标签：document HTML text System Jsoup html println 解析 out

1.Jsoup（HTML解析）

https://blog.csdn.net/qq_26786441/article/details/106207828

2.Jsoup解析html

https://blog.csdn.net/m0_66144992/article/details/122329560

1、环境

首先导入jar包

<dependency>
    <groupId>org.jsoup</groupId>
    <artifactId>jsoup</artifactId>
    <version>1.11.3</version>
</dependency>
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.7</version>
</dependency>
<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.6</version>
</dependency>

然后准备一个用于解析的jsoup.html,放于webapp目录下

<html>
<head>
    <title>传智播客官网-一样的教育,不一样的品质</title>
</head>
<body>
<div class="city">
    <h3 id="city_bj">北京中心</h3>
    <fb:img src="/2018czgw/images/slogan.jpg" class="slogan"/>
    <div class="city_in">
        <div class="city_con" style="display: none;">
            <ul>
                <li id="test" class="class_a class_b">
                    <a href="http://www.itcast.cn" target="_blank">
                        <span class="s_name">北京</span>
                    </a>
                </li>
                <li>
                    <a href="http://sh.itcast.cn" target="_blank">
                        <span class="s_name">上海</span>
                    </a>
                </li>
                <li>
                    <a href="http://gz.itcast.cn" target="_blank">
                        <span abc="123" class="s_name">广州</span>
                    </a>
                </li>
                <ul>
                    <li>天津</li>
                </ul>
            </ul>
        </div>
    </div>
</div>
</body>
</html>

2、3种获取Dom方式

2.1解析url

@Test
public void testJsoupUrl() throws Exception {
    //解析url地址
    Document document = Jsoup.parse(new URL("http://www.itcast.cn/"), 1000);
    //获取title的内容
    Element title = document.getElementsByTag("title").first();
    System.out.println(title.text());
}

虽然使用Jsoup可以替代HttpClient直接发起请求解析数据，但是往往不会这样用，因为实际的开发过程中，需要使用到多线程，连接池，代理等等方式，而jsoup对这些的支持并不是很好，

所以我们一般把jsoup仅仅作为Html解析工具使用

2.2解析字符串

@Test
public void testJsoupString() throws IOException {
    //读取文件获取
    //String html = FileUtils.readFileToString(new File("D:\\jsoup.html"), "UTF-8");
    String html = IOUtils.toString(new FileInputStream("src/main/webapp/jsoup.html"), "UTF-8");
    //解析字符串
    Document document = Jsoup.parse(html);
    //获取title的内容
    Element title = document.getElementsByTag("title").first();
    System.out.println(title.text());
}

2.3直接解析文件

@Test
public void testJsoupHtml() throws IOException {
    //解析文件
    // Document document = Jsoup.parse(new File("D:\\jsoup.html"),"UTF-8");
    Document document = Jsoup.parse(new FileInputStream("src/main/webapp/jsoup.html"), "UTF-8", "");
    //获取title内容
    Element title = document.getElementsByTag("title").first();
    System.out.println(title.text());
}

3、解析Dom方法

3.1dom方式遍历文档，获取元素

@Test
public void testDoucment() throws IOException {
    String html = IOUtils.toString(new FileInputStream("src/main/webapp/jsoup.html"), "UTF-8");
    Document document = Jsoup.parse(html);

    //1.根据id查询元素getElementById
    Element element = document.getElementById("city_bj");
    System.out.println(element.text());

    //2.根据标签获取元素getElementsByTag
    element = document.getElementsByTag("title").first();
    System.out.println(element.text());

    //3.根据class获取元素getElementsByClass
    //element = document.getElementsByClass("class_a").last();
    // element = document.getElementsByClass("class_b").last();
    element = document.getElementsByClass("class_a class_b").last();
    System.out.println(element.text());

    //4.根据属性获取元素getElementsByAttribute
    //        element = document.getElementsByAttribute("abc").first();
    element = document.getElementsByAttributeValue("abc", "123").first();
    System.out.println(element.text());
}

3.2元素中获取数据

@Test
public void testData() throws Exception {
    String html = IOUtils.toString(new FileInputStream("src/main/webapp/jsoup.html"), "UTF-8");
    Document document = Jsoup.parse(html);
    Element element = document.getElementById("test");

    //1.从元素中获取id
    String id = element.id();
    System.out.println(id);
    //2.从元素中获取className
    String className = element.className();
    System.out.println(className);
    //3.从元素中获取属性的值attr
    id = element.attr("id");
    System.out.println(id);
    //4.从元素中获取所有属性attributes
    Attributes attributes = element.attributes();
    String s = attributes.toString();
    System.out.println(s);
    //5.从元素中获取文本内容text
    System.out.println(element.text());
}

3.3select，css查找

@Test
public void testSelector() throws IOException {
    String html = IOUtils.toString(new FileInputStream("src/main/webapp/jsoup.html"), "UTF-8");
    Document document = Jsoup.parse(html);
    //tagname: 通过标签查找元素，比如：span
    Elements elements = document.select("span");
    elements.forEach(element -> System.out.println(element.text()));

    //#id: 通过ID查找元素，比如：#city_bjj
    String text = document.select("#city_bj").text();

    //.class: 通过class名称
    text = document.select(".class_a").text();

    //[attribute]: 利用属性查找元素，比如：[abc]
    text = document.select("[abc]").text();

    //[attr=value]: 利用属性值来查找元素，比如：[class=s_name]
    text = document.select("[class=s_name]").text();
}

3.4select，css组合查找

 @Test
public void testSelectors() throws IOException {
    String html = IOUtils.toString(new FileInputStream("src/main/webapp/jsoup.html"), "UTF-8");
    Document document = Jsoup.parse(html);

    //el#id: 元素+ID，比如： h3#city_bj
    String str = document.select("h3#city_bj").text();
    System.out.println(str);

    //el.class: 元素+class，比如： li.class_a
    System.out.println(document.select("li.class_a").text());

    //el[attr]: 元素+属性名，比如： span[abc]
    System.out.println(document.select("span[abc]").text());

    //任意组合: 比如：span[abc].s_name
    System.out.println(document.select("span[abc].s_name").text());

    //ancestor child: 查找某个元素下子元素，比如：.city_con li 查找"city_con"下的所有li
    System.out.println(document.select(".city_con li").text());

    //parent > child: 查找某个父元素下的直接子元素，比如：
    //.city_con > ul > li 查找city_con第一级（直接子元素）的ul，再找所有ul下的第一级li
    System.out.println(document.select(".city_con > ul > li").text());

    //parent > *: 查找某个父元素下所有直接子元素
    System.out.println(document.select(".city_con > *").text());

}

标签：document,HTML,text,System,Jsoup,html,println,解析,out
From： https://www.cnblogs.com/kelelipeng/p/17329025.html

Jsoup（HTML解析）