Question

我正在尝试基于提交表单启用和禁用按钮的简单示例。如果有人也可以指出jsf：id的概念，因为我将普通的html5与jsf混合。

以下是相关代码：

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
     xmlns:jsf="http://java.sun.com/jsf" 
     xmlns:f="http://java.sun.com/jsf/core">
    <head jsf:id="head">
        <title>Putting it all together </title>
        <!-- script jsf:target="body" jsf:name="js.js"/>
        <link jsf:name="css.css" rel="stylesheet" type="text/css" /-->
    </head>
    <body jsf:id="body">
        <form jsf:id="form" jsf:prependId="false">
            <label jsf:for="name">Name </label>
            <input jsf:id="name" type="text" jsf:value="#{complex.name}">
                <f:ajax execute="@this" render="progress"/>
            </input>
            <label jsf:for="tel">Tel </label>
            <input jsf:id="tel" type="tel" jsf:value="#{complex.tel}">
                <f:ajax execute="@this" render="progress"/>
            </input>

            <label jsf:for="email">Email </label>
            <input jsf:id="email" type="email" jsf:value="#{complex.email}">
                <f:ajax execute="@this" render="progress"/>
            </input>

            <label for="progress">Progress </label>
            <progress jsf:id="progress" max="3">#{complex.progress} of 3 </progress>


            <input jsf:id="submit" type="submit" value="submit">
                <f:ajax execute="@this" render="login" event="click" listener="#{complex.process}" />
            </input>

            <!-- label jsf:id="status"></label-->
            <button jsf:id="login" disabled="#{complex.status}">Login</button>

        </form>
    </body>
</html>

托管bean是：

package mypackage.bean;
import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.event.AjaxBehaviorEvent;

@ManagedBean
@SessionScoped
public class Complex implements Serializable {
    public Complex() {}

    private String name;
    private String tel;
    private String email;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getTel() {
        return tel;
    }
    public void setTel(String tel) {
        this.tel = tel;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    private boolean status;

    public void process(AjaxBehaviorEvent event) {
        status = !status;
    }


    public boolean isStatus() {
        return status;
    }

    public boolean getStatus() {
        return status;
    }

    public void setStatus(boolean status) {
        this.status = status;
    }

    public String getProgress() {
        int progress = 0;
        if(name != null) {
            progress++;
        }
        if(tel != null) {
            progress++;
        }
        if(email != null) {
            progress++;
        }
        return progress + "";
    }


}

这是错误打印到网页：

HTTP Status 500 - java.lang.Boolean cannot be cast to java.lang.String

type Exception report

message java.lang.Boolean cannot be cast to java.lang.String

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: java.lang.Boolean cannot be cast to java.lang.String
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)

root cause

java.lang.ClassCastException: java.lang.Boolean cannot be cast to java.lang.String
    com.sun.faces.renderkit.html_basic.HtmlResponseWriter.getAttributeValue(HtmlResponseWriter.java:1210)
    com.sun.faces.renderkit.html_basic.HtmlResponseWriter.flushAttributes(HtmlResponseWriter.java:1170)
    com.sun.faces.renderkit.html_basic.HtmlResponseWriter.closeStartIfNecessary(HtmlResponseWriter.java:1112)
    com.sun.faces.renderkit.html_basic.HtmlResponseWriter.writeText(HtmlResponseWriter.java:935)
    com.sun.faces.facelets.compiler.LiteralTextInstruction.write(LiteralTextInstruction.java:76)
    com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:82)
    com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:183)
    javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
    javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:900)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1847)
    javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
    javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:900)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1847)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1850)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1850)
    com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:443)
    com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
    com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
    com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:202)
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)

note The full stack trace of the root cause is available in the Apache Tomcat/7.0.35 logs.
Apache Tomcat/7.0.35

Answer 1

代码的关键部分是

<button jsf:id="login" disabled="#{complex.status}">Login</button>

然后这个例外

java.lang.ClassCastException: java.lang.Boolean cannot be cast to java.lang.String

现在它代表<button>代码，disabled属性的值不是boolean而是String。
因此，此属性的值为{ {1}}。
请see this question as well处理HTML5的disabled="disabled"属性您需要从托管bean设置String值，并将disabled属性声明为status而不是String。

在jsf 2.2中启用禁用按钮

1 个答案: