将参数传递给ViewScoped Bean [英] Pass Parameter to ViewScoped Bean

问题描述

我将参数从一页(Facelet)传递给范围为View Scope的Managed Bean.

I'm going to pass a parameter from one page (Facelet) to a Managed Bean whose scope is View Scope.

我尝试这样做:

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;

@ManagedBean
@ViewScoped
public class Mybean {
  private int id;


  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }    
}

第一页:

  <h:body>            
    <h:form>
      <h:commandLink value="click" action="index">
        <f:setPropertyActionListener target="#{mybean.id}" value="20"/>
      </h:commandLink>
    </h:form>
  </h:body>

第二页:

  <h:body>
    param value #{param.id}
    <br />
    bean value #{mybean.id}
    <br />

    <h:messages/>
  </h:body>

但它不显示20

推荐答案

@ViewScoped bean仅保留用于用户正在观看的视图.

@ViewScoped bean stays only for the view that the user is watching.

一旦用户切换到另一个视图-Bean将被销毁并从头开始创建. 因此，如果您想将同一个bean用于多个页面，请使用@SessionScoped bean.

Once the user switched to another view - the bean is being destroyed and created from scratch. Therefore, if you want to use the same bean for more than one page - use @SessionScoped bean.

另一种方法是用Java创建一个Singleton类，一个bean将更新该类中的值，而另一个bean将从中提取值.

Another way, is to create a Singleton class in Java, and one bean will update the value in this class, while the other bean will extract the value from it.

这篇关于将参数传递给ViewScoped Bean的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！