我不能在Netbeans7.0中使用实体类(JPA)

Question

我尝试在Netbeans7.0中使用实体类( Entity，JPA)，但它不起作用。

创建企业应用程序名称BookApp.

创建实体类

在BookApp上右键单击，然后选择实体类、fron、

1. 对话框、新建实体类，从数据库中插入JNDI名称:jdbc/ test ，用于连接到测试数据库，并选择表图书。之后，单击Next以插入包: entity，然后单击Finish.

。

创建会话Bean

1. I在BookApp-ejb上右键单击会话Beans为实体类并单击Next。
2. i单击Add All >>并单击Next。
3. i插入包:sbE 227、E 128create Interface:LocalE 229并单击Finish。H 230G 231

创建Web应用程序

1. I右键单击BookApp-war并选择:findBook并单击Finish。

1. I右键单击BookApp-war并选择Servlet插入文件名: ShowBook，包:Servlet并单击Finish.

H 151我在编辑器中右击并选择E 152插入代码…>调用企业Bean…

1. In对话框调用Enterprise我选择BooksFacade并单击OK.
2. 取消注释html并在out.println("");

之间插入此代码

字符串isbn = request.getParameter("isbn")；图书= booksFacade.find(isbn)；out.println(标题：“+ book.getTitle()+”)；out.println(“作者：+ book.getAuthor() +”)；out.println(“价格：”+ book.getPrice() + "")；

1. I清理和构建BookApp.
2. I运行BookApp.
3. 我转到这个URL http://localhost:8080/BookApp-war/findBook.html并从图书表中插入isbn，但是当我单击Find按钮时，它显示的错误如下.

HTTP 500 -类型的异常报告消息descriptionThe服务器遇到一个内部错误()

使它无法满足这一要求。

异常javax.ejb.EJBException

我不知道我错了什么。我删除会话bean并再次创建会话bean，但没有创建接口。当我运行BookApp时，它会显示相同的错误。我是EJB的新手。请帮帮我。

我不知道哪里有错误，但是在我构建时，这段代码出现在服务器日志中。

INFO: file:/C:/Users/Mc/Documents/NetBeansProjects/BookApp/dist/gfdeploy/BookApp/BookApp-ejb_jar/_BookApp-ejbPU logout successful
SEVERE: java.io.IOException: Error creating temporary file transfer folder
    at org.glassfish.admin.payload.PayloadFilesManager.createTempFolder(PayloadFilesManager.java:718)
    at org.glassfish.admin.payload.PayloadFilesManager.createTempFolder(PayloadFilesManager.java:727)
    at org.glassfish.admin.payload.PayloadFilesManager.access$100(PayloadFilesManager.java:95)
    at org.glassfish.admin.payload.PayloadFilesManager$Temp.<init>(PayloadFilesManager.java:303)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$UploadedFilesManager.extractFiles(CommandRunnerImpl.java:1413)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$UploadedFilesManager.<init>(CommandRunnerImpl.java:1394)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$UploadedFilesManager.<init>(CommandRunnerImpl.java:1372)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:821)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1200(CommandRunnerImpl.java:96)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1247)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1235)
    at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:465)
    at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:222)
    at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:168)
    at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:117)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:234)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:822)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:719)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1013)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.io.IOException: Unknown error creating directory C:\Users\Mc\.netbeans\7.0\config\GF3\domain1\applications\xfer-5751472689020834694
    at org.glassfish.admin.payload.PayloadFilesManager.createTempFolder(PayloadFilesManager.java:709)
    ... 29 more

在我单击HTML按钮调用ShowBook servlet后，这段代码将出现在服务器日志中。

INFO: entity.Books actually got transformed
INFO: Portable JNDI names for EJB BooksFacade : [java:global/BookApp/BookApp-ejb/BooksFacade, java:global/BookApp/BookApp-ejb/BooksFacade!sb.BooksFacadeLocal]
INFO: WEB0671: Loading application [BookApp#BookApp-war.war] at [BookApp-war]
INFO: BookApp was successfully deployed in 7,063 milliseconds.
INFO: Instantiated an instance of org.hibernate.validator.engine.resolver.JPATraversableResolver.
INFO: EclipseLink, version: Eclipse Persistence Services - 2.2.0.v20110202-r8913
INFO: file:/C:/Users/Mc/Documents/NetBeansProjects/BookApp/dist/gfdeploy/BookApp/BookApp-ejb_jar/_BookApp-ejbPU login successful
WARNING: A system exception occurred during an invocation on EJB BooksFacade method public entity.Books sb.BooksFacade.find(java.lang.Object)
javax.ejb.EJBException
    at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5194)
    at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5092)
    at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4880)
    at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2039)
    at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1990)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:88)
    at $Proxy203.find(Unknown Source)
    at servlets.ShowBook.processRequest(ShowBook.java:46)
    at servlets.ShowBook.doPost(ShowBook.java:79)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:755)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1534)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:326)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:227)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:170)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:822)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:719)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1013)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.IllegalArgumentException: You have provided an instance of an incorrect PK class for this find operation.  Class expected : class java.lang.Integer, Class received : class java.lang.String.
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.findInternal(EntityManagerImpl.java:695)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.find(EntityManagerImpl.java:619)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.find(EntityManagerImpl.java:498)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.find(EntityManagerWrapper.java:320)
    at sb.AbstractFacade.find(AbstractFacade.java:36)
    at sb.BooksFacade.find(BooksFacade.java:16)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)
    at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)
    at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5367)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:801)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:862)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:801)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:371)
    at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5339)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5327)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)
    ... 31 more

WARNING: StandardWrapperValve[ShowBook]: PWC1406: Servlet.service() for servlet ShowBook threw exception
javax.ejb.EJBException
    at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5194)
    at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5092)
    at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4880)
    at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2039)
    at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1990)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:88)
    at $Proxy203.find(Unknown Source)
    at servlets.ShowBook.processRequest(ShowBook.java:46)
    at servlets.ShowBook.doPost(ShowBook.java:79)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:755)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1534)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:326)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:227)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:170)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:822)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:719)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1013)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.IllegalArgumentException: You have provided an instance of an incorrect PK class for this find operation.  Class expected : class java.lang.Integer, Class received : class java.lang.String.
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.findInternal(EntityManagerImpl.java:695)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.find(EntityManagerImpl.java:619)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.find(EntityManagerImpl.java:498)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.find(EntityManagerWrapper.java:320)
    at sb.AbstractFacade.find(AbstractFacade.java:36)
    at sb.BooksFacade.find(BooksFacade.java:16)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)
    at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)
    at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5367)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:801)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:862)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:801)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:371)
    at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5339)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5327)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)
    ... 31 more

Answer 1

实体管理器不喜欢字符串参数。

Caused by: java.lang.IllegalArgumentException: You have provided an
instance of an incorrect PK class for this find operation.  Class
expected : class java.lang.Integer, Class received : class
java.lang.String.

实体管理器的find方法搜索具有给定id的实体，或从带有给定PK的db视图中搜索实体。我想你有一个这样的书实体：

@Entity    
public class Book {

   @Id
   private Integer isbn;


....

因此，您必须将一个Integer传递给find方法。

em.find(Integer.parseInt(isbn)) //just a hack

我希望这对你有帮助。