a4j实现联动菜单（异步）

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本文介绍了一种使用JSF和a4j实现的联动菜单功能，包括异步和同步两种方式。通过设置不同国家对应的可选城市列表，实现了菜单项的选择联动效果。

2008-04-28 16:37

a4j实现联动菜单（异步）

JSF页面：

                        <h:selectOneMenu id="country" value="#{countryCity.country}">
                            <f:selectItems value="#{countryCity.countryName}"/>
                            <a4j:support event="onchange" reRender="city" action="#{countryCity.change}"/>
                        </h:selectOneMenu>
                        <h:selectOneMenu id="city">
                            <f:selectItems value="#{countryCity.currentCityName}"/>
                        </h:selectOneMenu>

backingbean：
public class CountryCity {
    private List<SelectItem> countryName;
    private List<List<SelectItem>> cityName;
    private List<SelectItem> currentCityName;
    private String country;

    public CountryCity(){
        countryName = new ArrayList();
        countryName.add(new SelectItem("0","China"));
        countryName.add(new SelectItem("1","England"));
        countryName.add(new SelectItem("2","America"));

        List<SelectItem> china = new ArrayList();
        china.add(new SelectItem("guangzhou","guangzhou"));
        china.add(new SelectItem("xianggang","xianggang"));

        List<SelectItem> england = new ArrayList();
        england.add(new SelectItem("Londun","Londun"));

        List<SelectItem> america = new ArrayList();
        america.add(new SelectItem("housdun","housdun"));
        america.add(new SelectItem("Washdom","Washdom"));

        cityName = new ArrayList();
        cityName.add(china);
        cityName.add(england);
        cityName.add(america);

        currentCityName = cityName.get(0);
    }

    public List<SelectItem> getCountryName() {
        return countryName;
    }

    public void setCountryName(List<SelectItem> countryName) {
        this.countryName = countryName;
    }

    public List<List<SelectItem>> getCityName() {
        return cityName;
    }

    public void setCityName(List<List<SelectItem>> cityName) {
        this.cityName = cityName;
    }

    public List<SelectItem> getCurrentCityName() {
        return currentCityName;
    }

    public void setCurrentCityName(List<SelectItem> currentCityName) {
        this.currentCityName = currentCityName;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public void change(){
        currentCityName = cityName.get(Integer.parseInt(getCountry()));
    }

}

faces-config.xml声明：

<managed-bean>
    <managed-bean-name>countryCity</managed-bean-name>
    <managed-bean-class>bb.CountryCity</managed-bean-class>
    <managed-bean-scope>session</managed-bean-scope>
</managed-bean>

范围应该设成session，不然会出现bug。

JSF实现联动菜单（同步）：

http://hi.baidu.com/coolcat%5Fpolice/blog/item/77b6013dcf4909c29e3d622f.html