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标题:
Java实现PDF文件转换为图片
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作者:
专注的一批
时间:
2020-9-4 10:33
标题:
Java实现PDF文件转换为图片
引入依赖
----
```xml
<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>
<!--icepdf，用来将pdf文件转换为图片的依赖-->
<dependency>
<groupId>org.icepdf.os</groupId>
<artifactId>icepdf-core</artifactId>
<version>6.2.2</version>
</dependency>
</dependencies>
```
前端页面
----
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>PDf转换图片</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>PDF转换图片工具</h1>
<form action="/pdf/to/image" enctype="multipart/form-data" method="post" onsubmit="return allowFileType()">
<input type="file" id="file" name="file" placeholder="请选择PDF文件" onchange="allowFileType()" style="border: 1px solid black;"><br>
<input type="submit" value="一键转换图片" class="submitButton">
</form>
</div>
</body>
<script>
function allowFileType() {
let file = document.getElementById("file").files[0];
let fileName = file.name;
let suffix = fileName.substring(fileName.lastIndexOf("."),fileName.length).toLowerCase();
if('.pdf' != suffix) {
alert("只允许传入PDF格式的文件！");
return false;
}
return true;
}
</script>
</html>
```
控制层接口
-----
```java
package com.hrp.controller;
import com.hrp.util.ImageUtils;
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("to/image")
public void pdfToImage(@RequestParam("file") MultipartFile file,HttpServletResponse response) throws Exception{
ImageUtils.pdfToImage(file,response);
}
}
```
Image工具类
--------
外汇常见问题https://www.kaifx.cn/lists/question/
```java
package com.hrp.util;
import org.icepdf.core.pobjects.Document;
import org.icepdf.core.pobjects.Page;
import org.icepdf.core.util.GraphicsRenderingHints;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
/**
* @description: PDF转换为图片的工具类
*/
@Component
public class ImageUtils {
/**
* 图片文件格式
*/
public static final String FORMAT_NAME = "png";
/**
* 图片文件后缀名
*/
public static final String PNG_SUFFIX = ".png";
/**
* 压缩文件后缀名
*/
public static final String ZIP_SUFFIX = ".zip";
/**
* 对外的开放接口，用于将PDF文件转换为图片文件压缩包进行下载
*
* @param file SpringMVC获取的图片文件
* @param response
* @throws Exception
*/
public static void pdfToImage(MultipartFile file, HttpServletResponse response) throws Exception {
File zipFile = generateImageFile(file);
downloadZipFile(zipFile, response);
}
/**
* 将PDF文件转换为多张图片并放入一个压缩包中
*
* @param file SpringMVC获取的图片文件
* @return 图片文件压缩包
* @throws Exception 抛出异常
*/
private static File generateImageFile(MultipartFile file) throws Exception {
String fileName = file.getOriginalFilename();
Document document = new Document();
document.setByteArray(file.getBytes(), 0, file.getBytes().length, fileName);
List<File> fileList = new ArrayList<>();
for (int i = 0; i < document.getNumberOfPages(); i++) {
BufferedImage image = (BufferedImage) document.getPageImage(i, GraphicsRenderingHints.SCREEN,
Page.BOUNDARY_CROPBOX, 0F, 2.5F);
File imageFile = new File((i + 1) + PNG_SUFFIX);
ImageIO.write(image, FORMAT_NAME, imageFile);
image.flush();
fileList.add(imageFile);
}
document.dispose();
String directoryName = fileName.substring(0, fileName.lastIndexOf("."));
File zipFile = new File(directoryName + ZIP_SUFFIX);
ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(zipFile));
zipFile(fileList, zos);
zos.close();
return zipFile;
}
/**
* 下载zip文件
*
* @param zipFile zip压缩文件
* @param response HttpServletResponse
* @throws IOException IO异常
*/
private static void downloadZipFile(File zipFile, HttpServletResponse response) throws IOException {
FileInputStream fis = new FileInputStream(zipFile);
byte[] bytes = new byte[fis.available()];
fis.read(bytes);
fis.close();
response.reset();
response.setCharacterEncoding("UTF-8");
response.setHeader("Content-Type", "application/x-msdownload");
response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(zipFile.getName(), "UTF-8"));
OutputStream out = response.getOutputStream();
out.write(bytes);
out.flush();
out.close();
zipFile.delete();
}
/**
* 压缩文件
*
* @param inputFiles 具体需要压缩的文件集合
* @param zos ZipOutputStream对象
* @throws IOException IO异常
*/
private static void zipFile(List<File> inputFiles, ZipOutputStream zos) throws IOException {
byte[] buffer = new byte[1024];
for (File file : inputFiles) {
if (file.exists()) {
if (file.isFile()) {
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
zos.putNextEntry(new ZipEntry(file.getName()));
int size = 0;
while ((size = bis.read(buffer)) > 0) {
zos.write(buffer, 0, size);
}
zos.closeEntry();
bis.close();
file.delete();
} else {
File[] files = file.listFiles();
List<File> childrenFileList = Arrays.asList(files);
zipFile(childrenFileList, zos);
}
}
}
}
}
```
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