我正在使用注射，但我遇到了一些问题：
HTTP Status 500 - javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is:
type Exception report
message javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is:
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is:
java.lang.NullPointerException
javax.faces.webapp.FacesServlet.service(FacesServlet.java:321)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
javax.faces.el.EvaluationException: javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is:
java.lang.NullPointerException
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
javax.faces.component.UICommand.broadcast(UICommand.java:311)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is:
java.lang.NullPointerException
org.apache.openejb.core.ivm.BaseEjbProxyHandler.convertException(BaseEjbProxyHandler.java:408)
org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:312)
pl.konrad.daoTest.ServiceUzytkownik$$LocalBeanProxy.dodaj(pl/konrad/daoTest/ServiceUzytkownik.java)
pl.konrad.beans.UzytkownikBean.dodajUzytkownika(UzytkownikBean.java:84)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.el.parser.AstValue.invoke(AstValue.java:278)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:273)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
javax.faces.component.UICommand.broadcast(UICommand.java:311)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
java.lang.NullPointerException
pl.konrad.daoTest.ServiceUzytkownik.dodaj(ServiceUzytkownik.java:17)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:192)
org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:173)
org.apache.openejb.monitoring.StatsInterceptor.record(StatsInterceptor.java:181)
org.apache.openejb.monitoring.StatsInterceptor.invoke(StatsInterceptor.java:100)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:192)
org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:173)
org.apache.openejb.core.interceptor.InterceptorStack.invoke(InterceptorStack.java:85)
org.apache.openejb.core.stateless.StatelessContainer._invoke(StatelessContainer.java:227)
org.apache.openejb.core.stateless.StatelessContainer.invoke(StatelessContainer.java:194)
org.apache.openejb.core.ivm.EjbObjectProxyHandler.synchronizedBusinessMethod(EjbObjectProxyHandler.java:308)
org.apache.openejb.core.ivm.EjbObjectProxyHandler.businessMethod(EjbObjectProxyHandler.java:303)
org.apache.openejb.core.ivm.EjbObjectProxyHandler._invoke(EjbObjectProxyHandler.java:92)
org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:308)
pl.konrad.daoTest.ServiceUzytkownik$$LocalBeanProxy.dodaj(pl/konrad/daoTest/ServiceUzytkownik.java)
pl.konrad.beans.UzytkownikBean.dodajUzytkownika(UzytkownikBean.java:84)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.el.parser.AstValue.invoke(AstValue.java:278)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:273)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
javax.faces.component.UICommand.broadcast(UICommand.java:311)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
note The full stack trace of the root cause is available in the Apache Tomcat (TomEE)/7.0.55 (1.7.1) logs.
这是我的Bean：
@ManagedBean(name = "uzytkownikBean")
@ViewScoped
public class UzytkownikBean implements Serializable {
private static final long serialVersionUID = 1L;
private Uzytkownik uzytkownik;
private DataModel<Uzytkownik> modelUzytkownicy;
@EJB
private ServiceUzytkownik serviceUzytkownik;
public Uzytkownik getUzytkownik() {
return uzytkownik;
}
public void setUzytkownik(Uzytkownik uzytkownik) {
this.uzytkownik = uzytkownik;
}
public DataModel<Uzytkownik> getModelUzytkownicy() {
return modelUzytkownicy;
}
public void setModelUzytkownicy(ArrayDataModel<Uzytkownik> modelUzytkownicy) {
this.modelUzytkownicy = modelUzytkownicy;
}
@PostConstruct
public void init() {
uzytkownik = new Uzytkownik();
}
public void dodajUzytkownika() {
serviceUzytkownik.dodaj(uzytkownik);
}
}
我的EJB类：
@Stateless
public class ServiceUzytkownik {
@PersistenceContext
private EntityManager em;
public void dodaj(Uzytkownik uzytkownik) {
em.persist(uzytkownik);
}
}
现在怎么了？如果我应该将它添加到persistence.xml。这是我对Hibernate的配置。在创建动态Web项目时，会添加连接，因此可能没有必要。但就目前而言，我必须摆脱这个错误。连接到数据库时出错可能看起来不一样。
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.user" value="konrad" />
<property name="javax.persistence.jdbc.password" value="konrad" />
<property name="javax.persistence.jdbc.url"
value="jdbc:mysql://localhost:3306/bazahealthhelper" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect" />
<property name="hibernate.hbm2ddl.auto" value="create" />
</properties>