${t.name}
${t.age}
${t.sex}
|
优势:不用接口做任何支持,提供了接口数据就行
劣势:前端是小程序,需要给页面换成h5,在渲染完页面转换为图片的时候有延迟,用户体感不好,并且需要页面完整展示数据并能带有滚动条,否则生成的图片数据缺失
所以想其它方案
优势:前端只管拿到图片数据展示,无延迟,用户体感好
劣势:项目没有相关实现,需要去探索
org.springframework.boot
spring-boot-starter-freemarker
2.2.9.RELEASE
org.xhtmlrenderer
flying-saucer-core
9.1.22
ftl其实就是html,但是填充数据相关的标签需要特定的标签,有其他需求的可以百度ftl标签用法
Document
班级:${name}
<#list mapList as t>
${t.name}
${t.age}
${t.sex}
#list>
可以看到在html2ImgBase64方法中有一部分代码是我给图片存在本地目录中,返回的是imgbase64,这个看个人需求看是需要图片还是base64自行处理
package com.nuoyi.ftl.util;
import freemarker.template.Configuration;
import freemarker.template.Template;
import lombok.extern.slf4j.Slf4j;
import org.w3c.dom.Document;
import org.xhtmlrenderer.layout.SharedContext;
import org.xhtmlrenderer.swing.Java2DRenderer;
import javax.imageio.ImageIO;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
/**
* @description 工具类
*/
@Slf4j
public class FreemarkerUtil {
private static Configuration config = null;
/**
* 初始化获取html模板
*/
static {
config = new Configuration(Configuration.VERSION_2_3_20);
config.setDefaultEncoding("UTF-8");
try {
config.setClassForTemplateLoading(FreemarkerUtil.class, "/templates");
} catch (Exception e) {
e.printStackTrace();
log.error(e.toString());
}
}
/**
* 把BufferedImage 图片转base64
*
* @param bufferedImage
* @return
* @throws Exception
*/
private static String bufferedImageToBase64(BufferedImage bufferedImage) throws Exception {
String png_base64;//转换成base64串
//io流
try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
ImageIO.write(bufferedImage, "png", baos);//写入流中
byte[] bytes = baos.toByteArray();//转换成字节
png_base64 = Base64.getEncoder().encodeToString(bytes);
png_base64 = png_base64.replaceAll("\n", "").replaceAll("\r", "");//删除 \r\n
}
return "data:image/jpg;base64," + png_base64;
}
/**
* 将html转成base64字节
*
* @param html
* @param width
* @param height
* @return
* @throws Exception
*/
public static String html2ImgBase64(String html, int width, int height) throws Exception {
byte[] bytes = html.getBytes();
BufferedImage img;
try (ByteArrayInputStream bin = new ByteArrayInputStream(bytes)) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(bin);
Java2DRenderer renderer = new Java2DRenderer(document, width, height);
SharedContext sharedContext = renderer.getSharedContext();
sharedContext.setDotsPerPixel(3);
sharedContext.setDPI(523);
img = renderer.getImage();
String imgName = Thread.currentThread().getContextClassLoader().getResource("").getPath() + "test.jpg";
System.out.println("输出地址:" + imgName);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
ImageIO.write(img, "jpg", new FileOutputStream(imgName));
}
return bufferedImageToBase64(img);
}
/**
* 将html转成 图片
*
* @param html
* @param width
* @param height
* @return
* @throws Exception
*/
public static BufferedImage html2Img(String html, int width, int height) throws Exception {
byte[] bytes = html.getBytes();
BufferedImage img;
//转BufferedImage
try (ByteArrayInputStream bin = new ByteArrayInputStream(bytes)) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(bin);
Java2DRenderer renderer = new Java2DRenderer(document, width, height);
SharedContext sharedContext = renderer.getSharedContext();
sharedContext.setDotsPerPixel(3);
sharedContext.setDPI(523);
//字体
Font simsun = getSIMSUN(Font.BOLD, 24);
sharedContext.setFontMapping("simsun", simsun);//这样设置字体无效
Map map = new HashMap<>();//设置参数
map.put(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
map.put(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
map.put(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
map.put(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
map.put(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
map.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
map.put(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
map.put(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
map.put(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
renderer.setRenderingHints(map);
img = renderer.getImage();
}
return img;
}
/**
* 获取模板数据
*
* @param template
* @param params
* @return
* @throws Exception
*/
public static String generate(String template, Map params) throws Exception {
Template tp = config.getTemplate(template);
tp.setEncoding("UTF-8");
StringWriter stringWriter = new StringWriter();
String htmlStr;
try {
tp.process(params, stringWriter);
htmlStr = stringWriter.toString();
stringWriter.flush();
} finally {
stringWriter.close();
}
return htmlStr;
}
/**
* 宋体
*
* @param style Font.BOLD
* @param size 24
*/
public static Font getSIMSUN(int style, float size) {
Font font = null;
//获取字体流
InputStream simsunFontFile = FreemarkerUtil.class.getResourceAsStream("/fonts/simsun.ttc");
try {
//创建字体
font = Font.createFont(Font.PLAIN, simsunFontFile).deriveFont(style, size);
} catch (FontFormatException e) {
log.error("", e);
} catch (IOException e) {
font = new Font("宋体", Font.BOLD, 6);
log.error("", e);
}
return font;
}
}
我这里是写了个单元测试进行调试,在方法中我给图片的地址和base64都打印出来了
package com.nuoyi.ftl;
import cn.hutool.core.lang.hash.Hash;
import com.nuoyi.ftl.bean.User;
import com.nuoyi.ftl.util.FreemarkerUtil;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@SpringBootTest(classes = App.class)
@Slf4j
public class HtmlToImgTest {
@Test
public void ftiToHtmlToImg() throws Exception{
Map mp = new HashMap<>();
mp.put("name", "101班");
List list = new ArrayList<>();
for (int i = 1; i < 4; i++) {
list.add(new User("我是"+i,i*3,"男"));
}
mp.put("mapList",list);
String html = FreemarkerUtil.generate("test.ftl", mp);
String s = FreemarkerUtil.html2ImgBase64(html, 1000, -1);
System.out.println(s);
}
}
具体代码移步 https://download.csdn.net/download/qq_41973632/87895892
服务器中生成的图片字体乱码异常等已解决移步springboot通过ftl模板动态生成图片字体异常加载字体文件处理