Java实现pdf转图片，实现手机端、微信小程序预览pdf功能

1、maven依赖

  <dependency>
    <groupId>org.apache.pdfbox</groupId>
       <artifactId>fontbox</artifactId>
       <version>2.0.9</version>
   </dependency>
   <!-- https://mvnrepository.com/artifact/org.apache.pdfbox/pdfbox -->
   <dependency>
       <groupId>org.apache.pdfbox</groupId>
       <artifactId>pdfbox</artifactId>
       <version>2.0.9</version>
   </dependency>

2、工具类

package com.office.demo;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;

public class PdfConvertImageUtils {
    
    
    /**
     * PDF文档流转Png
     *
     * @param pdfFileInputStream
     * @return BufferedImage
     */
    public static BufferedImage pdfStreamToPng(InputStream pdfFileInputStream) {
    
    
        PDDocument doc = null;
        PDFRenderer renderer = null;
        try
        {
    
    
            doc = PDDocument.load(pdfFileInputStream);
            renderer = new PDFRenderer(doc);
            int pageCount = doc.getNumberOfPages();
            BufferedImage image = null;
            for (int i = 0; i < pageCount; i++)
            {
    
    
                if (image != null)
                {
    
    
                    image = combineBufferedImages(image, renderer.renderImageWithDPI(i, 144));
                }
                if (i == 0)
                {
    
    
                    // Windows native DPI
                    image = renderer.renderImageWithDPI(i, 144);
                }
                // BufferedImage srcImage = resize(image, 240, 240);//产生缩略图
            }
            return combineBufferedImages(image);
        } catch (IOException e)
        {
    
    
            e.printStackTrace();
        } finally
        {
    
    
            try
            {
    
    
                if (doc != null)
                {
    
    
                    doc.close();
                }
            } catch (IOException e)
            {
    
    
                e.printStackTrace();
            }
        }
        return null;
    }

    /**
     * BufferedImage拼接处理，添加分割线
     *
     * @param images
     * @return BufferedImage
     */
    public static BufferedImage combineBufferedImages(BufferedImage... images) {
    
    
        int height = 0;
        int width = 0;
        for (BufferedImage image : images)
        {
    
    
            //height += Math.max(height, image.getHeight());
            height += image.getHeight();
            width = image.getWidth();
        }
        BufferedImage combo = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = combo.createGraphics();
        int x = 0;
        int y = 0;
        for (BufferedImage image : images)
        {
    
    
            //int y = (height - image.getHeight()) / 2;
            // 线条粗细
            g2.setStroke(new BasicStroke(2.0f));
            // 线条颜色
            g2.setColor(new Color(193, 193, 193));
            // 线条起点及终点位置
            g2.drawLine(x, y, width, y);
            g2.drawImage(image, x, y, null);
            //x += image.getWidth();
            y += image.getHeight();
        }
        return combo;
    }

    /**
     * 通过Base64创建HTML文件并输出html文件
     *
     * @param base64
     * @param htmlPath html保存路径
     */
    public static void createHtmlByBase64(String base64, String htmlPath) {
    
    
        StringBuilder stringHtml = new StringBuilder();
        PrintStream printStream = null;
        try
        {
    
    
            // 打开文件
            printStream = new PrintStream(new FileOutputStream(htmlPath));
        } catch (FileNotFoundException e)
        {
    
    
            e.printStackTrace();
        }
        // 输入HTML文件内容
        stringHtml.append("<html><head>");
        stringHtml.append("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\">");
        stringHtml.append("<title></title>");
        stringHtml.append("</head>");
        stringHtml.append("<body style=\"\r\n" + "    text-align: center;\r\n" + "    background-color: #C1C1C1;\r\n" + "\">");
        stringHtml.append("<img src=\"data:image/png;base64," + base64 + "\" />");
        stringHtml.append("<a name=\"head\" style=\"position:absolute;top:0px;\"></a>");
        //添加锚点用于返回首页
        stringHtml.append("<a style=\"position:fixed;bottom:10px;right:10px\" href=\"#head\">回到首页</a>");
        stringHtml.append("</body></html>");
        try
        {
    
    
            // 将HTML文件内容写入文件中
            String s = stringHtml.toString();
            System.out.println(s);
            printStream.println(stringHtml.toString());
        } catch (Exception e)
        {
    
    
            e.printStackTrace();
        } finally
        {
    
    
            if (printStream != null)
            {
    
    
                printStream.close();
            }
        }
    }

    /**
     * bufferedImage 转为 base64编码
     *
     * @param bufferedImage
     * @return
     */
    public static String bufferedImageToBase64(BufferedImage bufferedImage) {
    
    
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        String png_base64 = "";
        try
        {
    
    
            // 写入流中
            ImageIO.write(bufferedImage, "png", byteArrayOutputStream);
            // 转换成字节
            byte[] bytes = byteArrayOutputStream.toByteArray();
            BASE64Encoder encoder = new BASE64Encoder();
            // 转换成base64串 删除 \r\n
            png_base64 = encoder.encodeBuffer(bytes).trim().replaceAll("\n", "").replaceAll("\r", "");
        } catch (IOException e)
        {
    
    
            e.printStackTrace();
        }
        return png_base64;
    }

    public static void main(String[] args) {
    
    
        InputStream inputStream = UrlUtils.getInputStreamByUrl("https://xxxxx/0ba8f215-e13c-4dbc-a693-c300f5690bfc.pdf");
        String htmlPath = "F:\\123.html";
        BufferedImage bufferedImage = null;
        try
        {
    
    
            bufferedImage = pdfStreamToPng(inputStream);
            String base64_png = bufferedImageToBase64(bufferedImage);
            createHtmlByBase64(base64_png, htmlPath);
        } catch (Exception e)
        {
    
    
            e.printStackTrace();
        } finally
        {
    
    
            try
            {
    
    
                if (inputStream != null)
                {
    
    
                    inputStream.close();
                }
            } catch (IOException e)
            {
    
    
                e.printStackTrace();
            }
        }
    }

}

url中获取文件流工具

package com.office.demo;

import org.apache.commons.io.IOUtils;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @Auther: ZHANG PU
 * @Date: 2023/4/26 10:12
 * @Description:
 */
public class UrlUtils {
    
    

    /**
     * 功能描述: 从地址中获取流
     *
     * @author zhang pu
     * @date 10:13 2023/4/26
     */
    public static InputStream getInputStreamByUrl(String strUrl) {
    
    
        HttpURLConnection conn = null;
        try
        {
    
    
            URL url = new URL(strUrl);
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(20 * 1000);
            final ByteArrayOutputStream output = new ByteArrayOutputStream();
            IOUtils.copy(conn.getInputStream(), output);
            return new ByteArrayInputStream(output.toByteArray());
        } catch (Exception e)
        {
    
    
            e.printStackTrace();
        } finally
        {
    
    
            try
            {
    
    
                if (conn != null)
                {
    
    
                    conn.disconnect();
                }
            } catch (Exception e)
            {
    
    
            }
        }
        return null;
    }

}

Java实现pdf转图片，实现手机端、微信小程序预览pdf功能

1、maven依赖

2、工具类

url中获取文件流工具

猜你喜欢