JSFParameter

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 :

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…

<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");
      //...

}

} 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" }

}