Setting a bean property from a request parameter

Question

What is the correct (best) way to set a managed bean's property from a request's parameter?

The URL for my JSF page looks something like this:

https://eample.com/app/faces/page.xhtml?ts=2012-01-05T10:00:00.000

I have found that I can read the parameter using the following:

<h:outputText value="#{param['ts']}" />

But what I really need to do is set my bean's property from this value. So what is the best JSF way code this so I get something which results Java code like this:

myBean.setTimestamp(request.getParameter("timestamp"));

Many thanks

score 1 · Accepted Answer · answered Jan 07 '13 at 12:35

Assuming a JSF managed bean with request scope, inject it as a managed property:

import javax.faces.bean.*;

@ManagedBean @RequestScoped
public class ReqBean {
    @ManagedProperty("#{param.ts}") private String ts;

    public String getTs() {
        return ts;
    }

    public void setTs(String ts) {
        this.ts = ts;
    }
}

If the bean is in a broader scope, you will need to look it up programmatically:

private String lookUpTs() {
    return FacesContext.getCurrentInstance()
                       .getExternalContext()
                       .getRequestParameterMap()
                       .get("ts");
}

If you are using CDI beans, you will need to consider other options (see here for one approach.)

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

Based on your question history, you're using JSF2, so just the <f:viewParam> should do.

<f:metadata>
    <f:viewParam name="ts" value="#{myBean.timestamp}" />
</f:metadata>

That's it.

As <f:viewParam> extends from UIInput (like <h:inputText> and so on), you can even perform conversion and validation on it using e.g. <f:convertDateTime> and required="true".

<f:metadata>
    <f:viewParam id="ts" name="ts" value="#{myBean.timestamp}" required="true">
        <f:convertDateTime pattern="yyyy-MM-dd'T'HH:mm:ss.SSS" />
    </f:viewParam>
</f:metadata>
...
<h:message for="ts" />

This way the #{myBean.timestamp} can be a fullworthy java.util.Date property. Any conversion and validation errors will end up in the <h:message> associated with <f:viewParam id>.

Note that unlike with @ManagedProperty, the #{myBean} can just be a @ViewScoped one.

Setting a bean property from a request parameter

2 Answers2

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