4 ways to pass parameter from JSF page to backi...-白红宇

4 ways to pass parameter from JSF page to backi...

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发布时间：2019-06-22

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As i know,there are 4 ways to pass a parameter value from JSF page to backing bean :

Method expression (JSF 2.0)

f:param

f:attribute

f:setPropertyActionListener

Let see example one by one :

1. Method expression

Since JSF 2.0, you are allow to pass parameter value in the method expression like this #{bean.method(param)}.

JSF page…

Backing bean…

@ManagedBean(name="user") @SessionScopedpublic class UserBean{
          	public String editAction(String id) {
         	  //id = "delete" 	}  }

Note

If you are deploy JSF application in servlet container like Tomcat, make sure you include the “

el-impl-2.2.jar” properly. For detail, please read this article – .

2. f:param

Pass parameter value via f:param tag and get it back via request parameter in backing bean.

JSF page…

Backing bean…

@ManagedBean(name="user") @SessionScopedpublic class UserBean{
          	public String editAction() {
          	  Map
       
         params =                 FacesContext.getExternalContext().getRequestParameterMap(); 	  String action = params.get("action");           //...  	}  }

See a full here.

3. f:atribute

Pass parameter value via f:atribute tag and get it back via action listener in backing bean.

JSF page…

Backing bean…

@ManagedBean(name="user") @SessionScopedpublic class UserBean{
            String action;    //action listener event   public void attrListener(ActionEvent event){
          	action = (String)event.getComponent().getAttributes().get("action");    }    public String editAction() {
         	//...   }	 }

See a full here.

4. f:setPropertyActionListener

Pass parameter value via f:setPropertyActionListener tag, it will set the value directly into your backing bean property.

JSF page…

Backing bean…

@ManagedBean(name="user") @SessionScopedpublic class UserBean{
          	public String action;  	public void setAction(String action) {
         		this.action = action; 	}  	public String editAction() {
         	   //now action property contains "delete" 	}	 }

See a full here.

P.S Please share your idea, if you have any other ways :)

转载于:https://my.oschina.net/yida/blog/69615

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