需求：
将后台的一堆数据，利用velocity模板将html格式生成pdf文件展示，通常在生成XX报告、XX公告场景下常用，毕竟pdf样式稳定，又可以下载。
velocity语法也特别简单，不会的可以看下/qiaodaima0/article/details/126158419?spm=1001..3001.5501
思路：
将文字内容生成pdf文件用itextpdf就可以很简单的完成，但是pdf一般要求特定的格式（比如报告类的就喜欢用固定的红头标题）或者一定的美观性，纯用后端渲染就不是很方便了，但是html渲染样式就很简单，两个结合就能比较简单生成美观的pdf。
环境：
springboot 2.7.2
jdk1.8
velocity 1.7
itextpdf
实操：
包目录
1、让前端小姐姐搞一个漂亮的html
注意：html里面的图片或js/css等其他的静态资源不允许用外部连接，图片就直接用base64码即可
我们弄一个简单带表格的html，如下：
<!DOCTYPE html><html><head><meta charset="UTF-8"/></head><body><div class="contianer"><div class="bg-img-container"></div><h1>模板pdf</h1><div class="flex-div"><p>表1</p></div><table border="1" cellSpacing="1"><tr><th>姓名</th><td colspan="3">$!{name}</td></tr><tr><th #if($!{gender}==1) class="blue" #else class="red" #end>性别</th><td colspan="3">#if($!{gender}==1)男#else女#end</td></tr><tr><th>出生日期</th><td>$!{birthDate}</td><th>联系方式</th><td>$!{phone}</td></tr></table><h1>双重For循环取值</h1><div class="flex-div"><p>表2</p></div><table border="1" cellSpacing="1"><tr><th>学历</th><th>学科</th><td class="gray-bg">分数</td></tr>#foreach($item in $eduList)<tr><th #set($len= $item.size+1) rowspan="$len">$item.name</th>#foreach($result in $item.itemList)<tr><td>$velocityCount、$result.subject</td><td #if($result.num > 60) class="green" #else class="red" #end>$result.num</td></tr>#end</tr>#end</table></div></body><style>.blue {color: #244385;margin-left: 30px;}.green {color: #52c41a;margin-left: 30px;}.red {color: #c1181e;margin-left: 30px;}.flex-div {margin: 30px 0 15px;display: flex;align-items: center;}.line {width: 540px;height: 0px;border: dashed 1px #edf0f5;}table {width: 700px;border-collapse: collapse;/*border-spacing: 0;*/border-left: 1px solid #edf0f5;border-top: 1px solid #edf0f5;}th, td {border-right: 1px solid #edf0f5;border-bottom: 1px solid #edf0f5;padding: 5px 15px;}h1 {text-align: center;font-family: 'Microsoft YaHei';line-height: 60px;letter-spacing: 8px;color: #244385;}p {font-family: 'Microsoft YaHei';font-size: 20px;font-weight: normal;color: #244385;margin: 0 16px;}th {background-color: rgba(0, 0, 0, 0.01);width: 90px;min-width: 90px;max-width: 90px;text-align: left;text-indent: 10px;font-family: 'Microsoft YaHei';font-size: 16px;font-weight: normal;font-stretch: normal;line-height: 48px;letter-spacing: 2px;color: #666666;}td {font-size: 16px;color: #000000;text-align: left;text-indent: 10px;padding-right: 20px;height: 50px;}table,tr, th, td {border: solid 1px #edf0f5;}.gray-bg {background-color: rgba(0, 0, 0, 0.01);}</style></html>
2、pom依赖
<?xml version="1.0" encoding="UTF-8"?><project xmlns="/POM/4.0.0" xmlns:xsi="/2001/XMLSchema-instance"xsi:schemaLocation="/POM/4.0.0 /xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.7.2</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.template.pdf</groupId><artifactId>template_pdf</artifactId><version>0.0.1-SNAPSHOT</version><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><!--工具类依赖--><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.7.19</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.76</version></dependency><!--pdf--><dependency><groupId>org.apache.velocity</groupId><artifactId>velocity</artifactId><version>1.7</version></dependency><dependency><groupId>com.itextpdf</groupId><artifactId>html2pdf</artifactId><version>4.0.3</version></dependency><dependency><groupId>com.itextpdf</groupId><artifactId>font-asian</artifactId><version>7.2.3</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>
3、PdfUtil工具类
import com.itextpdf.html2pdf.ConverterProperties;import com.itextpdf.html2pdf.HtmlConverter;import com.itextpdf.kernel.font.PdfFont;import com.itextpdf.kernel.font.PdfFontFactory;import com.itextpdf.kernel.geom.PageSize;import com.itextpdf.kernel.pdf.PdfDocument;import com.itextpdf.kernel.pdf.PdfWriter;import com.itextpdf.layout.font.FontProvider;import org.apache.velocity.Template;import org.apache.velocity.app.Velocity;import org.apache.velocity.context.Context;import org.apache.velocity.runtime.RuntimeConstants;import org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader;import java.io.OutputStream;import java.io.StringWriter;import java.nio.charset.StandardCharsets;/*** PDF工具** @author ppp* @date /8/5*/public class PdfUtil {static {// Velocity初始化Velocity.setProperty(RuntimeConstants.OUTPUT_ENCODING, StandardCharsets.UTF_8);Velocity.setProperty(RuntimeConstants.INPUT_ENCODING, StandardCharsets.UTF_8);Velocity.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");Velocity.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());Velocity.init();}/*** 据模板生成pfd格式文件** @param context上下文对象* @param templatepdf模板* @param outputStream 生成ofd文件输出流*/public static void pdfFile(Context context, String template, OutputStream outputStream) {try (PdfWriter pdfWriter = new PdfWriter(outputStream)) {PdfDocument pdfDocument = new PdfDocument(pdfWriter);pdfDocument.setDefaultPageSize(PageSize.A4);ConverterProperties properties = new ConverterProperties();FontProvider fontProvider = new FontProvider();// 字体设置，解决中文不显示问题PdfFont sysFont = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H");fontProvider.addFont(sysFont.getFontProgram(), "UniGB-UCS2-H");properties.setFontProvider(fontProvider);Template pfdTemplate = Velocity.getTemplate(template, "UTF-8");StringWriter writer = new StringWriter();pfdTemplate.merge(context, writer);HtmlConverter.convertToPdf(writer.toString(), pdfDocument, properties);pdfDocument.close();} catch (Exception e) {throw new RuntimeException("PFD文件生成失败", e);}}}
4、Controller接口测试
/*** PDF生成Controller* @author ppp* @date /8/4*/@Controller@RequestMapping("/velocity")public class PdfController {@RequestMapping("/getPdf")public void get(HttpServletResponse response){response.reset();response.setContentType("application/pdf");String filename = System.currentTimeMillis()+".pdf";response.addHeader("Content-Disposition", "inline; filename=" + URLUtil.encode(filename, CharsetUtil.CHARSET_UTF_8));VelocityContext context = new VelocityContext();context.put("name", "彭也行");context.put("gender", 1);context.put("birthDate", DateUtil.formatDateTime(new Date()));context.put("phone", "13666666666");List<Map<String, Object>> eduList = new ArrayList<>();// 小学Map<String, Object> primarySchoolMap = new HashMap<>();primarySchoolMap.put("name", "小学");List<Map<String, Object>> scoreList = new ArrayList<>();// 语文成绩Map<String, Object> chineseScore = new HashMap<>();chineseScore.put("subject", "语文");chineseScore.put("num", 60);// 数学成绩Map<String, Object> mathScore = new HashMap<>();mathScore.put("subject", "数学");mathScore.put("num", 99);scoreList.add(chineseScore);scoreList.add(mathScore);primarySchoolMap.put("itemList", scoreList);primarySchoolMap.put("size", scoreList.size());// 初中Map<String, Object> middleSchoolMap = new HashMap<>();middleSchoolMap.put("name", "初中");List<Map<String, Object>> middleScoreList = new ArrayList<>();// 语文成绩Map<String, Object> middleChineseScore = new HashMap<>();middleChineseScore.put("subject", "语文");middleChineseScore.put("num", 60);// 数学成绩Map<String, Object> middleMathScore = new HashMap<>();middleMathScore.put("subject", "数学");middleMathScore.put("num", 99);// 英语Map<String, Object> middleEnScore = new HashMap<>();middleEnScore.put("subject", "英语");middleEnScore.put("num", 55);middleScoreList.add(middleChineseScore);middleScoreList.add(middleMathScore);middleScoreList.add(middleEnScore);middleScoreList.add(middleEnScore);middleScoreList.add(middleEnScore);middleScoreList.add(middleEnScore);middleScoreList.add(middleEnScore);middleScoreList.add(middleEnScore);middleSchoolMap.put("itemList", middleScoreList);middleSchoolMap.put("size", middleScoreList.size());eduList.add(primarySchoolMap);eduList.add(middleSchoolMap);context.put("eduList", eduList);try(ServletOutputStream outputStream = response.getOutputStream()){PdfUtil.pdfFile(context, "demo.html", outputStream);}catch (Exception e){e.printStackTrace();}}}
5、效果
还是很好看的，用户访问连接就可以直接预览，也可以自己下载
