我想编写一个 Vaadin 7 应用程序(参见下面的MyVaadinUI),它要求用户输入用户名和密码。
如果它们是正确的,应该出现另一个视图(见下面的MainUI)并占据整个区域(替换登录视图)。
我尝试在MyVaadinUI.goToMainWindow方法中实现此转换,但出现错误
java.lang.RuntimeException: Component must be attached to a session when getConnectorId() is called for the first time
at com.vaadin.server.AbstractClientConnector.getConnectorId(AbstractClientConnector.java:417)
at com.vaadin.server.communication.ConnectorHierarchyWriter.write(ConnectorHierarchyWriter.java:67)
at com.vaadin.server.communication.UidlWriter.write(UidlWriter.java:143)
at com.vaadin.server.communication.UidlRequestHandler.writeUidl(UidlRequestHandler.java:149)
at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:97)
at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:37)
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1371)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:238)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
当我运行应用程序并按下按钮时。
我该如何解决?
@Theme("mytheme")
@SuppressWarnings("serial")
public class MyVaadinUI extends UI
{
private TextField userNameTextField;
private PasswordField passwordTextField;
@WebServlet(value = "/*", asyncSupported = true)
@VaadinServletConfiguration(productionMode = false, ui = MyVaadinUI.class, widgetset = "ru.mycompany.vaadin.demo.AppWidgetSet")
public static class Servlet extends VaadinServlet {
}
@Override
protected void init(VaadinRequest request) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin(true);
setContent(layout);
addUserNameTextField(layout);
addPasswordTextField(layout);
addButton(layout, request);
}
private void addPasswordTextField(Layout aLayout) {
passwordTextField = new PasswordField("Пароль:");
aLayout.addComponent(passwordTextField);
}
private void addUserNameTextField(final Layout aLayout) {
userNameTextField = new TextField("Пользователь:");
aLayout.addComponent(userNameTextField);
}
private void addButton(final Layout aParent, final VaadinRequest request) {
final Button button = new Button("Войти");
button.addClickListener(new Button.ClickListener() {
public void buttonClick(Button.ClickEvent event) {
final boolean credentialsCorrect = checkCredentials();
if (credentialsCorrect) {
goToMainWindow(request);
} else {
[...]
}
}
});
aParent.addComponent(button);
}
private void goToMainWindow(final VaadinRequest aRequest) {
final MainUI mainUI = new MainUI();
mainUI.init(aRequest);
setContent(mainUI);
}
}
@Theme("mytheme")
@SuppressWarnings("serial")
public class MainUI extends UI {
@Override
protected void init(final VaadinRequest vaadinRequest) {
final HorizontalSplitPanel splitPanel = new HorizontalSplitPanel();
setContent(splitPanel);
splitPanel.setSizeFull();
splitPanel.setSplitPosition(200, Unit.PIXELS);
final String[] tabLabels = new String[] {
"Tree item 1",
"Tree item 2"};
final Tree tree = new Tree();
for (int i=0; i < tabLabels.length; i++)
{
addTreeItem(tree, tabLabels[i]);
}
splitPanel.setFirstComponent(tree);
splitPanel.setSecondComponent(new Label("Test"));
}
private void addTreeItem(final Tree aTree, final String aLabel) {
aTree.addItem(aLabel);
}
}