问题描述
我试图再次建立Java JSF网站,并且当我单击“加载”按钮时发生此错误。
(即使用glassfish服务器和netbeans)
据我所知,我必须在bean中具有getter和setter方法,我还认为Managedbean和范围内的应用程序应该是正确的注释,这就是我使用的方法:
JDK 11 JSF 2.2 Java EE Web 7 API库
javax.faces.el.EvaluationException: javax.el.PropertyNotFoundException: /index.xhtml @15,78 action="#{mainBean.fillArrays()}": Target Unreachable,identifier 'mainBean' resolved to null
at com.sun.faces.application.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:70)
at com.sun.faces.application.ActionListenerImpl.getNavigationOutcome(ActionListenerImpl.java:82)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:71)
at javax.faces.component.UICommand.broadcast(UICommand.java:222)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:847)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1395)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:58)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:76)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:177)
at javax.faces.webapp.FacesServlet.executeLifecyle(FacesServlet.java:707)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:451)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1540)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:119)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:611)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:550)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:75)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:114)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:332)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:199)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:439)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:144)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:182)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:156)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:218)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:95)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:260)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:177)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:109)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:88)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:53)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:515)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:89)
at org.glassfish.grizzly.strategies.WorkerThreadioStrategy.run0(WorkerThreadioStrategy.java:94)
at org.glassfish.grizzly.strategies.WorkerThreadioStrategy.access$100(WorkerThreadioStrategy.java:33)
at org.glassfish.grizzly.strategies.WorkerThreadioStrategy$WorkerThreadRunnable.run(WorkerThreadioStrategy.java:114)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:569)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:549)
at java.lang.Thread.run(Thread.java:748)
Caused by: javax.el.PropertyNotFoundException: /index.xhtml @15,identifier 'mainBean' resolved to null
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:67)
at com.sun.faces.application.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:66)
... 38 more
我的index.xhtml
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:f="http://xmlns.jcp.org/jsf/core">
<h:head>
<title>Widow HS</title>
</h:head>
<h:body>
<h:form>
<h:commandButton action="#{mainBean.fillArrays()}" value="load"/>
<h:dataTable value="#{mainBean.userarray}" var="u">
<h:column>
<f:facet name="header">username</f:facet>
<h:outputText value="#{u.username}"/>
</h:column>
<h:column>
<f:facet name="header">Kills</f:facet>
<h:outputText value="#{mainBean.getAllKills(u)}"/>
</h:column>
<h:column>
<f:facet name="header">Deaths</f:facet>
<h:outputText value="#{mainBean.getAllDeaths(u)}"/>
</h:column>
</h:dataTable>
</h:form>
</h:body>
</html>
我的ManagedBean
package beans;
import java.util.ArrayList;
import javax.enterprise.context.RequestScoped;
import javax.faces.bean.ManagedBean;
import javax.inject.Named;
import model.Match;
import model.Stats;
import model.User;
@Named
@ManagedBean
@RequestScoped
public class MainBean {
private ArrayList<User> userarray = new ArrayList();
private ArrayList<Stats> statsarray = new ArrayList();
private ArrayList<Match> matcharray = new ArrayList();
public ArrayList<User> getUserarray() {
return userarray;
}
public void setUserarray(ArrayList<User> userarray) {
this.userarray = userarray;
}
public ArrayList<Stats> getStatsarray() {
return statsarray;
}
public void setStatsarray(ArrayList<Stats> statsarray) {
this.statsarray = statsarray;
}
public ArrayList<Match> getMatcharray() {
return matcharray;
}
public void setMatcharray(ArrayList<Match> matcharray) {
this.matcharray = matcharray;
}
public int getAllKills(User u) {
int kills = 0;
for (Stats stats : statsarray) {
if (u.getdiscordId() == stats.getdiscordUserId()) {
kills = kills + stats.getKills();
}
}
return kills;
}
public int getAllDeaths(User u) {
int deaths = 0;
for (Stats stats : statsarray) {
if (u.getdiscordId() == stats.getdiscordUserId()) {
deaths = deaths + stats.getDeaths();
}
}
return deaths;
}
public void fillArrays() {
userarray = service.Service.getAllUsersFromDB();
}
}
解决方法
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