jsf getting to request parameters inside bean

Question

i am aware that this has been discussed before, but the example that i created does not work.

bean:

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.context.*;

import java.io.Serializable;
import java.util.Map;

@ManagedBean
@SessionScoped
public class HelloBean implements Serializable {

private static final long serialVersionUID = 1L;

private String name;

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String submit() {
    FacesContext fc = FacesContext.getCurrentInstance();
    Map<String,String> params = 
            fc.getExternalContext().getRequestParameterMap();
    System.out.println("params" + params);

        String country = params.get("country");
        System.out.println("country:" + country);

    return "welcome";
}
}

and this is the page:

</h:head>
<h:body>
    <h:outputScript library="js" name="common.js" />
    <!--  <h:outputScript library="js" name="websocket.js" /> -->
<h3>JSF 2.0 Hello World Example - hello.xhtml</h3>
<h:form>
    <h:inputText value="#{helloBean.name}"></h:inputText>
    <h:commandButton value="Welcome Me"  action="#{helloBean.submit}">    </h:commandButton> 
</h:form>



</h:body>
</html>

when i call the page like this: localhost:8080/JavaServerFaces2/hello.xhtml?country=123

and press the button i would expect that the submit method prints the country value in the console. but it prints:

2018-05-13T17:06:48.872+0200|Info: params{j_idt7=j_idt7, j_idt7:j_idt8=,    j_idt7:j_idt9=Welcome Me, javax.faces.ViewState=-   4186994023180961740:1040096002697043710}
2018-05-13T17:06:48.872+0200|Info: country:null

why?

p.s. im eagerly awaiting the new feature to paste code, im sure it will be great.

Because you've got different requests, the first one when you GET the page and the other one when you POST it. And you're not keeping the parameter anywhere. — Aritz, May 13 '18 at 16:29
ah ok, so reading the parameters in submit() is to late. where else would one do that? — James Baker, May 13 '18 at 17:21
Possible duplicate of [Retaining GET request query string parameters on JSF form submit](https://stackoverflow.com/questions/17734230/retaining-get-request-query-string-parameters-on-jsf-form-submit) — Aritz, May 13 '18 at 17:24

score 0 · Answer 1 · answered May 13 '18 at 17:40

0

changing the form in the .xhtml to this:

<h:form>
    <h:inputText value="#{helloBean.name}"></h:inputText>
    <h:commandButton value="Welcome Me"  action="#{helloBean.submit}"> 
    <f:param name="country" value="#{param.country}" />
    </h:commandButton>
</h:form>

and the request parameter is preserved from the first page view and it shows up in the console

answered May 13 '18 at 17:40

James Baker

107
2
11

is there maybe also a way to act on the parameters when the page is first loaded? using: @PostConstruct public void init(){ x } where x is the code from the submit() above without the return does not work. nothing is printed on the console – James Baker May 13 '18 at 18:19
sure just parse requestscoped parameters like in many other Q/A in stackoverflow – Kukeltje May 14 '18 at 06:01

jsf getting to request parameters inside bean

1 Answers1