用Spring MVC和Freemarker实现导出PDF

网上已经有比较多的例子，但是很多都是简单的 demo，而且有很多隐藏的问题，本人再次写一个完整的demo：

Spring MVC部分：

            response.reset();            response.setContentType("application/pdf;charset=utf-8");            fileName =  encodeFilename(request, fileName);            response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".pdf");            OutputStream rtnos = response.getOutputStream();            String htmlStr = HtmlGenerator.generate("sample.ftl", resultMap);            String imgWidth = "width=\"450\"";            String imgHeight = "height=\"300\"";            htmlStr = htmlStr.replaceAll("width=\"(.*?)\"", imgWidth).replaceAll("height=\"(.*?)\"", imgHeight);            logger.debug("===htmlStr===" + StringEscapeUtils.unescapeHtml(htmlStr));            PdfGenerator.generate(StringEscapeUtils.unescapeHtml(htmlStr).replaceAll("&", "&"), rtnos);            return null;

通过Freemarker模板生成html：

import java.io.BufferedWriter;  import java.io.StringWriter;  import java.util.Map;  import freemarker.template.Configuration;  import freemarker.template.Template;    public class HtmlGenerator {            /**      * Generate html string.      *       * @param template   the name of freemarker teamlate.      * @param variables  the data of teamlate.      * @return htmlStr      * @throws Exception      */      public static String generate(String template, Map<String,Object> variables) throws Exception{          Configuration config = FreemarkerConfiguration.getConfiguation();          config.setDefaultEncoding("UTF-8");        Template tp = config.getTemplate(template);          StringWriter stringWriter = new StringWriter();            BufferedWriter writer = new BufferedWriter(stringWriter);            tp.setEncoding("UTF-8");            tp.process(variables, writer);            String htmlStr = stringWriter.toString();          writer.flush();            writer.close();          return htmlStr;      }    }  

html转PDF：

import java.io.ByteArrayInputStream;import java.io.OutputStream;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import org.w3c.dom.Document;import org.xhtmlrenderer.pdf.ITextRenderer;public class PdfGenerator {    /**     * Output a pdf to the specified outputstream     *      * @param htmlStr the htmlstr     * @param out the specified outputstream     * @throws Exception     */    public static void generate(String htmlStr, OutputStream out) throws Exception {        DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();        Document doc = builder.parse(new ByteArrayInputStream(htmlStr.getBytes()));        ITextRenderer renderer = new ITextRenderer();        renderer.setDocument(doc, null);        renderer.layout();        renderer.createPDF(out);        out.flush();        out.close();    }}

sample.ftl(片段):

<#list data as note>    <li data-id="12" data-nodetime="${(note.nodeTime)!}" data-totaltime="${(note.totalTime)!}" data-nodename="${(note.nodeName)!}" data-imgs="${(note.imgsStr)!}" data-content="${(note.content)!}">        <div class="p-notelist-cite-wrap">            <<#if note.reference == "video">a<#else>span</#if> class="p-notelist-cite" href="${(note.subjectUrl)!}">                引用<i <#if note.reference == "video">class="i-icon i-icon-paly "<#else>class="i-icon i-icon-note "</#if>></i>${(note.nodeName)!}                <span class="p-time"> ${(note.nodeTime)!}／${(note.totalTime)!} </span> <#if note.reference == "video"><b>提纲</b></#if>            </<#if note.reference == "video">a<#else>span</#if>>            <div class="p-cite-content">                    <div class="p-cite-content-wrap">                    <div class="i-subject-content">                    <div class="subject subject-choice">    <div class="stem">        <span class="type">[单选]</span>        <span class="use-number"></span>        <p>A是老王</p><img src="http://kaoshi.neibu.koolearn.com/upload/image/1430791311563.png"></img>        <p>B是老张</p>        <p>谁是凶手</p>    </div>    <div class="answer">        <ul>            <li>                <span data-id="0" class="number">A</span>                <span class="content">A是凶手</span>            </li>            <li>                <span data-id="1" class="number">B</span>                <span class="content">B是凶手</span>            </li>        </ul>    </div></div></div></div>                    <a href="/project/teach/1.x/demo/apply/searchResult.html" target="_blank" class="p-view"><i class="i-icon i-icon-edit-hover"></i>在做题记录中查看</a>                </div>        </div>        <div class="p-note-content">            <span>${(note.content)!}</span>            <#if note.imgs??>                <#list note.imgs as img>                    <img src="${(img)!}" alt=""></img>            </#list>            </#if>        </div>        <div class="p-note-bottom">            <i class="i-icon i-icon-notemark"></i><span class="p-note-mark">${(note.mark)!}</span>            <div class="p-note-operate">                <span>${(note.time)!}</span>            </div>        </div>    </li></#list>