Re: pdfbox在springboot的多线程中出现java.util.ConcurrentModificationException

[Tilman Hausherr]

I suspect the problem is because you're accessing the initial document 
from multiple threads.

Tilman
Am 23.03.2022 um 09:52 schrieb 1540731...@qq.com.INVALID:
@RequestMapping(value = "/test", method = RequestMethod.GET)
public void test(HttpServletResponse response,
                  HttpServletRequest request) throws IOException, 
InterruptedException {
     logger.info("==========test============");
     String path = "H:\\dd\\pdf\\a\\韩顺平_循序渐进学Java零基础【完整笔记】.pdf";
     String toPath1 = "H:\\dd\\pdf\\a\\韩顺平_循序渐进学Java零基础【完整笔记】test1.pdf";
     String toPath2 = "H:\\dd\\pdf\\a\\韩顺平_循序渐进学Java零基础【完整笔记】test2.pdf";
     String toPath3 = "H:\\dd\\pdf\\a\\韩顺平_循序渐进学Java零基础【完整笔记】test3.pdf";
     PDDocument document = PDDocument.load(new File(path));
     PDPageTree pages = document.getPages();
     Iterator<PDPage&gt; iterator = pages.iterator();
     int numberOfPages = document.getNumberOfPages();
     System.out.println("numberOfPages = " + numberOfPages);
     CountDownLatch count = new CountDownLatch(3);
     new Thread(()-&gt;{
         PDDocument to = new PDDocument();
         for (int i = 0; i < 1000; i++) {
             to.addPage(document.getPage(i));
         }
         try {
             System.out.println(to);

             to.save(toPath1);
             to.close();
         } catch (IOException e) {
             e.printStackTrace();
         }
         count.countDown();
     }).start();
     new Thread(()-&gt;{
         PDDocument to = new PDDocument();
         for (int i = 0; i < 500; i++) {
             to.addPage(document.getPage(i));
         }
         try {
             System.out.println(to);
             to.save(toPath2);
             to.close();
         } catch (IOException e) {
             e.printStackTrace();
         }
         count.countDown();

     }).start();
     new Thread(()-&gt;{
         PDDocument to = new PDDocument();
         for (int i = 0; i < 100; i++) {
             to.addPage(document.getPage(i));
         }
         try {
             System.out.println(to);

             to.save(toPath3);
             to.close();
         } catch (IOException e) {
             e.printStackTrace();
         }
         count.countDown();

     }).start();
     count.await();
     document.close();
}



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