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

  1. Method expression (JSF 2.0)
  2. f:param
  3. f:attribute
  4. 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…

<h:commandButton action="#{user.editAction(delete)}" />

Backing bean…

@ManagedBean(name="user")
@SessionScoped
public 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 – JSF 2.0 method expression caused error in Tomcat.

2. f:param

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

JSF page…

<h:commandButton action="#{user.editAction}">
	<f:param name="action" value="delete" />
</h:commandButton>

Backing bean…

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

See a full f:param example here.

3. f:atribute

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

JSF page…

<h:commandButton action="#{user.editAction}" actionListener="#{user.attrListener}"> 
	<f:attribute name="action" value="delete" />
</h:commandButton>

Backing bean…

@ManagedBean(name="user")
@SessionScoped
public 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 f:attribute example here.

4. f:setPropertyActionListener

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

JSF page…

<h:commandButton action="#{user.editAction}" >
    <f:setPropertyActionListener target="#{user.action}" value="delete" />
</h:commandButton>

Backing bean…

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

See a full f:setPropertyActionListener example here.

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

Tags :
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