java.lang.NoClassDefFoundError:无法初始化类financeiro.util.JpaUtil

Question

我需要帮助来显示电子书Algaworks的咨询结果页面。欢迎任何帮助！

控制台（日志文件）

 jul 25, 2016 10:42:45 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
ADVERTÊNCIA: #{consultaLancamentosBean.consultar}: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
javax.faces.FacesException: #{consultaLancamentosBean.consultar}: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
    at javax.faces.component.UIViewAction.broadcast(UIViewAction.java:559)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    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:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)
Caused by: javax.faces.el.EvaluationException: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:94)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    ... 28 more
Caused by: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:107)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
    ... 29 more
jul 25, 2016 10:42:45 PM com.sun.faces.context.ExceptionHandlerImpl log
1100: JSF1073: javax.faces.FacesException obtido durante o processamento de INVOKE_APPLICATION 5: UIComponent-ClientId=, Message=#{consultaLancamentosBean.consultar}: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
jul 25, 2016 10:42:45 PM com.sun.faces.context.ExceptionHandlerImpl log
1100: #{consultaLancamentosBean.consultar}: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
javax.faces.FacesException: #{consultaLancamentosBean.consultar}: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:89)
    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:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)
Caused by: javax.faces.FacesException: #{consultaLancamentosBean.consultar}: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
    at javax.faces.component.UIViewAction.broadcast(UIViewAction.java:559)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    ... 24 more
Caused by: javax.faces.el.EvaluationException: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:94)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    ... 28 more
Caused by: javax.el.PropertyNotFoundException: /ConsultaLancamentos.xhtml @10,65 action="#{consultaLancamentosBean.consultar}": Target Unreachable, identifier 'consultaLancamentosBean' resolved to null
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:107)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
    ... 29 more

--->Persistence.xml（/src/main/resources/META-INF）:

<?xml version="1.0" encoding="UTF-8" ?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
    version="2.1">
    <persistence-unit name="FinanceiroPU">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <class>com.janaina.financeiro.model.Pessoa</class>
        <class>com.janaina.financeiro.model.Lancamento</class>
        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/financeiro" />
            <property name="javax.persistence.jdbc.user" value="postgres" />
            <property name="javax.persistence.jdbc.password" value="postgres" />
            <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="hibernate.hbm2ddl.auto" value="update" />
        </properties>
    </persistence-unit>
</persistence>

--->ConsultaLacamentos.xhtml:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://xmlns.jcp.org/jsf/core"
    xmlns:h="http://xmlns.jcp.org/jsf/html">
<h:head>
    <title>Consulta de lançamentos</title>
</h:head>
<h:body>
    <f:metadata>
        <f:viewAction action="#{consultaLancamentosBean.consultar}" />
    </f:metadata>
    <h1>Consulta de lançamentos</h1>
    <h:form id="frm">
        <h:dataTable value="#{consultaLancamentosBean.lancamentos}"
            var="lancamento" border="1" cellspacing="0" cellpadding="2">
            <h:column>
                <f:facet name="header">
                    <h:outputText value="Pessoa" />
                </f:facet>
                <h:outputText value="#{lancamento.pessoa.nome}" />
            </h:column>
            <h:column>
                <f:facet name="header">
                    <h:outputText value="Descrição" />
                </f:facet>
                <h:outputText value="#{lancamento.descricao}" />
            </h:column>
            <h:column>
                <f:facet name="header">
                    <h:outputText value="Tipo" />
                </f:facet>
                <h:outputText value="#{lancamento.tipo}" />
            </h:column>
            <h:column>
                <f:facet name="header">
                    <h:outputText value="Valor" />
                </f:facet>
                <h:outputText value="#{lancamento.valor}" />
            </h:column>
            <h:column>
                <f:facet name="header">
                    <h:outputText value="Data de vencimento" />
                </f:facet>
                <h:outputText value="#{lancamento.dataVencimento}" />
            </h:column>
            <h:column>
                <f:facet name="header">
                    <h:outputText value="Data de pagamento" />
                </f:facet>
                <h:outputText value="#{lancamento.dataPagamento}" />
            </h:column>
        </h:dataTable>
    </h:form>
</h:body>
</html>

--->咨询LacamentosBean.java

package com.janaina.financeiro.controller;
import java.io.Serializable;
import java.util.List;
import javax.faces.bean.ManagedBean;
import javax.faces.view.ViewScoped;
import javax.persistence.EntityManager;
import javax.persistence.TypedQuery;
import com.janaina.financeiro.model.Lancamento;
import com.janaina.financeiro.util.JpaUtil;
@ManagedBean
@ViewScoped
public class ConsultaLancamentosBean implements Serializable {
    private static final long serialVersionUID = 1L;
    private List<Lancamento> lancamentos;
    public void consultar() {
        EntityManager manager = JpaUtil.getEntityManager();
        TypedQuery<Lancamento> query = manager.createQuery("from Lancamento", Lancamento.class);
        this.lancamentos = query.getResultList();
        manager.close();
    }
    public List<Lancamento> getLancamentos() {
        return lancamentos;
    }
}

--->JpaUtil.java

package com.janaina.financeiro.util;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
//JpaUtil armazena a instância compartilhada de EntityManagerFactory em uma variável estática
//Qualquer código terá acesso fácil e rápido
//Sempre que for preciso uma EntityManager basta chamar:
//EntityManager manager = JpaUtil.getEntityManager();
public class JpaUtil {
    private static EntityManagerFactory factory;
    static {
        factory = Persistence.createEntityManagerFactory("FinanceiroPU");
    }
    public static EntityManager getEntityManager() {
        return factory.createEntityManager();
    }
}

Answer 1

我解决了这个问题！我意识到我的问题的原因是：

1） 我在项目中使用的是Java JRE，而不是JDK。为了解决这个问题，我做了以下操作：右键单击项目>属性>Java构建路径>库>我正在使用的选定JRE>编辑>已安装的JRE>搜索>JDK路径（C:\Program Files\Java\jdk1.8.0_101）。

2） 然后我意识到我无法连接到PostgreSQL。然后我卸载了PostgreSQL，也删除了它在程序文件中的目录，然后我重新安装了！

3） 最后：Rigth点击Project>Run as>Maven>Maven Clean，然后Rigth点击项目>Run as>Maven>安装

上面的步骤对我很有效。我希望它们能帮助其他人！

我的（web.xml）:

<context-param>
                <param-name>javax.faces.PROJECT_STAGE</param-name>
                <param-value>Development</param-value>
        </context-param>
        <servlet>
                <servlet-name>Faces Servlet</servlet-name>
                <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
                <load-on-startup>1</load-on-startup>
        </servlet>
        <servlet-mapping>
                <servlet-name>Faces Servlet</servlet-name>
                <url-pattern>/faces/*</url-pattern>
        </servlet-mapping>

persistence.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
        version="2.1">
        <persistence-unit name="FinanceiroPU">
                <provider>org.hibernate.ejb.HibernatePersistence</provider>
                <class>com.janaina.financeiro.model.Lancamento</class>
                <class>com.janaina.financeiro.model.Pessoa</class>
                <properties>
                        <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/financeiro" />
                        <property name="javax.persistence.jdbc.user" value="postgres" />
                        <property name="javax.persistence.jdbc.password" value="postgres" />
                        <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
                        <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
                        <property name="hibernate.show_sql" value="true" />
                        <property name="hibernate.format_sql" value="true" />
                        <property name="hibernate.hbm2ddl.auto" value="update" />
                </properties>
        </persistence-unit>
</persistence>