Hibernate：引起：java.lang.ClassCastException：[Ljava.lang.Object;不能轉換爲<package.class>

我有問題從數據庫中獲取數據並將其轉換爲我需要的類型。Hibernate：引起：java.lang.ClassCastException：[Ljava.lang.Object;不能轉換爲<package.class>

我嘗試使用Spring安全性從數據庫中泄漏用戶。它的工作方式如下：我插入用戶名和密碼和方法loadUserByUserName(String userName)從UserDetailsServiceImpl類到數據庫和cheaks是用戶存在於數據庫中，如果是（用戶存在於數據庫中），然後從數據庫中獲取並授權用戶並呈現給他安全頁面。但問題是在我的DAO中，impl類的方法不能將它轉換爲需要我的對象 - App1User我的實體類和我在登錄頁面上看到的消息是這樣的（原因：[Ljava.lang.Object;不能轉換爲app1.domain .App1User enter code here）：

我在DAOImpl類方法：

public App1User findUserByName(String userName) { 


     Session session = sessionFactory.openSession(); 
     Transaction transaction = session.beginTransaction(); 
     List<App1User> listUser = null; 


     try { 

      String stringSQL = "select au.userId, au.firstName, au.lastName, au.middleName, au.username, au.password, au.userPosition from App1User au where au.username = :userNameArg"; 
      Query query = session.createQuery(stringSQL); 
      query.setParameter("userNameArg", userName); 

      listUser = (List<App1User>)query.list(); 

      session.flush();  
      session.clear(); 
      transaction.commit(); 

     } catch(HibernateException e) { 

      System.err.println(e); 

      if(transaction != null) 
       transaction.rollback(); 

     } finally { 
      if(session != null) 
       session.close(); 
     } 

     return (App1User)listUser.get(0); 
    }

我hibernate.hbm.xml

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 

<hibernate-configuration> 

    <session-factory> 

     <property name="hibernate.current_session_context_class">thread</property> 

     <property name="hibernate.default_schema">PUBLIC</property> 

     <!-- JDBC connection pool (use the built-in) --> 
     <property name="connection.pool_size">1</property> 

     <property name="hibernate.transaction.auto_close_session">false</property> 

     <!-- SQL dialect --> 
     <property name="dialect">org.hibernate.dialect.H2Dialect</property> 

     <!-- Disable the second-level cache --> 
     <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property> 

     <!-- Echo all executed SQL to stdout --> 
     <property name="show_sql">true</property> 

     <!-- Drop and re-create the database schema on startup --> 
     <property name="hbm2ddl.auto">create</property> 

     <mapping resource="/WEB-INF/hibernateConf/App1User.hbm.xml"/> 

    </session-factory> 

</hibernate-configuration>

的例外，我現在所擁有的：

SEVERE: An internal error occurred while trying to authenticate the user. 
org.springframework.security.authentication.InternalAuthenticationServiceException: [Ljava.lang.Object; cannot be cast to app1.domain.App1User 
    at org.springframework.security.authentication.dao.DaoAuthenticationProvider.retrieveUser(DaoAuthenticationProvider.java:125) 
    at org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.authenticate(AbstractUserDetailsAuthenticationProvider.java:143) 
    at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:167) 
    at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:192) 
    at org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter.attemptAuthentication(UsernamePasswordAuthenticationFilter.java:93) 
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:217) 
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) 
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120) 
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) 
    at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:120) 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) 
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64) 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) 
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:53) 
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) 
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91) 
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) 
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213) 
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176) 
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344) 
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219) 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) 
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142) 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) 
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610) 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518) 
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091) 
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668) 
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223) 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517) 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
    at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to app1.domain.App1User 
    at app1.persistance.UserManageDAOImpl.findUserByName(UserManageDAOImpl.java:102) 
    at app1.web.authentification.UserDetailsServiceImpl.loadUserByUsername(UserDetailsServiceImpl.java:36) 
    at org.springframework.security.authentication.dao.DaoAuthenticationProvider.retrieveUser(DaoAuthenticationProvider.java:114) 
    ... 42 more

，也是我UserDetailServiceImpl類：

public UserDetails loadUserByUsername(String userName) 
               throws UsernameNotFoundException { 


     App1User listUser = userManageDAOIF.findUserByName(userName); 
     String password = null; 
     Collection<GrantedAuthority> authorities = null; 

     if(listUser != null) { 

       password = (String)listUser.getPassword(); 

       authorities = new ArrayList<GrantedAuthority>(); 

        authorities.add(new SimpleGrantedAuthority("ROLE_USER")); 


       org.springframework.security.core.userdetails.User secureUser = new 
         org.springframework.security.core.userdetails.User(userName, password, authorities); 

       return secureUser; 

     } else { 

      throw new UsernameNotFoundException("No user exist in datbase"); 
     } 

    }

來源

2015-04-15 java_user

當您選擇從DB特定的列，你得到的結果是沒有實體的對象，而是一個Object[]，與持有不同的列值的數組中的每個元素。那麼，你從query.list()得到的方法是：List<Object[]>。所以當然，當你投list.get(0)，到App1User，這將導致ClassCastException。

所以，要麼你得到的Object[]和建立這樣的App1User實體對象：

// size of this array would be number of columns in select query 
Object[] attr = listUser.get(0); 
App1User appUser = new App1User(attr[0], attr[1], attr[2], ...);

當然不是最好的方式。更好的方法是從數據庫獲取List<App1User>。

String stringSQL = "select au.userId, au.firstName, au.lastName, au.middleName, au.username, au.password, au.userPosition from App1User au where au.username = :userNameArg";

到：對於剛剛從更改查詢

String stringSQL = "select au from App1User au where au.username = :userNameArg";

來源

2015-04-15 16:56:18

這是halped。請告訴我這與HQL有關，hibernate如何從數據庫中選擇數據，我需要閱讀的內容，對吧？ –

@java_user是的。你可以閱讀關於這個的Hibernate文檔。 –

這幫了我。我改變了SQL查詢，它工作完美。感謝@RohitJain – Ruthwik

Hibernate：引起：java.lang.ClassCastException：[Ljava.lang.Object;不能轉換爲<package.class>

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