h：commandButton操作仅在两次调用中被调用一次

问题描述

| 我在Web应用程序上使用JSF 1.2。在我的页面test.xhtml中，我有一个包含如下commandButton的表单：

<h:form>
  <h:commandButton action=\"#{myBean.myMethod}\" value=\"Call my method\" />
</h:form>

在java源代码中，我的bean是这样的：

public class MyBean {
  public void myMethod() {
    System.out.println(\"my method called\");
  }
}

当我显示页面test.xhtml时，第一次单击命令按钮时，该动作已被很好地调用。页面已刷新。然后，我尝试单击命令按钮，但未调用该操作。就像JSF Lifecycle是否直接进入RENDER_RESPONSE阶段而不调用INVOKE_APPLICATION阶段一样。 页面会刷新，然后单击时会很好地调用该动作。因此，该动作被两次调用一次。 为了理解，我非常简单地添加了一个阶段监听器：

public class MyPhaseListener implements PhaseListener{

public PhaseId getPhaseId() {
    return PhaseId.ANY_PHASE;
}

public void beforePhase(PhaseEvent event) {
    System.out.println(\"START PHASE \" + event.getPhaseId());
}

public void afterPhase(PhaseEvent event) {
    System.out.println(\"END PHASE \" + event.getPhaseId());
}}

当我运行测试时，请单击我的页面，输出如下：

START PHASE RESTORE_VIEW 1
END PHASE RESTORE_VIEW 1
START PHASE APPLY_REQUEST_VALUES 2
END PHASE APPLY_REQUEST_VALUES 2
START PHASE PROCESS_VALIDATIONS 3
END PHASE PROCESS_VALIDATIONS 3
START PHASE UPDATE_MODEL_VALUES 4
END PHASE UPDATE_MODEL_VALUES 4
START PHASE INVOKE_APPLICATION 5
my method called
END PHASE INVOKE_APPLICATION 5
START PHASE RENDER_RESPONSE 6
END PHASE RENDER_RESPONSE 6

START PHASE RESTORE_VIEW 1
END PHASE RESTORE_VIEW 1
START PHASE RENDER_RESPONSE 6
END PHASE RENDER_RESPONSE 6

START PHASE RESTORE_VIEW 1
END PHASE RESTORE_VIEW 1
START PHASE APPLY_REQUEST_VALUES 2
END PHASE APPLY_REQUEST_VALUES 2
START PHASE PROCESS_VALIDATIONS 3
END PHASE PROCESS_VALIDATIONS 3
START PHASE UPDATE_MODEL_VALUES 4
END PHASE UPDATE_MODEL_VALUES 4
START PHASE INVOKE_APPLICATION 5
my method called
END PHASE INVOKE_APPLICATION 5
START PHASE RENDER_RESPONSE 6
END PHASE RENDER_RESPONSE 6

START PHASE RESTORE_VIEW 1
END PHASE RESTORE_VIEW 1
START PHASE RENDER_RESPONSE 6
END PHASE RENDER_RESPONSE 6

通过使用PhaseListener，我可以清楚地看到，在每次生命周期的第二次调用中，生命周期都会直接进入RESTORE_VIEW阶段到RENDER_RESPONSE，而无需我对生命周期进行任何操作。 有人会想到避免这种情况，并在该页面上每次执行生命周期吗？还是每次我单击命令按钮时都执行操作的解决方案？ 就像您告诉我的一样，我在打印上添加了一些调试信息，例如UIViewRoot对象和会话ID。现在，操作顺序将提供以下信息：

START PHASE RESTORE_VIEW 1
UIViewRoot :null
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RESTORE_VIEW 1
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE APPLY_REQUEST_VALUES 2
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE APPLY_REQUEST_VALUES 2
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE PROCESS_VALIDATIONS 3
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE PROCESS_VALIDATIONS 3
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE UPDATE_MODEL_VALUES 4
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE UPDATE_MODEL_VALUES 4
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE INVOKE_APPLICATION 5
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
my method called
END PHASE INVOKE_APPLICATION 5
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7cbcb4
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7


START PHASE RESTORE_VIEW 1
UIViewRoot :null
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RESTORE_VIEW 1
UIViewRoot :javax.faces.component.UIViewRoot@7cbaea
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7cbaea
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7cbaea
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7


START PHASE RESTORE_VIEW 1
UIViewRoot :null
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RESTORE_VIEW 1
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE APPLY_REQUEST_VALUES 2
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE APPLY_REQUEST_VALUES 2
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE PROCESS_VALIDATIONS 3
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE PROCESS_VALIDATIONS 3
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE UPDATE_MODEL_VALUES 4
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE UPDATE_MODEL_VALUES 4
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE INVOKE_APPLICATION 5
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
my method called
END PHASE INVOKE_APPLICATION 5
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7ccfa1
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7


START PHASE RESTORE_VIEW 1
UIViewRoot :null
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RESTORE_VIEW 1
UIViewRoot :javax.faces.component.UIViewRoot@7cac2f
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
START PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7cac2f
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7
END PHASE RENDER_RESPONSE 6
UIViewRoot :javax.faces.component.UIViewRoot@7cac2f
Session ID : 8385AC329B4C75AB4FBCA2CE1FBDFDC7

每个调用序列之间的会话始终相同。因此，我认为这不是UIViewRoot的问题。我还有其他方法可以测试该问题吗？ 西尔万     

解决方法

如果您尚未阅读此博客文章，则应该：http://balusc.blogspot.com/2006/09/debug-jsf-lifecycle.html 由于UIViewRoot不存在，因此您似乎丢失了会话，因此没有要还原的UIViewRoot。