使用技术
itext.jar : 将byte文件输入流转换为图片,pdf等
html2canvas.js :将html页面区域截图为base64编码的图片资源
java+js
1. 准备资源
itext.jar
www.baidu.com
html2canvas.js
www.baidu.com
2.前端代码:
//进行截图操作,document.querySelector("body") 为要截图的区域 function test() { html2canvas(document.querySelector("body"), { onrendered: function (canvas) { var dataUrl = canvas.toDataURL('image/png'); var formData = new FormData(); //模拟表单对象 formData.append("imgData", convertBase64UrlToBlob(dataUrl)); //写入数据 var xhr = new XMLHttpRequest(); //数据传输方法 xhr.open("POST", "http://localhost:8080/pdf"); //配置传输方式及地址 xhr.send(formData); xhr.onreadystatechange = function () { //回调函数 }; } }); } //格式化图片base64编码转换为byte文件流 function convertBase64UrlToBlob(urlData){ //去掉url的头,并转换为byte var bytes=window.atob(urlData.split(',')[1]); //处理异常,将ascii码小于0的转换为大于0 var ab = new ArrayBuffer(bytes.length); var ia = new Uint8Array(ab); for (var s = 0;s<bytes.length;s++){ ia[s] = bytes.charCodeAt(s); } return new Blob( [ab] , {type : 'image/png'}); } <body onclick="test()">//调用截图方法即可
3.后端代码:
@RequestMapping(value = "/pdf",method = RequestMethod.POST) public void test(MultipartHttpServletRequest request, HttpServletResponse response) throws IOException { String filePath = "D:\\blog\\exportPdf2.pdf"; String imagePath = "D:\\blog\\exportImg2.png"; Document document = new Document(); try{ Map getMap = request.getFileMap(); MultipartFile mfile = (MultipartFile) getMap.get("imgData"); //获取数据 InputStream file = mfile.getInputStream(); byte[] fileByte = FileCopyUtils.copyToByteArray(file); FileImageOutputStream imageOutput = new FileImageOutputStream(new File(imagePath));//打开输入流 imageOutput.write(fileByte, 0, fileByte.length);//生成本地图片文件 imageOutput.close(); PdfWriter.getInstance(document, new FileOutputStream(filePath)); //itextpdf文件 document.open(); document.add(new Paragraph("JUST TEST ...")); Image image = Image.getInstance(imagePath); //itext-pdf-image float heigth = image.getHeight(); float width = image.getWidth(); int percent = getPercent2(heigth, width); //按比例缩小图片 image.setAlignment(Image.MIDDLE); image.scalePercent(percent+3); document.add(image); document.close(); }catch (DocumentException de) { System.err.println(de.getMessage()); } catch (Exception e) { e.printStackTrace(); } } private static int getPercent2(float h, float w) { int p = 0; float p2 = 0.0f; p2 = 530 / w * 100; p = Math.round(p2); return p; }
4 包名
import com.itextpdf.text.Document; import com.itextpdf.text.DocumentException; import com.itextpdf.text.Image; import com.itextpdf.text.Paragraph; import com.itextpdf.text.pdf.PdfWriter; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.stereotype.Controller; import org.springframework.util.FileCopyUtils; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.multipart.MultipartFile; import org.springframework.web.multipart.MultipartHttpServletRequest; import javax.imageio.stream.FileImageOutputStream; import javax.servlet.http.HttpServletResponse; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.Map;
4 前端截图,访问后端接口,保存截图文件到本地为pdf或者其他格式的文件。
有兴趣的同学可以把后端改为下载文件到本地
5 项目源码地址
https://github.com/zhangjy520/learn_java/tree/master/boot
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