html头部里面的css嵌入body里面

<dependency>
    <groupId>org.jsoup</groupId>
    <artifactId>jsoup</artifactId>
    <version>1.12.1</version>
</dependency>

import com.itextpdf.html2pdf.jsoup.Jsoup;
import com.itextpdf.html2pdf.jsoup.nodes.Element;
import com.itextpdf.html2pdf.jsoup.select.Elements;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author: 木杉
 * @email: 819236727@qq.com
 * @Date: 2019/7/23 9:01
 * @describe:
 */
public class Test {
    public static void main(String[] args) throws Exception{

        com.itextpdf.html2pdf.jsoup.nodes.Document doc = Jsoup.parse("要进行转换的html内容");
        String allcss = doc.getElementsByTag("style").html();
        Map<String, String> styleMap = new HashMap<>();
        Pattern pattern = Pattern.compile("\\.(\\w+)\\{(?s)(.+?)\\}");
        Matcher matcher = pattern.matcher(allcss);
        while (matcher.find()) {
            styleMap.put(matcher.group(1), matcher.group(2));
        }

        Elements anyClass = doc.getElementsByAttribute("class");
        for (Element element : anyClass) {
            String aClass = element.attr("class");
            String[] classStrs = (aClass.split(" "));
            for (String classStr : classStrs) {
                element.attr("style", element.attr("style") + styleMap.get(classStr));
            }
            element.removeAttr("class");
        }

        doc.getElementsByTag("style").remove();
        String html =  doc.toString();;
    }
}