为什么f:validateDoubleRange仅适用于@SessionScoped？

Question

有人可以向我解释为什么我的例子中的Foo在到达validateDoubleRange类时总是为空？最终结果是验证器的最小值始终为0.在outputText元素中,数字3在页面上显示正常.如果我做豆@SessionScoped而不是它,它验证很好@ViewScoped

控制器:

import java.io.Serializable;
import java.math.BigDecimal;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;

@ViewScoped
@ManagedBean(name = "fooController")
public class FooController implements Serializable {

    private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(FooController.class);
    private static final long serialVersionUID = 1L;
    private Foo foo;
    private BigDecimal amount;
    private Long fooId;

    public Long getFooId() {
        return fooId;
    }

    public void setFooId(Long fooId) {
        this.fooId = fooId;
        this.foo = new Foo();
        foo.setFooId(fooId);
        foo.setMinAmount(Double.valueOf(3));
        foo.setMaxAmount(Double.valueOf(10));
    }

    public Foo getFoo() {
        return foo;
    }

    public void sendAmount() {
        log.debug("sendAmount: " + amount);
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public void setAmount(BigDecimal amount) {
        this.amount = amount;
    }

    public static class Foo {

        private Long fooId;
        private Double minAmount;
        private Double maxAmount;

        public Foo() {
        }

        public void setFooId(Long fooId) {
            this.fooId = fooId;
        }

        public void setMinAmount(Double minAmount) {
            this.minAmount = minAmount;
        }

        public void setMaxAmount(Double maxAmount) {
            this.maxAmount = maxAmount;
        }

        public Long getFooId() {
            return fooId;
        }

        public Double getMaxAmount() {
            return maxAmount;
        }

        public Double getMinAmount() {
            return minAmount;
        }
    }
}

JSP:

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
            xmlns:ui="http://java.sun.com/jsf/facelets"
            xmlns:f="http://java.sun.com/jsf/core"
            xmlns:h="http://java.sun.com/jsf/html"
            >
<f:metadata>
    <f:viewParam name="fooId" value="#{fooController.fooId}" />        
</f:metadata>
<h:form id="myForm">
    <h:outputText value="This is correctly displayed: '#{fooController.foo.minAmount}'"/><br/>
    <h:outputText value="My Input:" />
    <h:inputText id="myInput"
                 value="#{fooController.amount}" 
                 required="true"
                 >
        <f:convertNumber maxFractionDigits="2"/>
        <f:validateDoubleRange minimum="#{fooController.foo.minAmount}" maximum="80"/>
    </h:inputText>
    <h:message for="myInput"/>
    <br/>
    <h:commandButton id="myButton"
                     value="Save Amount"
                     action="#{fooController.sendAmount}"
                     >
    </h:commandButton>
</h:form>
</ui:composition>

我在JBoss 6.1上使用JSF 2

如果你在那里@BalusC,这是我能想到的最简单的例子,和昨天一样,我希望,澄清并且更容易复制.

- 编辑,我应该补充说fooId是通过视图参数设置的,所以你需要在URL的末尾使用？fooId = 3.

Answer 1

我现在明白为什么我昨天无法重现这一点.在我的游乐场环境中,我意外地将以下上下文参数设置为与默认值不同:

<context-param>
    <param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
    <param-value>false</param-value>
</context-param>

此问题与JSF 问题1492有关.一<f:validateDoubleRange>,其属性是由EL绑定到视图作用域的bean属性将隐含的全豆重建因讨厌的鸡-蛋的问题,因为验证是在每个请求的基础上创建和这些属性都在验证的建设要传递.

如果您不想禁用部分状态保存(非常合理),那么最好的办法是自己在视图作用域托管bean中创建并保存验证器:

public Validator getValidator() {
    return new DoubleRangeValidator(foo.getMaximum(), foo.getMinimum());
}

(注意,在getter中执行这些操作是一个糟糕的设计,但是因为你正在准备foo一个setter而不是一个preRenderView监听器方法,所以没有其他方法,否则它将在同一个监听器方法中完成)

同

<h:inputText validator="#{fooController.validator.validate}" ...>

或者,替代地,为替换以下内容的那个创建自定义验证器<f:validateDoubleRange>:

<f:validator validatorId="bindableDoubleRangeValidator" />
<f:attribute name="minimum" value="#{fooController.foo.minAmount}" />
<f:attribute name="maximum" value="#{fooController.foo.maxAmount}" />

同

package com.example;

import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.DoubleRangeValidator;
import javax.faces.validator.FacesValidator;
import javax.faces.validator.ValidatorException;

@FacesValidator("bindableDoubleRangeValidator")
public class BindableDoubleRangeValidator extends DoubleRangeValidator {

    @Override
    public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
        setMinimum((Double) component.getAttributes().get("minimum"));
        setMaximum((Double) component.getAttributes().get("maximum"));
        super.validate(context, component, value);
    }

}

更新:鸡蛋问题1492自Mojarra 2.1.18(2013年1月)起修复.所以,如果你这些天偶然发现,那么你也可以考虑升级.