<!-- html生成图片--><dependency><groupId>com.github.xuwei-k</groupId><artifactId>html2image</artifactId><version>0.1.0</version></dependency>

生成一个ftl的html模板，就像利用freemarker生成word一样。然后替换模板的内容，这些就不在写了。可参考freemarker生成word文档
这里我转化的图片后缀用的是png,因为jpg下出来带背景颜色。由于时间原因没在研究

模板替换好后使用html2image将html转化为图片

html2image相关方法：
loadUrl(url) - Loads HTML from URL object or URL string. (从url载入html)
loadHtml(html) - Loads HTML source. (载入本地html)
saveAsImage(file) - Save loaded HTML as image. (以图片形式保存html)
saveAsHtmlWithMap(file, imageUrl) - Creates an HTML file containing client-side image-map

自定义utils

FreemarkerUtils jar 项目

import freemarker.template.Template;
import freemarker.template.TemplateException;
import freemarker.template.TemplateExceptionHandler;
import gui.ava.html.image.generator.HtmlImageGenerator;
import freemarker.template.Configuration;import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.Map;public class FreemarkerUtils {private static String getTemplate(String template, Map<String, Object> map, String filePath, String fileName) throws IOException, TemplateException {@SuppressWarnings("deprecation")Configuration cfg = new Configuration();
//        String templatePath = FreemarkerUtils.class.getResource("/").getPath() + "/ftl"; windows 上
//        cfg.setDirectoryForTemplateLoading(new File(templatePath));cfg.setClassForTemplateLoading(FreemarkerUtils.class, "/ftl/");cfg.setDefaultEncoding("UTF-8");cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);cfg.setLogTemplateExceptions(false);Template temp = cfg.getTemplate(template);StringWriter stringWriter = new StringWriter();temp.process(map, stringWriter);stringWriter.flush();stringWriter.close();return stringWriter.getBuffer().toString();}public static void turnImage(String template, Map<String, Object> map, String filePath, String fileName, HttpServletResponse response) throws Exception {String html = getTemplate(template, map, filePath, fileName);HtmlImageGenerator imageGenerator = new HtmlImageGenerator();try {imageGenerator.loadHtml(html);Thread.sleep(500);//加入睡眠时间给充分的转化图片时间imageGenerator.getBufferedImage();Thread.sleep(500);imageGenerator.saveAsImage(filePath + File.separator + fileName);} catch (Exception e) {e.printStackTrace();throw new RuntimeException("将HTML文件转换成图片异常");}}}

FreemarkerUtils war 项目

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import freemarker.template.TemplateExceptionHandler;
import gui.ava.html.image.generator.HtmlImageGenerator;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.util.Map;public class FreemarkerUtils {private static String getTemplate(HttpServletRequest request, String template, Map<String, Object> map, String filePath, String fileName) throws IOException, TemplateException {@SuppressWarnings("deprecation")Configuration cfg = new Configuration();
//        String templatePath = FreemarkerUtils.class.getResource("/").getPath() + "/ftl";
//        cfg.setDirectoryForTemplateLoading(new File(templatePath));cfg.setServletContextForTemplateLoading(request.getServletContext(), "/ftl");cfg.setDefaultEncoding("UTF-8");cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);cfg.setLogTemplateExceptions(false);Template temp = cfg.getTemplate(template);StringWriter stringWriter = new StringWriter();temp.process(map, stringWriter);stringWriter.flush();stringWriter.close();return stringWriter.getBuffer().toString();}public static void turnImage(HttpServletRequest request, String template, Map<String, Object> map, String filePath, String fileName, HttpServletResponse response) throws Exception {String html = getTemplate(request, template, map, filePath, fileName);HtmlImageGenerator imageGenerator = new HtmlImageGenerator();try {imageGenerator.loadHtml(html);Thread.sleep(500);imageGenerator.getBufferedImage();Thread.sleep(500);imageGenerator.saveAsImage(filePath + File.separator + fileName);} catch (Exception e) {e.printStackTrace();throw new RuntimeException("将HTML文件转换成图片异常");}}

实际应用
前后分离项目返回base64字符串，前端处理
转base64用的包org.apache.commons.codec.binary;

			String fileName = fileName + customerInfoId + ".png";File file = null;try {FreemarkerUtils.turnImage("drawImgTemplate.ftl", map, filePath, fileName, response);// 通过文件路径获得File对象(假如此路径中有一个download.pdf文件)file = new File(filePath + File.separator + fileName);return file2Base64(file);} catch (Exception e) {logger.error("图纸下载图片失败", e);} finally {if (file != null) {file.delete();}}

private String file2Base64(File file) {if (file == null) {return null;}String base64 = null;FileInputStream fin = null;try {fin = new FileInputStream(file);byte[] buff = new byte[fin.available()];fin.read(buff);base64 = Base64.encodeBase64String(buff);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {if (fin != null) {try {fin.close();} catch (IOException e) {e.printStackTrace();}}}return base64;}

war项目：

 			String fileName = fileName + customer.getId() + ".png";try {FreemarkerUtils.turnImage(request, "drawImgTemplate.ftl", map, filePath, fileName, response);DownloadUtils.fileDownload(response, filePath, fileName);} catch (Exception e) {logger.error("图纸下载图片失败", e);} finally {File file = new File(filePath + fileName);if (file != null) {file.delete();}}

这里都别忘了删除存在我们项目下的图片

问题

如果放在liunx上，中文字体乱码，因为linux没有该字体，服务器放上该字体后即可
写的有点乱，就是记录下自己遇到的。