java将html转为pdf

项目采用springboot，由于是后端导出pdf，所以用thymeleaf作为页面，后端请求页面，获取渲染后的html字符串，再导出为pdf

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13</version>
</dependency>
<dependency>
    <groupId>org.xhtmlrenderer</groupId>
    <artifactId>flying-saucer-pdf-itext5</artifactId>
    <version>9.0.3</version>
</dependency>

逻辑代码

String htmlUrl = "访问的页面";
log.info("页面路径：{}", htmlUrl);
String html = OkHttpUtil.sendGet(htmlUrl);
String htmlContent = html.replace("<!DOCTYPE html>", "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">")
        .replace("<html lang=\"en\" xmlns:th=\"http://www.thymeleaf.org\">", "<html lang=\"en\" xmlns=\"http://www.w3.org/1999/xhtml\">");
log.info("html内容：\n{}", htmlContent);
File pdf = FileUtil.createTempFile(id + ".pdf");
HtmPdfUtil.html2pdf(htmlContent, pdf);

okhttp封装
注意，这里要将thymeleaf的部分标签替换为导出pdf支持的那种

thymeleaf标签

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">

生成pdf需要的标签

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

要支持中文html中设置<body style="font-family: SimSun;">

导出pdf工具

import com.itextpdf.text.pdf.BaseFont;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.io.ClassPathResource;
import org.xhtmlrenderer.pdf.ITextFontResolver;
import org.xhtmlrenderer.pdf.ITextRenderer;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
@Slf4j
public class HtmPdfUtil { 
    /** * 将HTML转成PDF格式的文件。html文件的格式比较严格 * * @param htmlContent * @param pdfFile * @throws Exception */
    public static void html2pdf(String htmlContent, File pdfFile) throws Exception { 
        OutputStream os = new FileOutputStream(pdfFile);
        ITextRenderer renderer = new ITextRenderer();
        renderer.setDocumentFromString(htmlContent);
        // 中文
        ITextFontResolver fontResolver = renderer.getFontResolver();
        ClassPathResource resource = new ClassPathResource("font/simsun.ttc");
        fontResolver.addFont(resource.getURL().toString(), BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
        renderer.layout();
        renderer.createPDF(os);
        os.close();
    }
}