4 ways to pass parameter from JSF page to backing bean

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"
    }

}

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");
          //...

    }

}

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() {
    //...
  }    

}

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"
    }    

}