我尝试在primefaces 5.1上生成一个commandButton，但是我有一个错误：
这里是xhtml文件：
<h:head>
</h:head>
<h:body styleClass="appDefaultBg">
<h:form>
<p:remoteCommand autoRun="true" action="#{bean.pageRender()}" update=":pageElement" />
</h:form>
<h:panelGroup id="pageElement">
</h:panelGroup>
</h:body>
这里是bean类：
@ManagedBean(name = "bean")
@SessionScoped
public class Bean implements Serializable {
private static final String PAGE_ELEMENT = "pageElement";
private UIComponent page;
@PostConstruct
public void init() {
findComponent();
}
public void findComponent() {
FacesContext.getCurrentInstance().getViewRoot().invokeOnComponent(FacesContext.getCurrentInstance(), PAGE_ELEMENT, new ContextCallback() {
@Override
public void invokeContextCallback(FacesContext context, UIComponent component) {
page = component;
}
});
}
public void pageRender() {
HtmlForm form = new HtmlForm();
Panel panel = new Panel();
panel.setId("filter");
panel.setHeader("Header");
CommandButton customButton = new CommandButton();
customButton.setValue("Click me!");
customButton.addActionListener(new CustomActionListener(5));
panel.getChildren().add(customButton);
form.getChildren().add(panel);
page.getChildren().add(form);
}
}
这里是CustomActionListener：
public class CustomActionListener implements ActionListener {
private int u;
public CustomActionListener(int u) {
this.u = u;
}
@Override
public void processAction(ActionEvent event) throws AbortProcessingException {
System.out.println(u);
}
}
按下按钮时收到的错误是：
GRAVE: java.lang.InstantiationException: my.package.CustomActionListener
java.lang.IllegalStateException: java.lang.InstantiationException: my.package.CustomActionListener
at javax.faces.component.StateHolderSaver.restore(StateHolderSaver.java:153)
at javax.faces.component.AttachedObjectListHolder.restoreState(AttachedObjectListHolder.java:158)
at javax.faces.component.UIComponentBase.restoreState(UIComponentBase.java:1611)
at com.sun.faces.application.view.StateHolderSaver.restore(StateHolderSaver.java:165)
at com.sun.faces.application.view.FaceletPartialStateManagementStrategy.restoreDynamicAdd(FaceletPartialStateManagementStrategy.java:274)
at com.sun.faces.application.view.FaceletPartialStateManagementStrategy.restoreDynamicActions(FaceletPartialStateManagementStrategy.java:227)
at com.sun.faces.application.view.FaceletPartialStateManagementStrategy.restoreView(FaceletPartialStateManagementStrategy.java:395)
at com.sun.faces.application.StateManagerImpl.restoreView(StateManagerImpl.java:138)
at com.sun.faces.application.view.ViewHandlingStrategy.restoreView(ViewHandlingStrategy.java:123)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.restoreView(FaceletViewHandlingStrategy.java:585)
at com.sun.faces.application.view.MultiViewHandler.restoreView(MultiViewHandler.java:150)
at com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:197)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:121)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.synapsis.catalina.realm.filter.AlertChangePWDBefore.doFilter(AlertChangePWDBefore.java:106)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.synapsis.catalina.realm.filter.SingleLogOnFilter.doFilter(SingleLogOnFilter.java:123)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.synapsis.catalina.realm.filter.DefaultUserFilter.doFilter(DefaultUserFilter.java:118)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.synapsis.sio.ward.usercontext.controller.filter.UserContextFilter.doFilter(UserContextFilter.java:168)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:610)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:339)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.InstantiationException: my.package.CustomActionListener
at java.lang.Class.newInstance(Class.java:359)
at javax.faces.component.StateHolderSaver.restore(StateHolderSaver.java:150)
... 51 more
如果我从构造函数中删除参数，我没有收到此错误。但是我需要将一个参数传递给我的CustomerActionListener。 我该如何解决？
答案 0 :(得分：0)
您需要在CustomActionListener中使用默认构造函数（除了自定义构造函数）。
答案 1 :(得分：0)
忽略奇怪的设计方法（随意问一个关于如何正确实现您possibly incorrectly认为这是正确解决方案的具体功能要求的问题），您可以通过让它实现来解决它Externalizable。这是Serializable的扩展，允许您接管序列化属性的责任。
这是一个启动示例：
public class CustomActionListener implements ActionListener, Externalizable {
private int u;
public CustomActionListener() {
// Keep default c'tor alive for serialization.
}
public CustomActionListener(int u) {
this.u = u;
}
@Override
public void processAction(ActionEvent event) throws AbortProcessingException {
System.out.println(u);
}
@Override
public void writeExternal(ObjectOutput output) throws IOException {
output.writeInt(u);
}
@Override
public void readExternal(ObjectInput input) throws IOException, ClassNotFoundException {
u = input.readInt();
}
}