Question

我正在使用J2EE和Glassfish开始我的第一步。我正在试验the examples from the J2EE 6 tutorial，更具体地说是“hello1”。

我有以下bean：

@ManagedBean(eager=true)
@ApplicationScoped
public class Hello {
    private String name;
    private Logger log = Logger.getLogger(Hello.class.getName()); 

    public Hello() {
        log.info("Ctor: Hello has been created" + this.getClass().getName()); 
    }

    @PostConstruct
    public void postConstruct() {
        log.info("postConstruct() " + this.getClass().getName()); 
    }

    public String getName() {
        return name;
    }

    public void setName(String user_name) {
        this.name = user_name;
    }
}

以下XHTML：

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html">
    <h:head>
        <title>Facelets Hello Greeting</title>
    </h:head>
    <h:body>
        <h:form>
            <h:graphicImage url="duke.waving.gif"/>
            <h2>Hello, my name is Duke. What's yours?</h2>
            <h:inputText id="username" 
                         value="#{hello.name}"
                         required="true"
                         requiredMessage="A name is required."
                         maxlength="25">
            </h:inputText>
            <p></p>
            <h:commandButton id="submit" value="Submit" action="response">
            </h:commandButton>
            <h:commandButton id="reset" value="Reset" type="reset">
            </h:commandButton>
        </h:form>
    </h:body>
</html>

应用程序正在运行，但显然创建了bean的多个实例：

2014-03-27T11:23:44.077+0100|Information: Ctor: Hello has been createdhello1.Hello
2014-03-27T11:23:44.077+0100|Information: postConstruct() hello1.Hello
2014-03-27T11:23:46.713+0100|Information: Ctor: Hello has been createdhello1.Hello
2014-03-27T11:23:46.713+0100|Information: postConstruct() hello1.Hello
2014-03-27T11:23:49.112+0100|Information: Ctor: Hello has been createdhello1.Hello
2014-03-27T11:23:49.112+0100|Information: postConstruct() hello1.Hello

起初我认为创建了代理，这就是我在日志中添加this.getClass().getName()的原因，但事实并非如此。此外，hello.name不在实例之间共享。

从我可以阅读的所有文档和示例中，@ApplicationScoped应该在应用程序级别创建一个单例。此外，eager=trye无法按预期工作，因为在应用程序启动时未创建任何实例。我做错了什么？

Answer 1

发出问题一分钟后，我发现了问题。正如Adarsh所怀疑的那样，我正在导入javax.enterprise.context.ApplicationScoped而不是javax.faces.bean.ApplicationScoped

@ApplicationScoped没有预期的效果

1 个答案: