我一般在vaadin框架上有问题。

我创建了一个类来扩展vaadin应用程序（MyFirst），然后用vaadin可视设计器（MyFormApp）创建了一个自定义组件。

我确实实例化了自定义组件MyFormApp，并将其添加到MyFirst的主窗口中。

部署应用程序后，vaadin生成的页面未显示任何组件。

我的代码：

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package com.example.vaadin;

import com.vaadin.Application;
import com.vaadin.ui.*;

/**
*
* @author anis.bouchenafa
*/
public class MyFirst extends Application{


private Button newContact = new Button("Add contact");
private Button search = new Button("Search");
private Button share = new Button("Share");
private Button help = new Button("Help");
private HorizontalSplitPanel horizontalSplit = new HorizontalSplitPanel();
private TextField tf = new TextField();

@Override
public void init() {
    //buildMainLayout();

    MyFirstApp a = new MyFirstApp();
   Window w = new Window("aness conf");
   w.addComponent(a);
   setMainWindow(w);


}

}

我的第二堂课是MyFirstApp（自定义组件）：

package com.example.vaadin;



import com.vaadin.annotations.AutoGenerated;
import com.vaadin.ui.AbsoluteLayout;
import com.vaadin.ui.CustomComponent;
import com.vaadin.ui.LoginForm;

public class MyFirstApp extends CustomComponent {

@AutoGenerated
private AbsoluteLayout mainLayout;
@AutoGenerated
private LoginForm loginForm_2;

/*- VaadinEditorProperties=        {"grid":"RegularGrid,20","showGrid":true,"snapToGrid":true,"snapToObject":true,"movingGuides":false,"snappingDistance":10} */



/*- VaadinEditorProperties={"grid":"RegularGrid,20","showGrid":true,"snapToGrid":true,"snapToObject":true,"movingGuides":false,"snappingDistance":10} */

/**
 * The constructor should first build the main layout, set the
 * composition root and then do any custom initialization.
 *
 * The constructor will not be automatically regenerated by the
 * visual editor.
 */
public MyFirstApp() {
    buildMainLayout();
    setCompositionRoot(mainLayout);

    // TODO add user code here
}

@AutoGenerated
private AbsoluteLayout buildMainLayout() {
    // common part: create layout
    mainLayout = new AbsoluteLayout();
    mainLayout.setImmediate(false);
    mainLayout.setWidth("100%");
    mainLayout.setHeight("100%");

    // top-level component properties
    setWidth("100.0%");
    setHeight("100.0%");

    // loginForm_2
    loginForm_2 = new LoginForm();
    loginForm_2.setStyleName("v-loginform");
    loginForm_2.setImmediate(false);
    loginForm_2.setWidth("340px");
    loginForm_2.setHeight("-1px");
    mainLayout.addComponent(loginForm_2, "top:160.0px;left:200.0px;");

    return mainLayout;
}

}

在执行servlet之后，浏览器中没有任何显示。