利用java实现一个图片转PDF文件工具
- 王林转载
- 2020-08-27 16:05:233636浏览
出于某些需求需要将一张简单的图片转换为PDF的文件格式，因此自己动手写了一个图片转换PDF的系统，现在将该系统分享在这里，供大家参考。
（学习视频推荐：java课程）
具体代码：
引入依赖：
<!--该项目以SpringBoot为基础搭建-->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
<relativePath/>
</parent>
<dependencies>
<!--SpringMVC的依赖，方便我们可以获取前端传递过来的文件信息-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--ITextPdf，操作PDF文件的工具类-->
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>5.4.2</version>
</dependency>
</dependencies>前端页面：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>图片转换Pdf</title>
<style>
.submitButton {
margin-top: 20px;
margin-left: 150px;
background-color: #e37e10;
border-radius: 10px;
border: 1px solid #ff8300;
}
</style>
</head>
<body>
<div style="text-align: center">
<h1>图片转换pdf工具</h1>
<form action="/pdf/image/to" enctype="multipart/form-data" method="post" onsubmit="return allowFileType()">
<input type="file" id="file" name="file" placeholder="请选择图片" onchange="allowFileType()" style="border: 1px solid black;"><br>
<input type="submit" value="一键转换pdf文件">
</form>
</div>
</body>
<script>
function allowFileType() {
let file = document.getElementById("file").files[0];
let fileName = file.name;
console.log(fileName)
let fileSize = file.size;
console.log(fileSize)
let suffix = fileName.substring(fileName.lastIndexOf("."),fileName.length);
if('.jpg' != suffix && '.png' != suffix) {
alert("目前只允许传入.jpg或者.png格式的图片！");
return false;
}
if(fileSize > 2*1024*1024) {
alert("上传图片不允许超过2MB!");
return false;
}
return true;
}
</script>
</html>（推荐教程：java入门教程）
控制层接口
package com.hrp.controller;
import com.hrp.util.PdfUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
/**
* @description: 用于处理Pdf相关的请求
*/
@Controller
@RequestMapping("pdf")
public class PdfController {
@PostMapping("image/to")
public void imageToPdf(@RequestParam("file") MultipartFile file,HttpServletResponse response) throws Exception{
PdfUtils.imageToPdf(file,response);
}
}PDF工具类
package com.hrp.util;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Image;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.pdf.PdfWriter;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
/**
* @description: pdf相关的工具类
*/
@Component
public class PdfUtils {
/**
* 图片转换PDF的公共接口
*
* @param file SpringMVC获取的图片文件
* @param response HttpServletResponse
* @throws IOException IO异常
* @throws DocumentException PDF文档异常
*/
public static void imageToPdf(MultipartFile file, HttpServletResponse response) throws IOException, DocumentException {
File pdfFile = generatePdfFile(file);
downloadPdfFile(pdfFile, response);
}
/**
* 将图片转换为PDF文件
*
* @param file SpringMVC获取的图片文件
* @return PDF文件
* @throws IOException IO异常
* @throws DocumentException PDF文档异常
*/
private static File generatePdfFile(MultipartFile file) throws IOException, DocumentException {
String fileName = file.getOriginalFilename();
String pdfFileName = fileName.substring(0, fileName.lastIndexOf(".")) + ".pdf";
Document doc = new Document(PageSize.A4, 20, 20, 20, 20);
PdfWriter.getInstance(doc, new FileOutputStream(pdfFileName));
doc.open();
doc.newPage();
Image image = Image.getInstance(file.getBytes());
float height = image.getHeight();
float width = image.getWidth();
int percent = getPercent(height, width);
image.setAlignment(Image.MIDDLE);
image.scalePercent(percent);
doc.add(image);
doc.close();
File pdfFile = new File(pdfFileName);
return pdfFile;
}
/**
*
* 用于下载PDF文件
*
* @param pdfFile PDF文件
* @param response HttpServletResponse
* @throws IOException IO异常
*/
private static void downloadPdfFile(File pdfFile, HttpServletResponse response) throws IOException {
FileInputStream fis = new FileInputStream(pdfFile);
byte[] bytes = new byte[fis.available()];
fis.read(bytes);
fis.close();
response.reset();
response.setHeader("Content-Type", "application/pdf");
response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(pdfFile.getName(), "UTF-8"));
OutputStream out = response.getOutputStream();
out.write(bytes);
out.flush();
out.close();
}
/**
* 等比压缩，获取压缩百分比
*
* @param height 图片的高度
* @param weight 图片的宽度
* @return 压缩百分比
*/
private static int getPercent(float height, float weight) {
float percent = 0.0F;
if (height > weight) {
percent = PageSize.A4.getHeight() / height * 100;
} else {
percent = PageSize.A4.getWidth() / weight * 100;
}
return Math.round(percent);
}
}实现效果：
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