Question

一旦我尝试执行em.persist（object）或em.merge（object），它就会崩溃。 Em.remove（）和格式化的查询都可以正常工作。

在localhost上工作。我正在使用HSQLDB 1.8使用JPA ORM存储来自JAVA EE项目的数据。由于我能够查询实体，因此指向数据库的链接工作正常。

   @Stateful
   public class LibraryBean implements library.libraryservice.LibraryService {

      @PersistenceContext(name = "LibraryPU", type=PersistenceContextType.EXTENDED)
      private EntityManager em;


      public void addBook(Book b) {
         em.persist(b);
      }


      public List<String> getAllBookStrings() {
         return (List<String>) em.createQuery("FROM Book    b").getResultList();
      }
    }

   public void populateLibraryDB() {

      books = libraryService.getAllBooks(); 
      for(Book book : books)
         libraryService.deleteBook(book);

      // Creating the books
      books.add(new Book("Testbook", "Description bla", "Heinrich Heine", 0, Language.German));

      for(Book book : books)
         libraryService.addBook(book);
   }

完整代码：https://github.com/PierreAnken/Book_EE

它应该只用DB写，但是崩溃了。

Context Path:/Library-0.0.1
Servlet Path:/faces
Path Info:/index.xhtml
Query String:null
Stack Trace
javax.servlet.ServletException: javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not prepare statement
javax.faces.webapp.FacesServlet.service(FacesServlet.java:671)
io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:805)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
java.lang.Thread.run(Thread.java:748)

我会做

Object object = em.merge(object);
em.persist(object);

无法持久化实体

0 个答案: