我正在使用帶有 spring data jpa 的 spring boot 應用程序。當我遍歷對象時出現并發修改異常。當我遍歷 submission.getPages() 時，我得到了 concurrentModificationException。我厭倦了檢查 null 和 empty 但沒有運氣@Override public void processCopyAttachmentsToProcessAttachments(int processId) { Optional<Process> processOpt = processRepository.findById(processId); if (processOpt.isEmpty()) { return; } Process process = processOpt.get(); Hibernate.initialize(process.getSubmissons()); List<Submission> submissions = process.getSubmissons(); if (submissions == null || submissions.isEmpty()) return; for (Submission submission : submissions) { Hibernate.initialize(submission.getPages()); if (submission.getPages() == null || submission.getPages().isEmpty()) return; for (SubmissionPage submissionPage : submission.getPages()) { Hibernate.initialize(submissionPage.getAttachments()); if (submissionPage.getAttachments() == null || submissionPage.getAttachments().isEmpty()) return; for (SubmissionPageAttachment submissionPageAttachment : submissionPage.getAttachments()) { ProcessAttachment processAttachment = new ProcessAttachment(); processAttachment.setDocumentId(submissionPageAttachment.getDocumentId()); processAttachment.setDocumentType(submissionPageAttachment.getDocumentType()); processAttachment.setProcess(process); processAttachmentRepository.save(processAttachment); } } } }如何解決這個問題？
1 回答
紅顏莎娜
TA貢獻1842條經驗 獲得超13個贊
再次檢查您的問題，我認為罪魁禍首是Hibernate.initialize. 因為它修改了傳遞的對象。
這是該方法的源代碼。正如我們清楚地看到的，它修改了它們的狀態，并且因為我們知道ConcurrentModificationException在迭代時內容被更改時會發生這種情況，這顯然是原因。
public static void initialize(Object proxy) throws HibernateException {
if ( proxy == null ) {
return;
}
if ( proxy instanceof HibernateProxy ) {
( (HibernateProxy) proxy ).getHibernateLazyInitializer().initialize();
}
else if ( proxy instanceof PersistentCollection ) {
( (PersistentCollection) proxy ).forceInitialization();
}
else if ( proxy instanceof PersistentAttributeInterceptable ) {
final PersistentAttributeInterceptable interceptable = (PersistentAttributeInterceptable) proxy;
final PersistentAttributeInterceptor interceptor = interceptable.$$_hibernate_getInterceptor();
if ( interceptor instanceof EnhancementAsProxyLazinessInterceptor ) {
( (EnhancementAsProxyLazinessInterceptor) interceptor ).forceInitialize( proxy, null );
}
}
}
當使用常規的 for 循環時，它一次從集合中訪問一個對象，因此它不會出現異常。
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