JSF2在后退按钮上显示旧值

Question

我在PRG Pattern上做了几次测试。我还阅读了本网站关于后退按钮问题的许多答案。 我坚持认为代码是一个测试。 因此，在工作流程的开头，会话上放置一个令牌，最后我从会话中删除此令牌。 当我按下后退按钮时，我检查令牌是否不存在并创建facelet中使用的属性的新实例。从transaction_done.xhtml页面到transaction_confirm.xhtml，它可以工作：facelet显示一个带有错误消息的空表单;但是当我再次按下后退按钮进入transaction_register.xhtml页面时，页面会显示旧值并显示错误消息。

我调试代码，第6阶段的属性是一个新实例，所以我不明白为什么寄存器页面会检索旧值。我还注意到，如果我手动删除chrome中的jsessionid，旧值就会消失。 我也不是说当我按下工作流开始时的值的后退按钮时，注册页面上的视图状态不同。

这个测试因此在chrome中进行，默认情况下调用后退按钮上的服务器。 FireFox不会调用服务器，它会默认显示缓存中的页面。 我知道我必须把一个像无缓存这样的值的过滤器...但我想理解为什么它从完成确认页面而不是从确认到注册页面。

我把托管bean的代码和3 .xhtml。

放在一起

提前感谢您的帮助。

一个。 ManagedBean

@ManagedBean
@RequestScoped
public class TransactionBean implements Serializable {
    private ITransactionService transactionService;
    private VirtualDbAccountRepository accountRepository;
    private TransferTransaction currentItem;
    private List<TransferTransaction> transactionList;
    private List<SelectItem> accounts;
    private String id;
    private String nextOutcome;
    private static final String INIT_VIEW = "/home.xhtml";
    private static final String REGISTER_VIEW = "/transaction_register.xhtml";
    private static final String CONFIRM_VIEW = "/transaction_confirm.xhtml";
    private static final String DONE_VIEW = "/transaction_done.xhtml";
    private static final String LISTING_VIEW = "/transaction_listing.xhtml";
    private static final String CURRENT_ITEM = "currentItem";
    private static final String TOKEN = "token";
    private static final String CURRENT_ID = "currentId";

    public TransactionBean() {
        log();

    }

    @PostConstruct
    public void init() throws IOException {
        log();
        transactionService = TransactionService.getInstance();
        accountRepository = new VirtualDbAccountRepository();
        handleByViewId(FacesUtil.getViewId());
    }

    private void handleByViewId(String viewId) throws IOException {
        System.out.println("The ViewState value is: "
                + FacesUtil.getHttpServletRequest().getParameter(
                        "javax.faces.ViewState"));
        log();
        if (viewId.equals(INIT_VIEW))
            handleInitView();
        if (viewId.equals(REGISTER_VIEW))
            handleRegisterView();
        if (viewId.equals(CONFIRM_VIEW))
            handleConfirmView();
        if (viewId.equals(DONE_VIEW))
            handleDoneView();
        if (viewId.equals(LISTING_VIEW))
            handleListingView();
    }

    private void handleInitView() {
        FacesUtil.getSessionMap().put(CURRENT_ITEM, new TransferTransaction());
        FacesUtil.getSessionMap().put(TOKEN, TokenUtil.getRandomHexString());
    }   

    private void handleRegisterView() throws IOException {
        log();
        if (!FacesUtil.getFacesContext().isPostback()) {
            // to handle edit on confirmation page
            currentItem = (TransferTransaction) FacesUtil.getSessionMap().get(
                    CURRENT_ITEM);
            String token = (String) FacesUtil.getSessionMap().get(TOKEN);
            // only create new instance if token equals null.
            if (null == token) {
                currentItem = new TransferTransaction();                
                handleErrorPage();              
            }
            FacesUtil.getSessionMap().put(CURRENT_ITEM, currentItem);
            FacesUtil.getSessionMap()
                    .put(TOKEN, TokenUtil.getRandomHexString());
        } else
            currentItem = (TransferTransaction) FacesUtil.getSessionMap().get(
                    CURRENT_ITEM);
        fillSelectItems();
    }

    private void handleConfirmView() throws IOException {
        log();
        currentItem = (TransferTransaction) FacesUtil.getSessionMap().get(
                CURRENT_ITEM);
        String token = (String) FacesUtil.getSessionMap().get(TOKEN);
        if (null == token) {
            currentItem = new TransferTransaction();
            handleErrorPage();
        }
    }

    private void handleErrorPage() throws IOException {
        FacesUtil.getFacesContext().addMessage(
                null,
                new FacesMessage(FacesMessage.SEVERITY_INFO,
                        "The transaction has already been executed.",
                        "The transaction has already been executed."));

    }

    private void handleDoneView() {
        log();
        id = (String) FacesUtil.getSessionMap().get(CURRENT_ID);
        currentItem = transactionService.find(id);
    }

    private void handleListingView() {
        log();
        transactionList = new ArrayList<TransferTransaction>();
        transactionList = VirtualDbTransferTransactionRepository.getInstance()
                .list();
    }

    private void fillSelectItems() {
        log();
        accounts = new ArrayList<SelectItem>();
        Collection<Account> values = accountRepository.list();
        for (Account a : values) {
            SelectItem sItem = new SelectItem(a, a.getAccountId()); // value,
                                                                    // label
            accounts.add(sItem);
        }
    }

    public String initNewTransaction() {
        return "transaction_register?faces-redirect=true";
    }

    public String register() {
        log();
        String outcome = null;
        // to handle back button
        if (null != nextOutcome)
            outcome = nextOutcome;
        else
            outcome = "transaction_confirm?faces-redirect=true";
        return outcome;
    }

    public String preEdit(String id) {
        log();
        String outcome = null;
        currentItem = transactionService.find(id);
        FacesUtil.getSessionMap().put(CURRENT_ITEM, currentItem);
        FacesUtil.getSessionMap().put(TOKEN, TokenUtil.getRandomHexString());
        outcome = "transaction_register?faces-redirect=true";
        return outcome;
    }

    public String add() {
        log();
        String outcome = null;
        TransactionResult transactionResult = transactionService
                .addTransaction(currentItem);
        if (!transactionResult.getStatusCodes().isEmpty()) {
            List<StatusCode> statusCodes = transactionResult.getStatusCodes();
            for (StatusCode statusCode : statusCodes) {
                FacesUtil.getFacesContext().addMessage(
                        null,
                        new FacesMessage(FacesMessage.SEVERITY_INFO, statusCode
                                .getStatus(), statusCode.getCode()));
            }
            outcome = "transaction_confirm?faces-redirect=true";
        } else {
            // FacesUtil.getSessionMap().put(CURRENT_ITEM, null);
            // CURRENT_ID is used to handle done page
            FacesUtil.getSessionMap().put(CURRENT_ID,
                    transactionResult.getModel().getId().toString());
            FacesUtil.getSessionMap().put(TOKEN, null);
            outcome = "transaction_done?faces-redirect=true";
            // transactionList.add(transactionResult.getModel());
        }

        return outcome;
    }

    public String modifyDate() {
        log();
        String outcome = null;
        TransactionResult transactionResult = transactionService
                .modifyTransaction(currentItem.getId(), currentItem.getDate());
        if (!transactionResult.getStatusCodes().isEmpty()) {
            List<StatusCode> statusCodes = transactionResult.getStatusCodes();
            for (StatusCode statusCode : statusCodes) {
                FacesUtil.getFacesContext().addMessage(
                        null,
                        new FacesMessage(FacesMessage.SEVERITY_INFO, statusCode
                                .getStatus(), statusCode.getCode()));
            }
            outcome = "transaction_confirm?faces-redirect=true";

        } else {
            // FacesUtil.getSessionMap().put(CURRENT_ITEM, null);
            // CURRENT_ID is used to handle done page
            FacesUtil.getSessionMap().put(CURRENT_ID,
                    transactionResult.getModel().getId().toString());
            // outcome = "transaction_listing?faces-redirect=true";
            outcome = "transaction_done?faces-redirect=true";
        }
        return outcome;
    }



    public TransferTransaction getCurrentItem() {
        log();
        return currentItem;
    }

    public void setCurrentItem(TransferTransaction currentItem) {
        this.currentItem = currentItem;
    }

    public List<TransferTransaction> getTransactionList() {
        return transactionList;
    }

    public List<SelectItem> getAccounts() {
        log();
        return accounts;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public void log() {
        PhaseId currentPhaseId = FacesContext.getCurrentInstance()
                .getCurrentPhaseId();
        System.out.println("+++ "
                + Thread.currentThread().getStackTrace()[2].getMethodName()
                + " in phase : " + currentPhaseId.getOrdinal() + " at : "
                + new UtilDate().getTime());
    }


}

B中。页

1.B。 transaction_register.xhtml

<h:body>
    <h:form>
        <h2>Home Bank</h2>
        <h4>Enter a new transaction</h4>
        <table>
            <tr>
                <td>Debit Account Number</td>
                <td>
                    <h:selectOneMenu id="debitAccount" value="#{transactionBean.currentItem.fromAccount}" 
                        disabled="#{transactionBean.currentItem.id != '-1'}"
                        required="true" requiredMessage="Debit Account must be selected.">
                        <f:selectItem  noSelectionOption="true" itemLabel="--------------"/>
                        <f:selectItems value="#{transactionBean.accounts}" />       
                        <f:converter converterId="transferTransactionConverter" />             
                    </h:selectOneMenu>

                </td>
            </tr>
            <tr>
                <td>Credit Account Number</td>
                <td>
                    <h:selectOneMenu id="creditAccount" value="#{transactionBean.currentItem.toAccount}" 
                        disabled="#{transactionBean.currentItem.id != '-1'}"
                        required="true" requiredMessage="Credit Account must be selected.">
                       <f:selectItem  noSelectionOption="true" itemLabel="--------------"/>
                       <f:selectItems value="#{transactionBean.accounts}" />    
                       <f:converter converterId="transferTransactionConverter" />                      
                    </h:selectOneMenu>

                </td>
            </tr>
            <tr>
                <td>Amount</td>
                <td>
                    <h:inputText value="#{transactionBean.currentItem.amount}" disabled="#{transactionBean.currentItem.id != '-1'}" ></h:inputText>
                </td>
            </tr>
            <h:panelGroup rendered="#{transactionBean.currentItem.id != '-1'}">
                <tr>
                    <td>Execution date</td>
                    <td>
                        <h:inputText value="#{transactionBean.currentItem.date}">
                            <f:convertDateTime pattern="dd-MM-yyyy" />
                        </h:inputText>
                    </td>
                </tr>
            </h:panelGroup>
        </table>
        <p>
            <h:commandLink value="Create Transaction" action="#{transactionBean.register}" />           
        </p>
    </h:form>
</h:body>
</html>

2.B。 transaction_confirm.xhtml

<h:body>
    <h2>Home Bank</h2>
    <h4>Confirm new transaction</h4>
    <h:messages showSummary="true" />
    <table>
        <tr>
            <td>Debit Account Number :</td>
            <td><h:outputText label="Debit Account Number"
                    value="#{transactionBean.currentItem.fromAccount.accountId}" /></td>
        </tr>
        <tr>
            <td>Credit Account Number :</td>
            <td><h:outputText label="Credit Account Number"
                    value="#{transactionBean.currentItem.toAccount.accountId}" /></td>
        </tr>
        <tr>
            <td>Amount :</td>
            <td><h:outputText label="Amount"
                    value="#{transactionBean.currentItem.amount}" /></td>
        </tr>
        <h:panelGroup rendered="#{transactionBean.currentItem.id != '-1'}">
            <tr>
                <td>Execution date</td>
                <td><h:outputText value="#{transactionBean.currentItem.date}">
                        <f:convertDateTime pattern="dd-MM-yyyy" />
                    </h:outputText></td>
            </tr>
        </h:panelGroup>
    </table>
    <h:form>
        <div>
            <h:link value="Edit" outcome="transaction_register?faces-redirect=true&amp;includeViewParams=true" />
        </div>
        <h:panelGroup rendered="#{transactionBean.currentItem.id eq '-1'}">
            <div>
                <h:commandButton value="Confirm" action="#{transactionBean.add}" />
            </div>  
        </h:panelGroup>     

        <h:panelGroup rendered="#{transactionBean.currentItem.id gt '-1'}">
            <div>
                <h:commandButton value="Confirm date modification" action="#{transactionBean.modifyDate}" />
            </div>
        </h:panelGroup>     

    </h:form>
</h:body>
</html>

3.B。 transaction_done.xhtml

<h:body>
    <h:form>
        <h2>Home Bank</h2>
        <h4>new transaction is executed.</h4>
        <h:messages />
        <table>
            <tr>
                <td>Debit Account Number :</td>
                <td><h:outputText label="Debit Account Number"
                        value="#{transactionBean.currentItem.fromAccount.accountId}" /></td>
            </tr>
            <tr>
                <td>Credit Account Number :</td>
                <td><h:outputText label="Credit Account Number" value="#{transactionBean.currentItem.toAccount}"  converter="transferTransactionConverter" /></td>
            </tr>
            <tr>
                <td>Amount :</td>
                <td><h:outputText label="Amount" value="#{transactionBean.currentItem.amount}" /></td>
            </tr>

        </table>
        <br/>
        <h:link outcome="home.xhtml" value="Menu" />
    </h:form>
</h:body>
</html>