JSOUP指的是前端爬虫框架，对HTML网页的一系列操作包括信息的获取内容的修改等。
jsoup简单应用
1.三种加载HTML的方法
@Test
public void test1() throws IOException {
//从URL加载HTML
Document document = Jsoup.connect("http://www.guge.com").get();
String title = document.title();
//获取html中的标题
System.out.println("title :"+title);
//从字符串加载HTML
String html = "<html><head><title>First parse</title></head>"
+ "<body><p>Parsed HTML into a doc.</p></body></html>";
Document doc = Jsoup.parse(html);
title = doc.title();
System.out.println("title :"+title);
//从文件加载HTML
doc = Jsoup.parse(new File("d:\\file\\html\\index.html"),"utf-8");
title = doc.title();
System.out.println("title :"+title);
}
2.获取html中的head，body,url等信息
@Test
public void test2() throws IOException {
Document document = Jsoup.connect("http://www.guge.com").get();
String title = document.title();
System.out.println("title :"+title);
//获取html中的head
System.out.println(document.head());
//获取html中的body
//System.out.println(document.body());
//获取HTML页面中的所有链接
Elements links = document.select("a[href]");
for (Element link : links){
System.out.println("link : "+ link.attr("href"));
System.out.println("text :"+ link.text());
}
}
3.获取URL的地址信息
@Test
public void test3() throws IOException {
Document document = Jsoup.connect("https://passport.lagou.com").get();
System.out.println(document.head());
//获取URL的元信息
String description = document.select("meta[name=description]").get(0).attr("content");
System.out.println("Meta description : " + description);
String keywords = document.select("meta[name=keywords]").first().attr("content");
System.out.println("Meta keyword : " + keywords);
}
4.根据class名称获取表单
@Test
public void test4() throws IOException {
Document document = Jsoup.connect("https://passport.lagou.com/login/login.html?signature=8ECBCDF2B86061432B425A0B94FC863B&service=https%253A%252F%252Fwww.lagou.com%252F&action=login&serviceId=lagou&ts=1547711303033").get();
//获取拉勾网登入页面的body
//System.out.println(document.body());
//根据class名称获取表单
Elements formElement = document.getElementsByClass("form_body");
System.out.println(formElement.html());
//获取URL的元信息
for (Element inputElement : formElement) {
String placeholder = inputElement.getElementsByTag("input").attr("placeholder");
System.out.println(placeholder);
}
}
5.提取并打印表单参数
@Test
public void test5() throws IOException {
Document document = Jsoup.parse(new File("d:\\file\\html\\index.html"),"utf-8");
Element loginform = document.getElementById("registerform");
Elements inputElements = loginform.getElementsByTag("input");
for (Element inputElement : inputElements) {
String key = inputElement.attr("name");
String value = inputElement.attr("value");
System.out.println("Param name: "+key+" -- Param value: "+value);
}
}
6.设置元素的html内容
@Test
public void test6() throws IOException {
Document document = Jsoup.parse(new File("d:\\file\\html\\index.html"),"utf-8");
System.out.println(document.body());// <div id="div1"></div>
System.out.println("----------------");
Element div = document.select("div").first();
div.html("<p>Hello</p>"); // <div id="div1"><p>Hello</p></div>
div.prepend("<p>Fiest</p>"); //<div id="div1"><p>Fiest</p><p>Hello</p></div>
div.append("<p>Last</p>"); //<div id="div1"><p>Fiest</p><p>Hello</p><p>Last</p></div>
System.out.println(document.body());
System.out.println("------------------");
System.out.println(div.text());
System.out.println("-------------------");
//对元素包裹一个外部HTML内容
div.wrap("<div id=\"div2\"></div>"); //<div id="div2"><div id="div1"><p>Fiest</p><p>Hello</p><p>Last</p></div>
System.out.println(document.body());
}
7.设置元素的文本内容
@Test
public void test7() throws IOException {
Document document = Jsoup.parse(new File("d:\\file\\html\\index.html"),"utf-8");
System.out.println(document.body());// <div id="div1"></div>
System.out.println("-------------------");
Element div = document.select("div").first();
div.text("7 > 8 "); // <div id="div1">7 > 8 </div>
div.prepend("Fiest "); //<div id="div1">Fiest 7 > 8</div>
div.append("Last "); //<div id="div1">Fiest 7 > 8 Last</div>
System.out.println(document.body());
System.out.println("---------------");
System.out.println(div.text());
}
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