我正在尝试为单个会话bean提供一个基本模板。然后,我以“柜台的体系结构”中包含的示例为例:

https://docs.oracle.com/javaee/7/tutorial/ejb-basicexamples002.htm

但是,在运行示例时,我无法打印count.hitCount的值。

我发现访问变量时没有getter的常见问题。例如,在index.html中:

<ui:define name="title">
        This page has been accessed #{count.hitCount} time(s).
</ui:define>


但是,在Count.java中包括getter getHitCount():

@Named
@SessionScoped
public class Count implements Serializable {

    @EJB
    private CounterBean counterBean;

    private int hitCount;

    public Count() {
        this.hitCount = 0;
    }

    public int getHitCount() {
        hitCount = counterBean.getHits();
        return hitCount;
    }
    public void setHitCount(int newHits) {
        this.hitCount = newHits;
    }


最后,CounterBean.java增加变量:

@Singleton
public class CounterBean {
    private int hits = 1;

    // Increment and return the number of hits
    public int getHits() {
        return hits++;
    }
}


感谢您的帮助和评论,我们非常感谢。

最佳答案

具有显示时间的计数器的facelet:

<?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://xmlns.jcp.org/jsf/html">
  <h:head>
    <title>Facelet Title</title>
</h:head>
  <h:body>
    This page displayed #{counterController.hitCount} times.
  </h:body>
</html>


CounterController是一个@RequestScoped bean,用于通过其CounterBean.hitCount方法增加@PostConstruct

package x;

import javax.annotation.PostConstruct;
import javax.ejb.EJB;
import javax.inject.Named;
import javax.enterprise.context.RequestScoped;

@Named( value = "counterController" )
@RequestScoped
public class counterController
{

  @EJB
  private CounterBean counterBean;

  @PostConstruct
  public void initialize()
  {
    counterBean.incHitCount();
  }

  public int getHitCount()
  {
    return counterBean.getHitCount();
  }

  public CounterController()
  {
  }

}


CounterBean是用于存储hitCount的@Singleton EJB。 @StartUp批注将其构造为一个热切构造的bean(在启动任何客户端请求之前在应用程序启动时创建):

package x;

import javax.ejb.Singleton;
import javax.ejb.Startup;
import lombok.Data;

@Singleton
@Startup
public class CounterBean
{
  private int hitCount;

  public int getHitCount()
  {
    return hitCount;
  }

  public void incHitCount()
  {
    hitCount++;
  }

  public CounterBean()
  {}
}

07-24 15:30