填充chlid jSF selectOneMenu - 隱式值驗證錯誤

Question

正如您在屏幕截圖中看到的，我對屬性“member.city”有一個JSF隱式值驗證錯誤 。 目的是通過ajax - 在上一個Country Select one菜單上選擇一個國家后填充城市選擇一個菜單。 這是通過使用selectOneMenu更改偵聽器和ajax來更新顯示城市列表的組件來實現的。 但是，我收到驗證錯誤，表單未提交。

我嘗試使用和不使用實體（hascode和equals方法） ，但是徒勞無功。 我使用分離的Managed Bean ViewScoped來檢索已過濾的列表，但是徒勞無功。 **

如果我用檢索所有城市的列表替換過濾的城市列表（在xhtml表單中，用<f:selectItems value="#{cityBean.citiesByCountry}" />替換<f:selectItems value="#{cityBean.citiesByCountry}" /> <f:selectItems value="#{cityBean.all}" /> ，沒有驗證錯誤，表單已成功提交。

**這是代碼：

形成：

<p:outputLabel for="country" value="#{i18n.country}" />
                    <p:selectOneMenu valueChangeListener="#{cityBean.selectCountry}" rendered="true" id="country" value="#{newMember.country}" converter="#{countryBean.converter}" 
                        style="width:160px;text-align:left;border:thin solid gray;"
                        required="true" requiredMessage="#{i18n.required}">                     
                        <f:selectItems value="#{countryBean.all}" var="countryname" itemLabel="#{countryname.name}"/>
                        <p:ajax event="change" update="city" />
                    </p:selectOneMenu>
                    <p:message for="country" />

                    <p:outputLabel for="city" value="#{i18n.city}" />
                    <p:selectOneMenu rendered="true" id="city" value="#{newMember.city}" converter="#{cityBean.converter}" converterMessage="Conversion error!"
                        style="width:160px;text-align:left;border:thin solid gray;"
                        required="true" requiredMessage="#{i18n.required}">                                         
                        <f:selectItems value="#{cityBean.citiesByCountry}" var="cityname" itemLabel="#{cityname.cityname}"/>                        
                    </p:selectOneMenu>
                    <p:message for="city" />

市實體負責人：

@XmlRootElement
@Entity
@Table(name = "city", schema = "public")
@NamedQueries({
        @NamedQuery(name = "City.findAll", query = "SELECT c FROM City c"),
        @NamedQuery(name = "City.findById", query = "SELECT c FROM City c WHERE c.id = :id"),
        @NamedQuery(name = "City.findByCountry", query = "SELECT c FROM City c WHERE c.country = :country"),
        @NamedQuery(name = "City.findByCountryOrderedByName", query = "SELECT c FROM City c WHERE c.country = :country ORDER BY c.cityname ASC") })
@NamedNativeQueries({ @NamedNativeQuery(name = "City.findCountryNativeSQL", query = "select * from city c where c.countrybeta = :country.betacode", resultClass = City.class) })
public class City implements java.io.Serializable {

    private static final long serialVersionUID = 3364735938266980295L;
    private int id;
    private Integer version;
    private Country country;
    private String cityname;
    private String district;
    private int population;
    private Set<Member> members = new HashSet<Member>(0);

    public City() {
    }
// ...remainder of entity code (contructors and fields..)

豆子：

@Named
@Stateful
@ConversationScoped
public class CityBean implements Serializable {

    private static final long serialVersionUID = 1L;
    private City city;
    private List<City> cityList;

    public City getCity() {
        return this.city;
    }

    private Country selectedCountry;

    @Inject
    private Conversation conversation;

    @PersistenceContext(type = PersistenceContextType.EXTENDED)
    private EntityManager entityManager;
// remainder of code....

// The List that works fine with Select one Menu
public List<City> getAll() {

        CriteriaQuery<City> criteria = this.entityManager.getCriteriaBuilder()
                .createQuery(City.class);
        return this.entityManager.createQuery(
                criteria.select(criteria.from(City.class))).getResultList();
    }

    @PostConstruct
    public void init() {
        setCityList(getCitiesByCountry());
    }

    public List<City> getCityList() {
        return cityList;
    }

    public void setCityList(List<City> cityList) {
        this.cityList = cityList;
    }

    /**
     * The List That triggers a jsf value validation error
     * @return List of Cities by Country ordered by city name
     */
    public List<City> getCitiesByCountry() {
        TypedQuery<City> query = this.entityManager.createNamedQuery(
                "City.findByCountryOrderedByName", City.class);
        query.setParameter("country", selectedCountry);
        return query.getResultList();
    }

    // The Select One Menu Listener
    public void selectCountry(ValueChangeEvent event) {

        if (event != null) {
            selectedCountry = (Country) event.getNewValue();
        }
        }

        // getters and setters....

ENV： - JSF 21 - Hibernate - JBoss AS 7.1 - PrimeFaces 3.5 - Linux 3.5 / Firefox 18.0.2

Answer 1

您的具體問題是由於您沒有在@PostConstruct啟動對話而導致的，因此bean的行為類似於請求作用域。 這樣，在處理表單提交期間城市列表將不兼容地更改並變為空（因此在可用項列表中找不到所選項，因此此驗證錯誤）。

您需要在@PostConstruct啟動對話。

conversation.begin();

也可以看看：

• 如何在JSF 2.0 / 2.1中用CDI替換@ManagedBean / @ViewScope
• 驗證錯誤：值無效

---

與具體問題無關 ，使用valueChangeListener並在getter方法中執行業務邏輯是錯誤的方法。 您根本不應該在getter方法中執行業務邏輯。 這顯然效率低下。 他們應該只返回已經准備好的bean屬性。

重寫您的邏輯如下：

<p:selectOneMenu value="#{bean.country}" ...>
    <f:selectItems value="#{bean.countries}" />
    <p:ajax listener="#{bean.updateCities}" update="city" />
</p:selectOneMenu>

<p:selectOneMenu id="city" value="#{bean.city}" ...>                                         
    <f:selectItems value="#{bean.cities}" />
</p:selectOneMenu>

同

private Country country;
private List<Country> countries;
private City city;
private List<City> cities;

@PostConstruct
public void init() {
    countries = service.listCountries();

public void updateCities() {
    cities = service.listCities(country);
}

// Add/generate normal!! getters/setters.

也可以看看：

• 為什么JSF多次調用getter
• 我們的selectOneMenu標簽維基頁面