javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": class 'java.lang.String' 没有属性 'name'

Question

如果我第一次加上stackElement就可以了，输出是：

list size = 1

但是在添加第二个元素后出现错误：

Error Rendering View[/tab.xhtml]: javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": The class 'java.lang.String' does not have the property 'name'. ... Caused by: javax.el.PropertyNotFoundException: The class 'java.lang.String' does not have the property 'name'.

ERROR [io.undertow.request] (default task-4) UT005023: Exception handling request to /Play/tab.xhtml: java.lang.IllegalStateException: CDATA tags may not nest ...

为什么会这样？

页

<h:form>

    <p:commandButton update="stack" value="Use in expression" action="#{bean.tab}">
        <f:param name="i" value="13" />
    </p:commandButton>

    <p:orderList  id="stack" value="#{expression.list}" var="stackElement" 
            itemLabel="#{stackElement}" itemValue="#{stackElement}" controlsLocation="none" >
        <!-- <p:ajax event="reorder" listener="#{expression.onReorder}" /> -->
        <p:column>
            <h:outputText value="#{stackElement.name}" />
        </p:column>
    </p:orderList>

</h:form>

豆子

@ManagedBean @RequestScoped 
public class Bean implements Serializable {
    @ManagedProperty(value="#{expression}")
    private Expression ex;
    public void tab() { 
        ex.addStackElement( new StackElement((int) System.currentTimeMillis(), "tab") );
    }
    // getters-setters

豆子

@ManagedBean @SessionScoped
public class Expression implements Serializable {
    private List<StackElement> list = new ArrayList<StackElement>();
    public void addStackElement(StackElement stackElement) {
        list.add(stackElement);
        System.out.println("list size = " + list.size()); 
    }
    // getters-setters

型号

public class StackElement {
    private int id;
    private String name;
    public StackElement(int id, String name) {
        this.id = id;
        this.name = name;
    }
    // getters-setters

转换器

@FacesConverter("myConverter")
public class MyConverter implements Converter {

    @Override
    public Object getAsObject(FacesContext fc, UIComponent component, String value) {
        if(value != null && value.trim().length() > 0) {
            try {
                Expression service = (Expression) fc.getExternalContext().getApplicationMap().get("expression");
                return service.getStackElementByName(value);
            } catch(NumberFormatException e) {
                throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Conversion Error", "Not a valid element name."));
            }
        }
        else {
            return null;
        }
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object object) {

        if(object != null) {
            return String.valueOf(((StackElement) object).getName());
        }
        else {
            return null;
        }
    }
}

Answer 1

您的代码几乎没有问题。

您应该在 <p:orderList> 组件上使用 converter="myConverter"。
表达式bean 属于SessionScoped。但是您是从 ApplicationScope 获取它的。

改为

表达式服务=（表达式）fc.getExternalContext().getSessionMap().get("expression");

进行这些更改后它的工作。

javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": class 'java.lang.String' 没有属性 'name'

javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": The class 'java.lang.String' does not have the property 'name'

jsf

primefaces

propertynotfoundexception

javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": class 'java.lang.String' 没有 属性 'name'

javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": The class 'java.lang.String' does not have the property 'name'

jsf

primefaces

propertynotfoundexception

javax.el.PropertyNotFoundException: /tab.xhtml @65,50 value="#{stackElement.name}": class 'java.lang.String' 没有属性 'name'