How to dynamically add JSF components

问题

Can I add JSF components dynamically? I need to have a form with a button which should add one <h:inputText> to the form. Is this possible?

I know this should be possible in JavaScript somehow. Do anybody know how to do this in JSF? I think the major problem is how do I get or set values of new inputs via #{value}.

回答1:

Use an iterating component like <h:dataTable> or <ui:repeat> to display a dynamically sized List of entities. Make the bean @ViewScoped to ensure that the list is remembered across postbacks on the same view instead of recreated over and over.

Kickoff example with <h:dataTable> (when using <ui:repeat> simply replace <h:dataTable> by <ui:repeat>, and <h:column> by e.g. <li> or <div>):

<h:form>
    <h:dataTable value="#{bean.items}" var="item">
        <h:column><h:inputText value="#{item.value}" /></h:column>
        <h:column><h:commandButton value="remove" action="#{bean.remove(item)}" /></h:column>
    </h:dataTable>
    <h:commandButton value="add" action="#{bean.add}" />
    <h:commandButton value="save" action="#{bean.save}" />
</h:form>

Managed bean:

@ManagedBean
@ViewScoped
public class Bean {

    private List<Item> items;

    @PostConstruct
    public void init() {
        items = new ArrayList<Item>();
    }

    public void add() {
        items.add(new Item());
    }

    public void remove(Item item) {
        items.remove(item);
    }

    public void save() {
        System.out.println("items: " + items);
    }

    public List<Item> getItems() {
        return items;
    }

}

Model:

public class Item {

    private String value;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String toString() {
        return String.format("Item[value=%s]", value);
    }

}

See also:

• Recommended JSF 2.0 CRUD frameworks
• How to create dynamic JSF form fields
• How to implement a dynamic list with a JSF 2.0 Composite Component?
• How to choose the right bean scope?

回答2:

It's should be like that

Bind a form tag to the bean property

<form binding="#{myBean.myform}">...</form>

@ManagedBean("myBean")
public class Bean{
   property HtmlForm myform;
}

on event, create a new instance of the input component

HtmlInputText input=new HtmlInputText();

and attach to the your form

myform.getChildren().add(input);

回答3:

Use h:dataTable to add elements dynamically... Have a list of any type you want to provide values for dataTable...

In h:dataTable... you can include the element tag to create inside <h:column>

It will be used to generate elements you want to create dynamically.

来源：https://stackoverflow.com/questions/3409053/how-to-dynamically-add-jsf-components