[英]Get access to CDI bean from another CDI bean
I have to get access to a session scoped CDI bean from another request scoped CDI bean. 我必须从另一个请求范围内的CDI bean访问会话范围内的CDI bean。 I have got:
我有:
At the moment when I try to get access to the session scoped bean from request scoped bean (through the @Inject
annotation) as you see below - I get the NullPointerException
exception in this line (which is located in addData
method): 如下所示,当我尝试从请求范围的bean(通过
@Inject
批注)访问会话范围的bean时,我在此行(位于addData
方法中)得到了NullPointerException
异常:
String surname=loginController.getCurrentUser().getSurname();
Could you tell me how can I fix this issue? 您能告诉我如何解决此问题吗?
Of course, If I print for example: #{loginController.currentUser.surname}
from any xhtml pages, everything works but I need access from the bean, not from the xhtml page. 当然,如果我以任何xhtml页面为例进行打印:
#{loginController.currentUser.surname}
,一切正常,但是我需要从bean(而不是xhtml页面)进行访问。
This is a part of login page: 这是登录页面的一部分:
<h:form class="form">
<p:growl id="growl" showDetail="false" />
<h:inputText id="username" value="#{userLogin.username}" label="Username" required="true" requiredMessage="Username: This field is required." title="Enter your username." pt:placeholder="Username" />
<h:inputSecret id="password" value="#{userLogin.password}" label="Password" required="true" requiredMessage="Password: This field is required." title="Enter your password." pt:placeholder="Password" />
<p:commandButton value="Login" action="#{loginController.login}" update="growl" styleClass="buttonStyle"/>
</h:form>
This is a session scoped CDI bean: 这是一个会话范围的CDI bean:
@Named
@SessionScoped
public class LoginController implements Serializable {
private static final long serialVersionUID = -6322113716363932422L;
public String login(){
if(userService.login(userLogin)){
currentUser=userService.getCurrnetUser(userLogin.getUsername());
return "home?faces-redirect=true";
}
else{
facesContext.addMessage(null, new FacesMessage("Data entered are incorrect"));
return null;
}
}
public String logout(){
currentUser=null;
return "login?faces-redirect=true";
}
public boolean isLoggedIn() {
return currentUser!=null;
}
@Produces
@LoggedIn
public UserAccount getCurrentUser(){
return currentUser;
}
@Inject
private FacesContext facesContext;
@Inject
private UserServiceImpl userService;
@Named
@Produces
@RequestScoped
private UserAccount userLogin=new UserAccount();
private UserAccount currentUser;
}
This is a request scoped CDI bean: 这是一个请求范围内的CDI bean:
@Named
@RequestScoped
public class DataServiceImpl implements DataService {
@Override
public void addData(String[] data) {
//Proccess some data
String surname=loginController.getCurrentUser().getSurname();
//Proccess some data
}
@Inject
private LoginController loginController;
}
This is a stacktrace: 这是一个堆栈跟踪:
18:45:08,968 WARNING [javax.enterprise.resource.webcontainer.jsf.lifecycle] (default task-15) #{dataController.send()}: java.lang.NullPointerException: javax.faces.FacesException: #{dataController.send()}: java.lang.NullPointerException
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
... 34 more
Caused by: java.lang.NullPointerException
at com.system.service.DataServiceImpl.addData(DataServiceImpl.java:24)
at com.system.controller.DataController.send(DataController.java:97)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at javax.el.ELUtil.invokeMethod(ELUtil.java:308)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:415)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:256)
at com.sun.el.parser.AstValue.invoke(AstValue.java:285)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
... 35 more
18:45:08,971 SEVERE [javax.enterprise.resource.webcontainer.jsf.context] (default task-15) javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at com.system.service.DataServiceImpl.addData(DataServiceImpl.java:24)
at com.system.controller.DataController.send(DataController.java:97)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at javax.el.ELUtil.invokeMethod(ELUtil.java:308)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:415)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:256)
at com.sun.el.parser.AstValue.invoke(AstValue.java:285)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
... 35 more
This is another CDI bean in which is located a send
method (from which I call to the addData
method) which we can see in the stacktrace: 这是另一个CDI bean,在其中可以找到我们可以在stacktrace中看到的
send
方法(从中调用addData
方法):
@Named
@ViewScoped
public class DataController implements Serializable {
private static final long serialVersionUID = 1383572529241805730L;
//some methods
public void send(){
if(uploadFile==null){
FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(FacesMessage.SEVERITY_ERROR, "The file isn't uploaded", "You should upload a file"));
}
else{
//Sending the data to the database...
list=new ArrayList<String>();
//It should be a upload file but for now I add it manually.
try(Stream<String> stream=Files.lines(Paths.get("F:/VirtualBox/Share/capture20110815.binetflow"))) {
list=stream.collect(Collectors.toList());
int start=0;
Pattern pattern=Pattern.compile(",");
dataService=new DataServiceImpl();
for (String s : list) {
if(start!=0){
String[] data=pattern.split(s);
dataService.addData(data);
}
else start++;
}
} catch (IOException e) {
e.printStackTrace();
}
FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO, "The data has been added.", ""));
}
}
@Named
@Produces
@RequestScoped
private UserTable userTable=new UserTable();
@Inject
private DataService dataService;
@Inject
private FacesContext facesContext;
@Inject
private Logger log;
private UploadedFile uploadFile;
private List<String> list;
}
I found the solution. 我找到了解决方案。 Step by step what I did:
一步一步地我做了什么:
I deleted the LoginController
from the DataServiceImpl
bean and I injected the UserAccount
with @LoggedIn
annotation to the DataController
bean: 我从
DataServiceImpl
bean中删除了LoginController
,并将带有@LoggedIn
批注的UserAccount
注入了DataController
bean:
@Named @ViewScoped public class DataController implements Serializable { //other fields and methods @Inject @LoggedIn private UserAccount currentUser; }
You can also inject the LoginController
to the DataController
bean instead of the UserAccount
but it isn't recommended. 您也可以将
LoginController
而不是UserAccount
注入到DataController
Bean中,但是不建议这样做。 You would better if you inject the UserAccount
. 如果注入
UserAccount
会更好。
I created the addCurrnetUser()
method in the DataServiceImpl
class. 我在
DataServiceImpl
类中创建了addCurrnetUser()
方法。 The parameter of the method is the UserAccount
object: 该方法的参数是
UserAccount
对象:
@Named @RequestScoped public class DataServiceImpl implements DataService { @Override public void addCurrentUser(UserAccount currentUser){ this.currentUser=currentUser; } @Override public void addData(String[] data) { //Proccess some data String surname=loginController.getCurrentUser().getSurname(); //Proccess some data } private UserAccount currentUser; }
I called dataService.addCurrentUser(currentUser)
in send()
method (which is located in the DataController
bean) before calling dataService.addData()
. 在调用
dataService.addData()
之前,我在send()
方法(位于DataController
bean中)中调用了dataService.addData()
dataService.addCurrentUser(currentUser)
dataService.addData()
。
You can also have a question: why does the injected LoginController
returns null
in the DataServiceImpl
bean and in the DataController
bean not? 您还可能有一个问题:为什么注入的
LoginController
在DataServiceImpl
bean中而不在DataController
bean中返回null
? Look at this discussion. 看这个讨论。 You can find a few reason there.
您可以在那里找到一些原因。
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