我正在开发一个java ee Web应用程序。一切都工作正常，直到我在我的EJB中使用JPA。我一直在寻找，但我没有在哪里。 这是我的EJB
Stateless(name = "SignupEJB")
public class SignupBean {
@PersistenceContext (unitName = "mypersistenceUnit")
EntityManager em;
UsersEntity user=new UsersEntity();
CountriesEntity countriesName=new CountriesEntity();
public SignupBean() {
}
public List<String> getCountries(){
List<String> countries=new ArrayList<String>();
String[] tmp=new String[9];
int i=0;
for(;i<tmp.length;i++){
tmp[i]=countriesName.getName();
}
countries= Arrays.asList(tmp);
return countries;
}
public void setValues(String fname,String lname, String email, String pass,
String country, String phno, String altmail) {
user.setId(user.getId()+1);
user.setfName(fname);
user.setlName(lname);
user.setEmail(email);
user.setPassme(pass);
user.setCountry(country);
user.setPhNo(phno);
user.setAltMail(altmail);
em.persist(user);
}
}
这里是persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" version="2.1">
<persistence-unit name="mypersistenceUnit">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>com.persistence.UsersEntity</class>
<class>com.persistence.CountriesEntity</class>
<properties>
<property name="eclipselink.jdbc.url" value="jdbc:mysql://localhost:3306/Project22"/>
<property name="eclipselink.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="eclipselink.jdbc.user"/>
<property name="eclipselink.jdbc.password"/>
</properties>
</persistence-unit>
</persistence>
我正在使用
这是服务器日志
java.lang.NullPointerException
at java.util.Hashtable.put(Hashtable.java:459)
at com.sun.enterprise.deployment.PersistenceUnitDescriptor.addProperty(PersistenceUnitDescriptor.java:187)
at com.sun.enterprise.deployment.node.PersistenceUnitNode.startElement(PersistenceUnitNode.java:90)
at com.sun.enterprise.deployment.node.SaxParserHandler.startElement(SaxParserHandler.java:502)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:509)
at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:182)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:357)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2787)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:118)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:327)
at com.sun.enterprise.deployment.io.DeploymentDescriptorFile.read(DeploymentDescriptorFile.java:318)
at com.sun.enterprise.deployment.archivist.ExtensionsArchivist.open(ExtensionsArchivist.java:179)
at com.sun.enterprise.deployment.archivist.PersistenceArchivist.readPersistenceDeploymentDescriptor(PersistenceArchivist.java:143)
at com.sun.enterprise.deployment.archivist.WarPersistenceArchivist.open(WarPersistenceArchivist.java:93)
at com.sun.enterprise.deployment.archivist.Archivist.readRestDeploymentDescriptors(Archivist.java:405)
at com.sun.enterprise.deployment.archivist.Archivist.readDeploymentDescriptors(Archivist.java:396)
at com.sun.enterprise.deployment.archivist.Archivist.open(Archivist.java:271)
at com.sun.enterprise.deployment.archivist.Archivist.open(Archivist.java:280)
at com.sun.enterprise.deployment.archivist.Archivist.open(Archivist.java:241)
at com.sun.enterprise.deployment.archivist.ApplicationFactory.openArchive(ApplicationFactory.java:161)
at org.glassfish.javaee.core.deployment.DolProvider.processDOL(DolProvider.java:203)
at org.glassfish.javaee.core.deployment.DolProvider.load(DolProvider.java:227)
at org.glassfish.javaee.core.deployment.DolProvider.load(DolProvider.java:96)
at com.sun.enterprise.v3.server.ApplicationLifecycle.loadDeployer(ApplicationLifecycle.java:881)
at com.sun.enterprise.v3.server.ApplicationLifecycle.setupContainerInfos(ApplicationLifecycle.java:821)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:377)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:219)
at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:491)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$2$1.run(CommandRunnerImpl.java:539)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$2$1.run(CommandRunnerImpl.java:535)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:360)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$2.execute(CommandRunnerImpl.java:534)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$3.run(CommandRunnerImpl.java:565)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$3.run(CommandRunnerImpl.java:557)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:360)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:556)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1464)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1300(CommandRunnerImpl.java:109)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1846)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1722)
at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:534)
at com.sun.enterprise.v3.admin.AdminAdapter.onMissingResource(AdminAdapter.java:224)
at org.glassfish.grizzly.http.server.StaticHttpHandlerBase.service(StaticHttpHandlerBase.java:189)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
]]
答案 0 :(得分：1)
我认为你不能以这种方式使用EJB bean。 Container将为您创建任意数量的SignupBean bean。每次调用SignupBean时，您都可以获得它的另一个实例。 删除此代码：
UsersEntity user=new UsersEntity();
CountriesEntity countriesName=new CountriesEntity();
另外，不要生成这样的id：
user.setId(user.getId()+1);
将其设置为自动增量。设置ID的自动生成：http://www.objectdb.com/java/jpa/entity/generated