【代码片】Pdf转Image

pdf转图片工具类

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;

public class Pdf2Png {

    private final static String type = "png";
    public static byte[] pdfToImage(byte[] pdfBytes) {
        PDDocument pdDocument = null;
        ByteArrayOutputStream bao = null;
        byte[] imageBytes = null;
        try {
            int dpi = 296;
            pdDocument = PDDocument.load(pdfBytes);
            PDFRenderer renderer = new PDFRenderer(pdDocument);
            ///int pageCount = pdDocument.getNumberOfPages();
            /* dpi越大转换后越清晰，相对转换速度越慢 */
            /// for (int i = 0; i < pageCount; i++)
            // 转化第一张
            BufferedImage image = renderer.renderImageWithDPI(0, dpi);
            bao = new ByteArrayOutputStream();
            ImageIO.write(image, type, bao);
            imageBytes = bao.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 这里需要关闭PDDocument，不然如果想要删除pdf文件时会提示文件正在使用，无法删除的情况
                if (null != bao) {
                    bao.close();
                }
                if (null != pdDocument) {
                    pdDocument.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return imageBytes;
    }
}

byte[]转字符串数据

适用场景：接口交互传输文件

import org.apache.commons.codec.binary.Base64;
import java.nio.file.Files;
import java.nio.file.Paths;
public class T {
    public static void main(String[] args) throws IOException {
        String fileName = "D:\\pdf.pdf";
        byte[] bytes = Files.readAllBytes(Paths.get(fileName));
        String pdfContent = Base64.encodeBase64String(bytes);
        byte[] byte2 = Base64.decodeBase64(pdfContent);
        String pdfContent2 = Base64.encodeBase64String(byte2);
        System.out.println(pdfContent.equals(pdfContent2));
    }
}