Question

我正在使用struts 2和tomcat。我面临的问题是：每当我提交数据是否错误（用户名和密码）时，它都会出现以下字段错误：

.Error setting expression 'userBean.password' with value ['XXX', ]
.Error setting expression 'userBean.username' with value ['YYY', ]

其中'XXX'是密码，'YYY'是用户名。

我的动作类是：

package direstruts.action;

import static com.opensymphony.xwork2.Action.SUCCESS;
import direstruts.model.UserBean;

public class LoginAction extends GenericAction {

    @Override
    public void validate() {
        UserBean uB = getUserBean();
        if(uB.getUsername().isEmpty()) {
            addFieldError("userBean.username", "Por favor Insira o Username de Utilizador");
        }
        if(uB.getPassword().isEmpty()) {
            addFieldError("userBean.password", "Por favor Insira a Password de Utilizador");
        }
    }

    public String getAuthentication() throws Exception {
        if(getUserBean().getAuthentication()) {
            addActionMessage("Log in bem Sucedido!");
            return SUCCESS;
        }
        addActionError("Utilizador e/ou Password errados e/ou Utilizador já está logado");
        return ERROR;
    }

    public String setNewUser() throws Exception {
        if(getUserBean().setNewUser()) {
            addActionMessage("User registado!");
            return SUCCESS;
        }
        addActionError("Utilizador Já Existe! Tente Outro Username!");
        return ERROR;
    }
    public String setQuitUser() throws Exception {
        if(getUserBean().setQuitUser()) {
            addActionMessage("User LoggedOut!");
            return SUCCESS;
        }
        return ERROR;
    }

    public UserBean getUserBean() {
        if(!session.containsKey("userBean"))
            this.setUserBean(new UserBean());
        return (UserBean) session.get("userBean");
    }

    public void setUserBean(UserBean userBean) {
        session.put("userBean", userBean);
    }
}

我的jsp是：

<%@ taglib prefix="s" uri="/struts-tags"%>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%><!DOCTYPE html>
<html>
    <head>

        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <link rel="stylesheet" type="text/css" href="css/styles.css"> 
        <title>MeeTO</title>
    </head>
    <body>

        <s:form action="loginAction" method="post" >
            <s:label cssClass="login" value="Please fill in the form below in order to Register or Log in:" /> <br>

            <s:label for="userBean.username" value="Username:"/> 
            <s:textfield name="userBean.username" /> <br>

            <s:label for="userBean.password"  value="Password:"/> 
            <s:password name="userBean.password" /> <br>

            <s:submit value="LogIn" action="loginAction" /> <br>
            <s:submit value="Register" action="registerAction" /> <br>
        </s:form>

        <s:fielderror/>
        <s:actionerror/>
        <s:actionmessage/>
    </body>
</

我的豆是：

package direstruts.model;

import cliente.replies.ReplyLogin;
import cliente.replies.ReplyObj;
import cliente.requests.lookup.GetAuthentication;
import cliente.requests.modify.SetNewUser;
import cliente.requests.modify.SetQuitUser;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.NotBoundException;
import java.rmi.RemoteException;
import java.util.Properties;
import servidorRMI.ExecuteCommands;

public class UserBean {
    ExecuteCommands eC;
    private static String ip_RMI = "127.0.0.1";
    private static int serverRMI = 1099;
    private static InputStream in;
    private String username;
    private String password;
    private int idUser;

    public UserBean() {
        readProperties();
    }

    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;
    }

    public int getIdUser() {
        return this.idUser;
    }

    public void setIdUser(int idUser) {
        this.idUser = idUser;
    }

    public boolean getAuthentication() {
        GetAuthentication gA = new GetAuthentication(getUsername(), getPassword(), 0);
        ReplyLogin rL = null;
        boolean cond = false;
        do{
            try {
                eC = (ExecuteCommands)Naming.lookup("rmi://" + ip_RMI + ":" + serverRMI + "/ServerRMI");
                rL = eC.getAuthentication(gA);
                cond = false;
            } catch (RemoteException ex) {
                System.err.println("Erro no servidor RMI Remote! A tentar restablecer a ligação!");
                cond = true;
            } catch (NotBoundException ex) {
                System.err.println("Erro no servidor RMI NotBound! A tentar restablecer a ligação!");
                cond = true;
            } catch (MalformedURLException ex) {
                System.err.println("Erro no servidor RMI MalformedURL! A tentar restablecer a ligação!");
                cond = true;
            }
        } while(cond);
        setIdUser(rL.getIdUser()); // Faz set ao idUser para poder ser usado nos pedidos subsequentes
        return rL.isHasRegister();
    }

    public boolean setNewUser() {
        SetNewUser sNU = new SetNewUser(getUsername(), getPassword(), 0);
        boolean cond = false;
        ReplyObj rO = null;
        do{
            try {
                eC = (ExecuteCommands)Naming.lookup("rmi://" + ip_RMI + ":" + serverRMI + "/ServerRMI");
                rO = eC.setNewUser(sNU);
                cond = false;
            } catch (RemoteException ex) {
                System.err.println("Erro no servidor RMI Remote! A tentar restablecer a ligação!");
                cond = true;
            } catch (NotBoundException ex) {
                System.err.println("Erro no servidor RMI NotBound! A tentar restablecer a ligação!");
                cond = true;
            } catch (MalformedURLException ex) {
                System.err.println("Erro no servidor RMI MalformedURL! A tentar restablecer a ligação!");
                cond = true;
            }
        } while(cond);
        return rO.getSuccess();
    }

    public boolean setQuitUser() {
        SetQuitUser sQU = new SetQuitUser(idUser, 0);
        boolean cond = false;
        ReplyObj rO = null;
        do{
            try {
                eC = (ExecuteCommands)Naming.lookup("rmi://" + ip_RMI + ":" + serverRMI + "/ServerRMI");
                rO = eC.setQuitUser(sQU);
                cond = false;
            } catch (RemoteException ex) {
                System.err.println("Erro no servidor RMI Remote! A tentar restablecer a ligação!");
                cond = true;
            } catch (NotBoundException ex) {
                System.err.println("Erro no servidor RMI NotBound! A tentar restablecer a ligação!");
                cond = true;
            } catch (MalformedURLException ex) {
                System.err.println("Erro no servidor RMI MalformedURL! A tentar restablecer a ligação!");
                cond = true;
            }
        } while(cond);
        return rO.getSuccess();
    }

    static public void readProperties() {
        try {
            Properties properties = new Properties();
            in = UserBean.class.getClassLoader().getResourceAsStream("app.properties");
            properties.load(in);
            ip_RMI = properties.getProperty("serverRMI.address");
            serverRMI = Integer.parseInt (properties.getProperty("serverRMI.port"));
        } catch(IOException e) {
            System.err.println("Erro a ler o ficheiro .properties!");
        } finally {
            if(in != null) {
                try {
                    in.close();
                } catch(IOException e) {System.out.println("Erro a fechar!"); }
            }
        }
    }
}

这是Tomcat Log：

19-Nov-2014 14:21:04.618 WARNING [http-apr-8080-exec-109] com.opensymphony.xwork2.util.logging.jdk.JdkLogger.warn Parameter [action:loginAction] is on the excludeParams list of patterns!
19-Nov-2014 14:21:05.086 SEVERE [http-apr-8080-exec-109] null.null Notificação para o Desenvolvedor (altere o paramêtro struts.devMode para false para desabilitar esta mensagem):
Unexpected Exception caught setting 'userBean.password' on 'class direstruts.action.LoginAction: Error setting expression 'userBean.password' with value ['YYY', ]
19-Nov-2014 14:21:05.101 SEVERE [http-apr-8080-exec-109] null.null Notificação para o Desenvolvedor (altere o paramêtro struts.devMode para false para desabilitar esta mensagem):
Unexpected Exception caught setting 'userBean.username' on 'class direstruts.action.LoginAction: Error setting expression 'userBean.username' with value ['XXX', ]
19-Nov-2014 14:21:05.210 WARNING [http-apr-8080-exec-109] com.opensymphony.xwork2.util.logging.jdk.JdkLogger.warn Caught an exception while evaluating expression 'userBean.username' against value stack
 Caught an Ognl exception while getting property userBean - Class: ognl.OgnlRuntime
File: OgnlRuntime.java
Method: getMethodValue
Line: 1456 - ognl/OgnlRuntime.java:1456:-1
    at com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:143)
    at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:2317)
    at ognl.ASTProperty.getValueBody(ASTProperty.java:114)
    at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
    at ognl.SimpleNode.getValue(SimpleNode.java:258)
    at ognl.ASTChain.getValueBody(ASTChain.java:141)
    at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
    at ognl.SimpleNode.getValue(SimpleNode.java:258)
    at ognl.Ognl.getValue(Ognl.java:494)
    at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:255)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.getValue(OgnlValueStack.java:358)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValue(OgnlValueStack.java:347)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValueWhenExpressionIsNotNull(OgnlValueStack.java:322)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:308)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:366)
    at com.opensymphony.xwork2.util.TextParseUtil$1.evaluate(TextParseUtil.java:157)
    at com.opensymphony.xwork2.util.OgnlTextParser.evaluate(OgnlTextParser.java:49)
    at com.opensymphony.xwork2.util.TextParseUtil.translateVariables(TextParseUtil.java:167)
    at com.opensymphony.xwork2.util.TextParseUtil.translateVariables(TextParseUtil.java:112)
    at com.opensymphony.xwork2.util.TextParseUtil.translateVariables(TextParseUtil.java:85)
    at org.apache.struts2.components.Component.findValue(Component.java:353)
    at org.apache.struts2.components.UIBean.evaluateParams(UIBean.java:813)
    at org.apache.struts2.components.UIBean.end(UIBean.java:544)
    at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:42)
    at org.apache.jsp.loginPage_jsp._jspx_meth_s_005ftextfield_005f0(loginPage_jsp.java:273)
    at org.apache.jsp.loginPage_jsp._jspx_meth_s_005fform_005f0(loginPage_jsp.java:182)
    at org.apache.jsp.loginPage_jsp._jspService(loginPage_jsp.java:114)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:164)
    at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
    at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:371)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:275)
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:562)
    at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
    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:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2403)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2392)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: ognl.OgnlException: userBean [java.lang.NullPointerException]
    at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:1456)
    at ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:60)
    at ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:147)
    at com.opensymphony.xwork2.ognl.accessor.ObjectAccessor.getProperty(ObjectAccessor.java:17)
    at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:2317)
    at com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:138)
    ... 68 more
Caused by: java.lang.NullPointerException
    at java.util.Properties$LineReader.readLine(Properties.java:434)
    at java.util.Properties.load0(Properties.java:353)
    at java.util.Properties.load(Properties.java:341)
    at direstruts.model.UserBean.readProperties(UserBean.java:128)
    at direstruts.model.UserBean.<init>(UserBean.java:27)
    at direstruts.action.LoginAction.getUserBean(LoginAction.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:891)
    at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:1454)
    ... 73 more

19-Nov-2014 14:21:05.288 WARNING [http-apr-8080-exec-109] com.opensymphony.xwork2.util.logging.jdk.JdkLogger.warn NOTE: Previous warning message was issued due to devMode set to true.
19-Nov-2014 14:21:05.429 WARNING [http-apr-8080-exec-109] com.opensymphony.xwork2.util.logging.jdk.JdkLogger.warn Caught an exception while evaluating expression 'userBean.password' against value stack
 Caught an Ognl exception while getting property userBean - Class: ognl.OgnlRuntime
File: OgnlRuntime.java
Method: getMethodValue
Line: 1456 - ognl/OgnlRuntime.java:1456:-1
    at com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:143)
    at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:2317)
    at ognl.ASTProperty.getValueBody(ASTProperty.java:114)
    at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
    at ognl.SimpleNode.getValue(SimpleNode.java:258)
    at ognl.ASTChain.getValueBody(ASTChain.java:141)
    at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
    at ognl.SimpleNode.getValue(SimpleNode.java:258)
    at ognl.Ognl.getValue(Ognl.java:494)
    at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:255)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.getValue(OgnlValueStack.java:358)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValue(OgnlValueStack.java:347)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValueWhenExpressionIsNotNull(OgnlValueStack.java:322)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:308)
    at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:366)
    at com.opensymphony.xwork2.util.TextParseUtil$1.evaluate(TextParseUtil.java:157)
    at com.opensymphony.xwork2.util.OgnlTextParser.evaluate(OgnlTextParser.java:49)
    at com.opensymphony.xwork2.util.TextParseUtil.translateVariables(TextParseUtil.java:167)
    at com.opensymphony.xwork2.util.TextParseUtil.translateVariables(TextParseUtil.java:112)
    at com.opensymphony.xwork2.util.TextParseUtil.translateVariables(TextParseUtil.java:85)
    at org.apache.struts2.components.Component.findValue(Component.java:353)
    at org.apache.struts2.components.UIBean.evaluateParams(UIBean.java:813)
    at org.apache.struts2.components.UIBean.end(UIBean.java:544)
    at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:42)
    at org.apache.jsp.loginPage_jsp._jspx_meth_s_005fpassword_005f0(loginPage_jsp.java:313)
    at org.apache.jsp.loginPage_jsp._jspx_meth_s_005fform_005f0(loginPage_jsp.java:191)
    at org.apache.jsp.loginPage_jsp._jspService(loginPage_jsp.java:114)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:164)
    at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
    at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:371)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:275)
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:562)
    at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
    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:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2403)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2392)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: ognl.OgnlException: userBean [java.lang.NullPointerException]
    at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:1456)
    at ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:60)
    at ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:147)
    at com.opensymphony.xwork2.ognl.accessor.ObjectAccessor.getProperty(ObjectAccessor.java:17)
    at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:2317)
    at com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:138)
    ... 68 more
Caused by: java.lang.NullPointerException
    at java.util.Properties$LineReader.readLine(Properties.java:434)
    at java.util.Properties.load0(Properties.java:353)
    at java.util.Properties.load(Properties.java:341)
    at direstruts.model.UserBean.readProperties(UserBean.java:128)
    at direstruts.model.UserBean.<init>(UserBean.java:27)
    at direstruts.action.LoginAction.getUserBean(LoginAction.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:891)
    at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:1454)
    ... 73 more

19-Nov-2014 14:21:05.507 WARNING [http-apr-8080-exec-109] com.opensymphony.xwork2.util.logging.jdk.JdkLogger.warn NOTE: Previous warning message was issued due to devMode set to true.

[编辑] 我忘了提到我有一个行动，其他所有行动都延伸。这是：

package direstruts.action;

import com.opensymphony.xwork2.ActionSupport;
import java.util.Map;
import org.apache.struts2.interceptor.SessionAware;

public class GenericAction extends ActionSupport implements SessionAware{
    protected static final long serialVersionUID = 4L;
    protected Map<String, Object> session;

    @Override
    public void setSession(Map<String, Object> session) {
        this.session = session;
    } 
}

为了保留动作内存，GenericAction实现了SessionAware。那可以吗？

Answer 1

如Parameters Interceptor documentation（以及explained in this answer）中所述，例外情况：

.Error设置表达式＆＃39; userBean.password＆＃39;有价值[＆＃39; XXX＆＃39;，]

意味着你错过了Setter。

JavaBeans约定确定你应该有一个属性，带有一个具有相同名称的getter和setter，Struts2遵循这些原则，通过反射执行内省以概述你的Action对象。

您的代码中有什么内容？

public UserBean getUserBean() {
    if(!session.containsKey("userBean"))
        this.setUserBean(new UserBean());
    return (UserBean) session.get("userBean");
}

public void setUserBean(UserBean userBean) {
    session.put("userBean", userBean);
}

有点不合标准，呃！

属性private UserBean userBean;甚至不存在，getter和setter正在做奇怪的会话事情（虽然他们甚至不应该有任何业务）。

将其更改为

private UserBean userBean;

public UserBean getUserBean() {
    return userBean; 
}

public void setUserBean(UserBean userBean) {
    this.userBean = userBean; 
}

它会起作用。

然后如果需要，找到另一种处理会话和对象的方法（例如prepare()方法，甚至是execute()）。

设置表达式时出错＆＃39; userBean.password＆＃39;有价值的[＆＃39;＆＃39;，]

1 个答案: