Java使用itext5实现生成多个PDF并合并

    /**
     * 根据id查询数据
     * @param id 数据id
     * @return
     */
    private map<string, string> queryentitydatabyid(string id) {
        //根据id查询
        box entity = boxservice.getbyid(id);

        map<string, string> data = new hashmap<string, string>();
        //显示内容
        //id
        data.put("id", entity.getjdkh());
        //动态生成当前时间的yymmddhh格式
        datetimeformatter formatter = datetimeformatter.ofpattern("yymmddhh");
        string currentdate = localdatetime.now().format(formatter);
        data.put("date", currentdate);

        //二维码内容
        data.put("imsi", entity.getimsi());
        data.put("imei", entity.getimei());

        string type = entity.gettype();
        if (type == null || type.isempty()) {
            type = "a";
        }
        data.put("type", type);
        return data;
    }

    //根据数据生成pdf
    private void generatepdffordata(map<string, string> data, bytearrayoutputstream outputstream) throws exception {
        // load the pdf template
        inputstream templatestream = getclass().getresourceasstream("/template/ddentitytemplate.pdf");
        pdfreader reader = new pdfreader(templatestream);
        pdfstamper stamper = new pdfstamper(reader, outputstream);

        acrofields form = stamper.getacrofields();
        string fontpath = file.separator + "font" + file.separator + "micosoftyh.ttf";
        basefont bfchinese = basefont.createfont(fontpath, basefont.identity_h, basefont.embedded);
        map<string, acrofields.item> fields = form.getfields();
        for (string k : fields.keyset()) {
            form.setfieldproperty(k, "textfont", bfchinese, null);
            form.setfieldproperty(k, "textsize", float.valueof("55"), null);
            form.setfieldproperty(k, "textstyle", com.itextpdf.text.font.bold, null);
            form.setfieldproperty(k, "textalign", element.align_middle, null);
        }
        //特殊文本框字体大小重置
        form.setfieldproperty("$serialnumber$", "textsize", float.valueof("40"), null);
        //标签内容
        //id
        form.setfield("$id$", data.get("id"));
        //日期
        form.setfield("$date$", data.get("date"));

        //二维码
        string qrcontent = string.format(
                        "id:%s\n" +
                        "imsi:%s\n" +
                        "imei:%s\n" +
                        "type:%s",
                data.get("id"), data.get("imsi"), data.get("imei"),data.get("type"));
        pdfcontentbyte cb = stamper.getovercontent(1);
        generateqrcode(qrcontent, cb);
        stamper.setformflattening(true);
        stamper.close();
        reader.close();
    }

    /**
     * 根据id批量生成pdf并合并
     * @param ids ids集合
     * @return 可直接访问的pdf流文件
     */
    @getmapping("/generatemergepdfstream")
    public responseentity<bytearrayresource> generatemergepdfstream(@requestparam string ids) {
        long starttime = system.currenttimemillis();
        system.out.println("开始生成pdf: " + starttime);
        try {
            string[] idarray = ids.split(",");
            bytearrayoutputstream mergedoutputstream = new bytearrayoutputstream();
            document mergeddocument = new document();
            pdfsmartcopy copy = new pdfsmartcopy(mergeddocument, mergedoutputstream);
            mergeddocument.open();

            for (string id : idarray) {
                map<string, string> data = queryentitydatabyid(id.trim());

                bytearrayoutputstream pdfoutputstream = new bytearrayoutputstream();
                generatepdffordata(data, pdfoutputstream);

                system.out.println("生成的pdf文件大小: " + pdfoutputstream.size());

                pdfreader reader = new pdfreader(new bytearrayinputstream(pdfoutputstream.tobytearray()));
                copy.adddocument(reader);
                reader.close();
                pdfoutputstream.close();
            }

            mergeddocument.close();

            bytearrayresource resource = new bytearrayresource(mergedoutputstream.tobytearray());

            httpheaders headers = new httpheaders();
            headers.add("content-disposition", "inline; filename=merged.pdf");

            long generationend = system.currenttimemillis();
            system.out.println("pdf生成与合并完成，总耗时: " + (generationend - starttime) + " 毫秒");

            return responseentity.ok()
                    .headers(headers)
                    .contenttype(mediatype.application_pdf)
                    .body(resource);

        } catch (exception e) {
            e.printstacktrace();
            return responseentity.status(500).build();
        }
    }

#访问jar包位置的同级files文件，可以直接通过http://ip:port/files下的文件名访问
spring.web.resources.static-locations=file:./files/

    /**
     * 生成合并的pdf文件保存到服务器下面
     * application.properties下面需要配置spring.web.resources.static-locations=file:./files/
     * jar包运行的文件夹目录
     * @param ids ids集合
     * @return 可直接访问的http://ip:port/*.pdf
     */
    @getmapping("/generateentitylogpdf")
    public responseentity generatemergesavepdf(@requestparam string ids, httpservletrequest request) {
        try {
            // 分割ids
            string[] idarray = ids.split(",");

            // 输出流
            bytearrayoutputstream mergedoutputstream = new bytearrayoutputstream();
            document mergeddocument = new document();
            pdfcopy copy = new pdfcopy(mergeddocument, mergedoutputstream);
            mergeddocument.open();

            for (string id : idarray) {
                //根据id查询pdf所需要数据
                map<string, string> data = queryentitydatabyid(id.trim());

                // 根据id生成pdf数据流
                bytearrayoutputstream pdfoutputstream = new bytearrayoutputstream();
                generatepdffordata(data, pdfoutputstream);

                // 将生成的pdf数据流
                pdfreader reader = new pdfreader(new bytearrayinputstream(pdfoutputstream.tobytearray()));
                copy.adddocument(reader);
                reader.close();
            }

            mergeddocument.close();

            //保存文件路径
            string currentdatedir = localdate.now().format(datetimeformatter.ofpattern("yyyymmdd"));
            // 获取运行目录下的 files 目录路径
            string filepath = system.getproperty("user.dir") + file.separator + "files" + file.separator + currentdatedir;
            file directory = new file(filepath);

            // 检查目录是否存在，不存在则创建
            if (!directory.exists()) {
                directory.mkdirs();
            }

            // 保存文件名
            random random = new random();
            int randomnumber = random.nextint(1000);
            string filename = system.currenttimemillis() + "_" + randomnumber + ".pdf";

            file file = new file(directory, filename);
            try (fileoutputstream fos = new fileoutputstream(file)) {
                fos.write(mergedoutputstream.tobytearray());
                fos.flush();
                system.out.println("文件保存成功：" + file.getabsolutepath());
            } catch (ioexception e) {
                e.printstacktrace();
            }
            //返回直接访问pdf的url
            string ip = request.getservername();
            int port = request.getserverport();
            string fileurl = "http://" + ip + ":" + port + "/" + currentdatedir + "/" + filename;
            return responseentity.ok(fileurl);
        } catch (exception e) {
            e.printstacktrace();
            return responseentity.status(500).build();
        }
    }