validate.notNull(this.parentNode);
        this.parentNode.replaceChild(this, in);
    }

    protected void setParentNode(Node parentNode) {
        Validate.notNull(parentNode);
        if (this.parentNode != null) {
            this.parentNode.removeChild(this);
        }

        this.parentNode = parentNode;
    }

    protected void replaceChild(Node out, Node in) {
        Validate.isTrue(out.parentNode == this);
        Validate.notNull(in);
        if (in.parentNode != null) {
            in.parentNode.removeChild(in);
        }

        int index = out.siblingIndex;
        this.ensureChildNodes().set(index, in);
        in.parentNode = this;
        in.setSiblingIndex(index);
        out.parentNode = null;
    }

    protected void removeChild(Node out) {
        Validate.isTrue(out.parentNode == this);
        int index = out.siblingIndex;
        this.ensureChildNodes().remove(index);
        this.reindexChildren(index);
        out.parentNode = null;
    }

    protected void addChildren(Node... children) {
        List<Node> nodes = this.ensureChildNodes();
        Node[] var3 = children;
        int var4 = children.length;

        for(int var5 = 0; var5 < var4; ++var5) {
            Node child = var3[var5];
            this.reparentChild(child);
            nodes.add(child);
            child.setSiblingIndex(nodes.size() - 1);
        }

    }

    protected void addChildren(int index, Node... children) {
		...
	}

    protected void reparentChild(Node child) {
        child.setParentNode(this);
    }

    private void reindexChildren(int start) {
        if (this.childNodeSize() != 0) {
            List<Node> childNodes = this.ensureChildNodes();

            for(int i = start; i < childNodes.size(); ++i) {
                ((Node)childNodes.get(i)).setSiblingIndex(i);
            }

        }
    }

    public List<Node> siblingNodes() {
        if (this.parentNode == null) {
            return Collections.emptyList();
        } else {
            List<Node> nodes = this.parentNode.ensureChildNodes();
            List<Node> siblings = new ArrayList(nodes.size() - 1);
            Iterator var3 = nodes.iterator();

            while(var3.hasNext()) {
                Node node = (Node)var3.next();
                if (node != this) {
                    siblings.add(node);
                }
            }

            return siblings;
        }
    }

    @Nullable
    public Node nextSibling() {
        if (this.parentNode == null) {
            return null;
        } else {
            List<Node> siblings = this.parentNode.ensureChildNodes();
            int index = this.siblingIndex + 1;
            return siblings.size() > index ? (Node)siblings.get(index) : null;
        }
    }

    @Nullable
    public Node previousSibling() {
        if (this.parentNode == null) {
            return null;
        } else {
            return this.siblingIndex > 0 ? (Node)this.parentNode.ensureChildNodes().get(this.siblingIndex - 1) : null;
        }
    }

    public int siblingIndex() {
        return this.siblingIndex;
    }

    protected void setSiblingIndex(int siblingIndex) {
        this.siblingIndex = siblingIndex;
    }

    public Node traverse(NodeVisitor nodeVisitor) {
        Validate.notNull(nodeVisitor);
        NodeTraversor.traverse(nodeVisitor, this);
        return this;
    }

    public Node filter(NodeFilter nodeFilter) {
        Validate.notNull(nodeFilter);
        NodeTraversor.filter(nodeFilter, this);
        return this;
    }

    public String outerHtml() {
        StringBuilder accum = StringUtil.borrowBuilder();
        this.outerHtml(accum);
        return StringUtil.releaseBuilder(accum);
    }

    protected void outerHtml(Appendable accum) {
        NodeTraversor.traverse(new OuterHtmlVisitor(accum, NodeUtils.outputSettings(this)), this);
    }

    abstract void outerHtmlHead(Appendable var1, int var2, Document.OutputSettings var3) throws IOException;

    abstract void outerHtmlTail(Appendable var1, int var2, Document.OutputSettings var3) throws IOException;

    public <T extends Appendable> T html(T appendable) {
        this.outerHtml(appendable);
        return appendable;
    }

    public String toString() {
        return this.outerHtml();
    }

    protected void indent(Appendable accum, int depth, Document.OutputSettings out) throws IOException {
        accum.append('\n').append(StringUtil.padding(depth * out.indentAmount()));
    }

    public boolean equals(@Nullable Object o) {
        return this == o;
    }

    public int hashCode() {
        return super.hashCode();
    }

    public boolean hasSameValue(@Nullable Object o) {
        if (this == o) {
            return true;
        } else {
            return o != null && this.getClass() == o.getClass() ? this.outerHtml().equals(((Node)o).outerHtml()) : false;
        }
    }

    public Node clone() {
		...
	}

	...

org.jsoup.nodes.Element extends Node

org.jsoup.nodes.Document extends Element

应用场景

CASE : 解析 HTML文档 => 获得 Document 对象

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;

String html = "<html><head><title>First parse</title></head><body><p>Parsed HTML into a doc.</p></body></html>";
Document doc = Jsoup.parse(html);

CASE : 解析 HTML 片段 => 获得 Document 对象

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;

String html = "<div><p>Lorem ipsum.</p>";
Document doc = Jsoup.parseBodyFragment(html);
Element body = doc.body();

CASE : 解析 URL => 获得 Document 对象

org.jsoup.Connection connection = Jsoup.connect("http://example.com/");
Document doc = connection.get();//HTTP Method = GET
String title = doc.title();

还可以携带cookie等参数：(和Python的爬虫类似)

Document doc = Jsoup.connect("http://example.com")   
.data("query", "Java")   
.userAgent("Mozilla")   
.cookie("auth", "token")   
.timeout(3000)   
.post(); //HTTP Method = POST

CASE : 解析 HTML 本地文件 => 获得 Document 对象

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


/**
 * 提取文件里面的文本信息
 */
public static String openFile(String szFileName) {
    try {
        BufferedReader bis = new BufferedReader(new InputStreamReader(new FileInputStream(new File(szFileName)), ENCODE));
        String szContent = "";
        String szTemp;

        while ((szTemp = bis.readLine()) != null) {
            szContent += szTemp + "\n";
        }
        bis.close();
        return szContent;
    } catch (Exception e) {
        return "";
    }
}

X 参考文献

jsoup

https://jsoup.org/

https://mvnrepository.com/artifact/org.jsoup/jsoup/1.12.2

标签：Node,return,String,爬虫,parentNode,Jsoup,HTML,Document,public
From： https://www.cnblogs.com/johnnyzen/p/18449179

[网络爬虫] Jsoup : HTML 解析工具

1 概述

简介

主要特点

应用场景

竞品

2 使用指南

依赖引入

核心 API

org.jsoup.Jsoup

org.jsoup.nodes.Node

关键 API

源码

org.jsoup.nodes.Element extends Node

org.jsoup.nodes.Document extends Element

应用场景

CASE : 解析 HTML文档 => 获得 Document 对象

CASE : 解析 HTML 片段 => 获得 Document 对象

CASE : 解析 URL => 获得 Document 对象

CASE : 解析 HTML 本地文件 => 获得 Document 对象

X 参考文献

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