Question

我是Vaadin的新手，我正在尝试在我的UI类中注入@UIScoped - bean。但它每次都会抛出NullPointerException - 为什么？

这是我的UI类：

import javax.inject.Inject;

import org.apache.log4j.Logger;

import com.vaadin.annotations.Theme;
import com.vaadin.cdi.CDIUI;
import com.vaadin.server.VaadinRequest;
import com.vaadin.ui.Label;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@SuppressWarnings("serial")
@Theme("tableuitheme")
@CDIUI("")
public class Table extends UI {

    private final static Logger logger=Logger.getLogger(Table.class); 

    @Inject
    private SomeBean bean;

    @Override
    protected void init(VaadinRequest request) {



        VerticalLayout layout = new VerticalLayout();
        setContent(layout);

        logger.info("-------------------------- "+bean); 

//      String art = hakan.toString();

        Label label = new Label("Hakan");

        layout.addComponents(label);

    }

}

这是界面SomeBean：

public interface SomeBean {
}

和实现类SomeBeanImpl：

import com.vaadin.cdi.UIScoped;

@UIScoped
public class SomeBeanimpl implements SomeBean {

}

最后是我的配置文件：

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_0.xsd">
    <servlet>
        <servlet-name>myVaadinUIServlet</servlet-name>
        <servlet-class>com.vaadin.server.VaadinServlet</servlet-class>
        <init-param>
            <param-name>UI</param-name>
            <param-value>de.ragms.ui.Table</param-value>
        </init-param>
        <async-supported>true</async-supported>
    </servlet>

    <context-param>
        <description>Vaadin production mode</description>
        <param-name>productionMode</param-name>
        <param-value>false</param-value>
    </context-param>
    <servlet-mapping>
        <servlet-name>myVaadinUIServlet</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
</web-app>

bean.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://java.sun.com/xml/ns/javaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
</beans>

Vaadin中的CDi没有注入：NullPointerException

0 个答案: