java.lang.ClassCastException 在 hibernate 4 中使用投影时
java.lang.ClassCastException While Using Projection in hibernate 4
我正在使用 hibernate 仅从 Entity 获取特定字段。为此，我使用 Criteria API 并使用投影。当我尝试遍历 Criteria API.
的 list() 方法返回的列表时，我得到了 ClassCastExcepiton
请帮我找出下面代码的缺失。
@RequestMapping("/pResult")
public String retrieveLpnOnPagination(Model model) {
for (int i = 1; i <= 9; i += 3) {
List<MyLpn> lpns = lpnService.retrievePaginatedResult(i, 3,new String[]{"lpnId","status","whse"});
for (MyLpn lpn : lpns)
System.out.println(lpn.toString());
System.out.println();
}
return "home";
}
DaoImpl 方法
public List<MyLpn> retrievePResult(int i, int j, String[] projectionFields) {
Session currentSession = sessionFactory.getCurrentSession();
Criteria createCriteria = currentSession.createCriteria(MyLpn.class);
ProjectionList projectionList = Projections.projectionList();
for (String field : projectionFields)
projectionList.add(Projections.property(field));
createCriteria.setProjection(projectionList);
List<MyLpn> list = createCriteria.list();
for (MyLpn lpn : list)
System.out.println(lpn.toString());
return list;
}
异常
SEVERE: Servlet.service() for servlet [spring] in context with path [/MyW2014] threw exception [Request processing failed; nested exception is java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.w.model.MyLpn] with root cause
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.w.model.MyLpn
at com.wmos.dao.LpnDaoImpl.retrievePResult(LpnDaoImpl.java:88)
at com.w.service.LpnService.retrievePaginatedResult(LpnService.java:43)
at com.wmos.service.LpnService$$FastClassBySpringCGLIB$e814eab.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655)
at com.wmos.service.LpnService$$EnhancerBySpringCGLIB$$bec224d4.retrievePaginatedResult(<generated>)
at com.wmos.controller.LpnController.retrieveLpnOnPagination(LpnController.java:57)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:860)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1136)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
谢谢。
试试这个
createCriteria.setResultTransformer(Transformers.aliasToBean(MyLpn.class));
List<MyLpn> list = createCriteria.list();
我正在使用 hibernate 仅从 Entity 获取特定字段。为此，我使用 Criteria API 并使用投影。当我尝试遍历 Criteria API.
的 list() 方法返回的列表时，我得到了 ClassCastExcepiton请帮我找出下面代码的缺失。
@RequestMapping("/pResult")
public String retrieveLpnOnPagination(Model model) {
for (int i = 1; i <= 9; i += 3) {
List<MyLpn> lpns = lpnService.retrievePaginatedResult(i, 3,new String[]{"lpnId","status","whse"});
for (MyLpn lpn : lpns)
System.out.println(lpn.toString());
System.out.println();
}
return "home";
}
DaoImpl 方法
public List<MyLpn> retrievePResult(int i, int j, String[] projectionFields) {
Session currentSession = sessionFactory.getCurrentSession();
Criteria createCriteria = currentSession.createCriteria(MyLpn.class);
ProjectionList projectionList = Projections.projectionList();
for (String field : projectionFields)
projectionList.add(Projections.property(field));
createCriteria.setProjection(projectionList);
List<MyLpn> list = createCriteria.list();
for (MyLpn lpn : list)
System.out.println(lpn.toString());
return list;
}
异常
SEVERE: Servlet.service() for servlet [spring] in context with path [/MyW2014] threw exception [Request processing failed; nested exception is java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.w.model.MyLpn] with root cause
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.w.model.MyLpn
at com.wmos.dao.LpnDaoImpl.retrievePResult(LpnDaoImpl.java:88)
at com.w.service.LpnService.retrievePaginatedResult(LpnService.java:43)
at com.wmos.service.LpnService$$FastClassBySpringCGLIB$e814eab.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655)
at com.wmos.service.LpnService$$EnhancerBySpringCGLIB$$bec224d4.retrievePaginatedResult(<generated>)
at com.wmos.controller.LpnController.retrieveLpnOnPagination(LpnController.java:57)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:860)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1136)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
谢谢。
试试这个
createCriteria.setResultTransformer(Transformers.aliasToBean(MyLpn.class));
List<MyLpn> list = createCriteria.list();