Primefaces下拉依赖项

Question

请参阅此primefaces下拉链接https://www.primefaces.org/showcase/ui/ajax/dropdown.xhtml，我已经用它来成功建立国家和州关系。我刚刚被要求添加一个城市作为对状态的另一个依赖，我想知道如何构建城市的hashmap？

有人能给我一些帮助吗？我非常喜欢primefaces，jsf和hibernator以及所有这些，非常感谢你能帮助我看看这个。

Primefaces 3.4.2，JSF2.1.29

public void onCountryChange() {
    if(country !=null && !country.equals(""))
        cities = data.get(country);
    else
        cities = new HashMap<String, String>();
}


<h:form>
<p:growl id="msgs" showDetail="true" />

<p:panel header="Select a Location" style="margin-bottom:10px;">
    <h:panelGrid columns="2" cellpadding="5">
        <p:outputLabel for="country" value="Country: " />
        <p:selectOneMenu id="country" value="#{dropdownView.country}" style="width:150px">
            <p:ajax listener="#{dropdownView.onCountryChange}" update="city" />
            <f:selectItem itemLabel="Select Country" itemValue="" noSelectionOption="true" />
            <f:selectItems value="#{dropdownView.countries}" />
        </p:selectOneMenu>

        <p:outputLabel for="city" value="City: " />
        <p:selectOneMenu id="city" value="#{dropdownView.city}" style="width:150px">
            <f:selectItem itemLabel="Select City" itemValue="" noSelectionOption="true" />
            <f:selectItems value="#{dropdownView.cities}" />
        </p:selectOneMenu>
    </h:panelGrid>

    <p:separator />

    <p:commandButton value="Submit" update="msgs" actionListener="#{dropdownView.displayLocation}" icon="ui-icon-check" />
</p:panel>

@ManagedBean
@ViewScoped
public class DropdownView implements Serializable {

private Map<String,Map<String,String>> data = new HashMap<String, Map<String,String>>();
private String country; 
private String city;  
private Map<String,String> countries;
private Map<String,String> cities;

@PostConstruct
public void init() {
    countries  = new HashMap<String, String>();
    countries.put("USA", "USA");
    countries.put("Germany", "Germany");
    countries.put("Brazil", "Brazil");

    Map<String,String> map = new HashMap<String, String>();
    map.put("New York", "New York");
    map.put("San Francisco", "San Francisco");
    map.put("Denver", "Denver");
    data.put("USA", map);

    map = new HashMap<String, String>();
    map.put("Berlin", "Berlin");
    map.put("Munich", "Munich");
    map.put("Frankfurt", "Frankfurt");
    data.put("Germany", map);

    map = new HashMap<String, String>();
    map.put("Sao Paolo", "Sao Paolo");
    map.put("Rio de Janerio", "Rio de Janerio");
    map.put("Salvador", "Salvador");
    data.put("Brazil", map);
}

Answer 1

我想我得上班了：

    countries1  = new HashMap<String, String>();
    countries1.put("USA", "USA");
    countries1.put("Malaysia", "Malaysia");

    Map<String,String> map = new HashMap<String, String>();
    map.put("Washington", "Washington");
    map.put("California", "California");
    data.put("USA", map);

    map = new HashMap<String, String>();
    map.put("Johor", "Johor");
    map.put("Penang", "Penang");
    data.put("Malaysia", map);

    Map<String,String> map1 = new HashMap<String, String>();
    map1.put("Washington City1", "Washington City1");
    map1.put("Washington City2", "Washington City2");
    data1.put("Washington", map1);

    map1 = new HashMap<String, String>();
    map1.put("California City1", "California City1");
    map1.put("California City2", "California City2");
    data1.put("California", map1);

    map1 = new HashMap<String, String>();
    map1.put("Johor City1", "Johor City1");
    map1.put("Johor City2", "Johor City2");
    data1.put("Johor", map1);

    map1 = new HashMap<String, String>();
    map1.put("Penang City1", "Penang City1");
    map1.put("Penang City2", "Penang City2");
    data1.put("Penang", map1);

-

<h:outputLabel for="country_id1" value="#{msg.countryLabel}: *" />
                <p:selectOneMenu id="country_id1" value="#{userBean.country1}"
                    style="width:150px">
                    <p:ajax listener="#{userBean.onCountryChange}" update="state2" />
                    <f:selectItem itemLabel="Select Country" itemValue=""
                        noSelectionOption="false" />
                    <f:selectItems value="#{userBean.countries1}" />
                </p:selectOneMenu>
                <p:message for="country_id1" />

                <h:outputLabel for="state2" value="State: *" />
                <p:selectOneMenu id="state2" value="#{userBean.state}"
                    style="width:150px">
                    <p:ajax listener="#{userBean.onStateChange}" update="city22" />
                    <f:selectItem itemLabel="Select State" itemValue=""
                        noSelectionOption="false" />
                    <f:selectItems value="#{userBean.states}" />
                </p:selectOneMenu>
                <p:message for="state2" />

                <h:outputLabel for="city22" value="City: *" />
                <p:selectOneMenu id="city22" value="#{userBean.city1}"
                    style="width:150px">
                    <f:selectItem itemLabel="Select City" itemValue=""
                        noSelectionOption="true" />
                    <f:selectItems value="#{userBean.cities1}" />
                </p:selectOneMenu>

public void onCountryChange() {
    lg.info("country in change: " + country1);

    if (country1 != null && !country1.equals("")) {
        states = data.get(country1);
    }
    else
        states = new HashMap<String, String>();
}

public void onStateChange() {
    lg.info("state in change: " + state);

    if (state != null && !state.equals("")) {
        cities1 = data1.get(state);
    }
    else
        cities1 = new HashMap<String, String>();
}