目标不可达，标识符解析为空，已定义 Bean [重复]

【问题标题】：Target Unreachable, identifier resolved to null with defined Bean [duplicate]目标不可达，标识符解析为空，已定义 Bean [重复]
【发布时间】：2014-08-29 16:07:16
【问题描述】：

最近，我遇到了奇怪的错误，这意味着一件事，但我正在经历另一件事。通常，当发生此错误时，这意味着我的 Bean 没有正确命名，因此我试图访问一个不存在的 Bean。可以在此处找到示例：JSF Target unreachable identifier resolved to null。

在这种情况下，我使用的是 CDI：

打包帐号；

import general.Env;

import java.io.PrintWriter;
import java.io.Serializable;
import java.io.StringWriter;

import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;

import org.apache.directory.ldap.client.api.LdapConnection;
import org.apache.directory.ldap.client.api.LdapNetworkConnection;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

@ManagedBean(name="account")
@SessionScoped
public class Account implements Serializable{

String username;
String password;
String ouName;
String error = "";
Logger log = LogManager.getLogger("QCAuth");

public String getOuName() {
    return ouName;
}
public void setOuName(String ouName) {
    this.ouName = ouName;
}
public String getError() {
    return error;
}
public void setError(String error) {
    this.error = error;
}
public String getUsername() {
    return username;
}
public void setUsername(String username) {
    this.username = username;
}
public String getPassword() {
    return password;
}
public void setPassword(String password) {
    this.password = password;
}

我的 html 抛出错误：

        <h:form id="form" method="post" onsubmit="return fullCheck()">

            <div id="userdiv" class="form-inline">
                <label for="username" class="control-label" style="color: #2E8AE6;margin-right:  
50px">Username: </label>
                <h:inputText class="form-control" id="user" style="margin-right: 125px" value="#
{account.username}"/>
            </div>

            <div class="form-inline">   
            &nbsp;
            </div>
            <div id="passdiv"  class="form-inline">
                <label for="password" class="control-label" style="color: #2E8AE6;margin-right: 
50px">Password: </label>
                <h:inputText class="form-control" id="pass" style="margin-right: 123px" value="#
{account.password}"/>
            </div>
            &nbsp;
            <div  class="form-inline">
                <h:commandButton styleClass="btn btn-primary" style="background-image:linear-
gradient(to bottom, #2E8AE6 0%,  #174470 100%);
                color:#000000" id="submit" value="Submit" action="#{account.login}"/>
            </div>  
        </h:form>

堆栈跟踪：

WARNING: /index.xhtml @75,107 value="#{account.username}": Target Unreachable, identifier   
'account' resolved to null
javax.el.PropertyNotFoundException: /index.xhtml @75,107 value="#{account.username}": Target   
Unreachable, identifier 'account' resolved to null
at com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:100)
at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue
(HtmlBasicInputRenderer.java:95)
at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1046)
at javax.faces.component.UIInput.validate(UIInput.java:976)
at javax.faces.component.UIInput.executeValidate(UIInput.java:1249)
at javax.faces.component.UIInput.processValidators(UIInput.java:712)
at javax.faces.component.UIForm.processValidators(UIForm.java:253)
at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1261)
at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1195)
at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:67)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process
(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:722)
Caused by: javax.el.PropertyNotFoundException: Target Unreachable, identifier 'account' resolved    
to null
at org.apache.el.parser.AstValue.getTarget(AstValue.java:97)
at org.apache.el.parser.AstValue.getType(AstValue.java:81)
at org.apache.el.ValueExpressionImpl.getType(ValueExpressionImpl.java:171)
at com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:98)

我的 WEB-INF 文件夹中有 beans.xml（它是空的）。当尝试填写 jsf 组件的值或操作时，Eclipse 提供“帐户”作为可能的 Bean，并且我能够通过默认提议拉取 Bean 的 getter、setter 和方法。本质上，Eclipse 告诉我 bean 已正确定义。此错误的任何可能原因？

编辑：无论出于何种原因，在表单提交之前检查我的网页时，我的 javascript 也有错误。我仔细检查过，一切看起来都很好。不确定这是否有帮助

编辑 2：事实证明我所有的标识符都显示为空。刚刚尝试了我的 env bean 并得到了以下堆栈跟踪：

javax.servlet.ServletException: javax.el.PropertyNotFoundException: /index.xhtml @102,259  
action="#{env.devMode}": Target Unreachable, identifier 'env' resolved to null
javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:67)

root cause

javax.faces.el.EvaluationException: javax.el.PropertyNotFoundException: /index.xhtml @102,259    
action="#{env.devMode}": Target Unreachable, identifier 'env' resolved to null
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAd
apter.java:94)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:67)
root cause

javax.el.PropertyNotFoundException: /index.xhtml @102,259 action="#{env.devMode}": Target    
Unreachable, identifier 'env' resolved to null
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:107)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAd    apter.java:87)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:67)

类：

package general;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Properties;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.inject.Named;

@ManagedBean(name="env")
@ViewScoped
public class Env {

public static boolean prod = true;
public static String[] ouValues;
static int i = 0;

public static void initialize() 
{
    getConfigProperties config = new getConfigProperties();
    Properties prop = config.getConfig();

    String temp = prop.getProperty("ouValues");
    ArrayList<String> tempProdArr= new ArrayList<String>(Arrays.asList(temp.split("\\s*,\\s*")));
    ouValues=tempProdArr.toArray(new String[tempProdArr.size()]);
}

public static String[] getOuValues() {
    return ouValues;
}

public static void setOuValues(String[] ouValues) {
    Env.ouValues = ouValues;
}

public static boolean isProd()
{
    if (i == 0) {
        initialize();
        i = 1;
    }

    return prod;
}

public String devMode() {
    prod = false;
    return "index.xhtml";
}   

public void prodMode() {
    prod = true;
}
}

所以基本上，我有多个 bean，当它们实际上被正确定义时，它们被混淆为空标识符。我安装的 Eclipse 会导致这种情况吗？或者可能是与 tomcat 相关的问题，例如未正确加载我的托管 bean？我真的不知道从这里去哪里。

【问题讨论】：

  • 像往常一样，SessionScoped 来自哪个包？而fullCheck()是什么，它似乎是一种非标准的验证方式？
  • 请包含完整的堆栈跟踪和您的导入语句。
  • @JaqenH'ghar fullcheck() 只是一个包含在 javascript 文件中的验证方法。包是 javax.faces.bean。
  • 我已经为这个问题苦苦挣扎了两天了。这没有道理。似乎可行的是剥离所有内容的类和 xhtml 页面，然后逐行缓慢地添加所有内容。

标签： jsf-2 cdi


【解决方案1】：

未能定义类 org.apache.directory.ldap.client.api.LdapConnection 导致我的 Account 类无法加载。结果，Tomcat 无法找到该类。在我的 WEB-INF/lib 文件夹中包含这个 jar 之后，这些错误就消失了。

【讨论】：

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