jsf在方法表达式中传递参数在ViewScoped bean中失败 [英] jsf passing parameters in a method expression failes in ViewScoped bean

问题描述

我有一个以ViewScoped bean为后盾的jsf页面，其中列出了一堆如下所示的交易

I have jsf page backed by a ViewScoped bean which lists a bunch of transactions like below

<ui:repeat value="#{transactions_byaccount.pageList}" var="item">
            <tr class="dataRow">
                <td class="dataCell cltdtransactionsdatetransaction">
                      <h:outputText value="#{item.datetransaction}" >
                        <f:convertDateTime pattern="EEE dd-MMM-yyyy HH:mm" />
                      </h:outputText>
                </td>
                ...
                ...

                <td colspan="2">
                    <span class="pagerDBspan" style="font-weight: bold;">
                        <h:commandLink action="#{transactions_byaccount.updateCategory('', item)}" >
                            <h:outputText value="Update"></h:outputText>        
                            <f:param name="pageNo" value="#{param.pageNo}" />
                            <f:param name="accountId" value="#{param.accountId}" />
                            <f:param name="sortOrder" value="#{param.sortOrder}" />
                            <f:param name="orderColumn" value="#{param.orderColumn}" />                                                                         
                        </h:commandLink>
                    </span>                                         
                </td>

当用户导航到页面时，链接将accountId作为参数传入，该参数映射到如下所示的bean上的托管属性

when a user navigates to the page, the link has the accountId passed in as a parameter which is mapped to a managed property on the bean like below

@ManagedProperty("#{param.accountId}")
private int accountId;

这时调用方法#{transactions_byaccount.updateCategory(''，item)}传递'item'即可.

at this point calls to the method #{transactions_byaccount.updateCategory('', item)} passing 'item' works as expected.

用户还可以通过选择绑定到上方accountId字段的页面上的下拉菜单并单击刷新按钮来更改帐户ID，该按钮将调用相关的DAO来获取所选帐户的交易列表.但是，当用户单击按钮以调用#{transactions_byaccount.updateCategory(''，item)}时，我没有列出新帐户中的项目，而是使用了第一个帐户列表中的项目.

the user is also able to change the account id by selecting a drop down on the page which is bound to the accountId field above and clicking a refresh button which will call the relevant DAO to get a list of transactions of the selected account. However when the user clicks on the button to call #{transactions_byaccount.updateCategory('', item)} does not list me the item from the new account, it uses the item from the list of the first account.

问题似乎出在JSF生命周期的还原位.

It appears the problem is at the point of the restore bit of the JSF lifecycle.

任何帮助将不胜感激.如有需要，将添加更多详细信息.

Any help would be appreciated. Will add more details if needed.

谢谢 玛尼

我的豆子

package applogic.transactions;

import java.sql.Connection;
import java.util.ArrayList;
import java.util.List;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.RequestScoped;
import javax.faces.bean.ViewScoped;
import javax.faces.model.SelectItem;

import applogic.Conns;

import finance.bean.TransactionsListBean;
import finance.dao.AccountsDAO;
import finance.dao.TransactionsDAO;
import finance.daobase.BusinessDAO;
import finance.model.Accounts;
import finance.model.Transactions;
import java.io.Serializable;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

@ManagedBean(name = "transactions_byaccount")
@ViewScoped
public class Transactions_Byaccount extends TransactionsListBean implements Serializable {
    List<Transactions> resultList;

    boolean initialized;

    @ManagedProperty("#{param.accountId}")
    private int accountId;

    public SelectItem[] accountsSelections;

    @ManagedProperty("#{param.sortOrder}")
    private int sortOrder;

    public SelectItem[] sortOrderSelections;

    @ManagedProperty("#{param.orderColumn}")
    private int orderColumn;

    public SelectItem[] orderColumnSelections;

    public Transactions_Byaccount() {
         Connection cons = Conns.getConFinanceDB();
         List<Accounts> accountsList = AccountsDAO.List(cons);
         List<SelectItem> listOfAccountsSelectItems = new
         ArrayList<SelectItem>();

         for( Accounts temp : accountsList ) {
             listOfAccountsSelectItems.add(new SelectItem(temp.getId(), temp.getTitle()));
         }

         accountsSelections = listOfAccountsSelectItems.toArray(new SelectItem[listOfAccountsSelectItems.size()]);

         List<SelectItem> sortOrderList = new ArrayList<SelectItem>();
         sortOrderList.add(new SelectItem(1, "Asc"));
         sortOrderList.add(new SelectItem(2, "Desc"));       
         sortOrderSelections = sortOrderList.toArray(new SelectItem[sortOrderList.size()]);

         List<SelectItem> orderColumnList = new ArrayList<SelectItem>();
         orderColumnList.add(new SelectItem(1, "Transaction Date"));
         orderColumnList.add(new SelectItem(2, "Action Date"));      
         orderColumnList.add(new SelectItem(3, "Reconciled Date"));
         orderColumnSelections = orderColumnList.toArray(new SelectItem[orderColumnList.size()]);
    }

    public String updateCategories(String redirectURL) {
        String result = redirectURL;

        Connection cons = Conns.getConFinanceDB();
        for( Transactions temp : (List<Transactions>)this.getPageList() )
            TransactionsDAO.Update(cons, temp);

        resultList = null;

        if( redirectURL != null && redirectURL.length() == 0 )
            redirectURL = null;

        return redirectURL;
    }

    public String updateCategory(String redirectURL, Transactions arg) {
        String result = redirectURL;

        Connection cons = Conns.getConFinanceDB();
        TransactionsDAO.Update(cons, arg);

        resultList = null;

        if( redirectURL != null && redirectURL.length() == 0 )
            redirectURL = null;

        return result;
    }

    @PostConstruct
    public void refresh() {
        Connection con = Conns.getConFinanceDB();
        resultList = TransactionsDAO.ListByaccount(con, accountId, getCurrentPageNo(), getPageSize(), orderColumn, sortOrder);
        initialized = true;

    }

    public void reload() {
        Connection con = Conns.getConFinanceDB();
        resultList = TransactionsDAO.ListByaccount(con, accountId, getCurrentPageNo(), getPageSize(), orderColumn, sortOrder);
        initialized = true;

    }

    public String reload(String returnUrl) {
        Connection con = Conns.getConFinanceDB();
        resultList = TransactionsDAO.ListByaccount(con, accountId, getCurrentPageNo(), getPageSize(), orderColumn, sortOrder);
        initialized = true;     
        return returnUrl;
    }

    public Object getPageList() {


        return resultList;
    }

    public int getMaxCount() {
        Connection con = Conns.getConFinanceDB();
        int result = TransactionsDAO.CountByaccount(con, accountId);
        return result;
    }

    public int getAccountId() {
        return accountId;
    }

    public void setAccountId(int accountId) {
        this.accountId = accountId;
    }

    public SelectItem[] getAccountsSelections() {
        return accountsSelections;
    }

    public void setAccountsSelections(SelectItem[] accountsSelections) {
        this.accountsSelections = accountsSelections;
    }

    public int getSortOrder() {
        return sortOrder;
    }

    public void setSortOrder(int sortOrder) {
        this.sortOrder = sortOrder;
    }

    public SelectItem[] getSortOrderSelections() {
        return sortOrderSelections;
    }

    public void setSortOrderSelections(SelectItem[] sortOrderSelections) {
        this.sortOrderSelections = sortOrderSelections;
    }

    public int getOrderColumn() {
        return orderColumn;
    }

    public void setOrderColumn(int orderColumn) {
        this.orderColumn = orderColumn;
    }

    public SelectItem[] getOrderColumnSelections() {
        return orderColumnSelections;
    }

    public void setOrderColumnSelections(SelectItem[] orderColumnSelections) {
        this.orderColumnSelections = orderColumnSelections;
    }   

    public boolean isInitialized() {
        return initialized;
    }

    public void setInitialized(boolean initialized) {
        this.initialized = initialized;
    }

    public List<Transactions> getResultList() {
        return resultList;
    }

    public void setResultList(List<Transactions> resultList) {
        this.resultList = resultList;
    }
}

现在是我的页面

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:t="http://myfaces.apache.org/tomahawk"
    xmlns:f="http://java.sun.com/jsf/core" xml:lang="en" lang="en">


<ui:composition template="/WEB-INF/templates/template_main.xhtml">
    <ui:param name="title" value="transactions"></ui:param>

    <ui:define name="operationalbar">
        <div>
            <span>
                <h:selectOneMenu value="#{transactions_byaccount.accountId}" >
                    <f:selectItems value="#{transactions_byaccount.accountsSelections}"/>
                </h:selectOneMenu>
            </span>
            <span>
                <h:commandLink action="#{transactions_byaccount.reload('')}">
                    <h:outputText value="Reload"></h:outputText>
                    <f:param name="pageNo" value="#{param.pageNo}" />
                    <f:param name="accountId" value="#{param.accountId}" />
                    <f:param name="sortOrder" value="#{param.sortOrder}" />
                    <f:param name="orderColumn" value="#{param.orderColumn}" />
                </h:commandLink>
            </span>         
            <span>
                <h:commandLink action="#{transactions_byaccount.updateCategories('')}">
                    <h:outputText value="Update Categories"></h:outputText>
                    <f:param name="pageNo" value="#{param.pageNo}" />
                    <f:param name="accountId" value="#{param.accountId}" />
                    <f:param name="sortOrder" value="#{param.sortOrder}" />
                    <f:param name="orderColumn" value="#{param.orderColumn}" />
                </h:commandLink>        
            </span>
        </div>
    </ui:define>

    <ui:define name="pagingbar">
        <div>
            <span>
                <h:commandLink title="Go to page first page" >
                    <h:outputText value="first"></h:outputText>
                        <f:param name="pageNo" value="#{transactions_byaccount.firstPage}" />
                        <f:param name="accountId" value="#{param.accountId}" />
                        <f:param name="sortOrder" value="#{param.sortOrder}" />
                        <f:param name="orderColumn" value="#{param.orderColumn}" />             
                </h:commandLink>
            </span>
            <span>
                <h:commandLink title="Go to page prev page">
                    <h:outputText value="prev"></h:outputText>
                        <f:param name="pageNo" value="#{transactions_byaccount.prevPage}" />
                        <f:param name="accountId" value="#{param.accountId}" />
                        <f:param name="sortOrder" value="#{param.sortOrder}" />
                        <f:param name="orderColumn" value="#{param.orderColumn}" />
                </h:commandLink>

            </span>
                <ui:repeat value="#{transactions_byaccount.pages}" var="item">
                    <span style="font-weight: #{item == transactions_byaccount.currentPageNo ? 'bold' : 'lighter' }">
                        <h:commandLink>
                            <h:outputText value="#{item}"></h:outputText>
                            <f:param name="pageNo" value="#{item}" />
                            <f:param name="accountId" value="#{param.accountId}" />
                            <f:param name="sortOrder" value="#{param.sortOrder}" />
                            <f:param name="orderColumn" value="#{param.orderColumn}" />

                        </h:commandLink>
                    </span>
                </ui:repeat>                

            <span>
                <h:commandLink title="Go to page next page">
                    <h:outputText value="next"></h:outputText>
                        <f:param name="pageNo" value="#{transactions_byaccount.nextPage}" />
                        <f:param name="accountId" value="#{param.accountId}" />
                        <f:param name="sortOrder" value="#{param.sortOrder}" />
                        <f:param name="orderColumn" value="#{param.orderColumn}" />
                </h:commandLink>
            </span>
            <span>
                <h:commandLink title="Go to page last page">
                    <h:outputText value="last"></h:outputText>
                        <f:param name="pageNo" value="#{transactions_byaccount.lastPage}" />
                        <f:param name="accountId" value="#{param.accountId}" />
                        <f:param name="sortOrder" value="#{param.sortOrder}" />
                        <f:param name="orderColumn" value="#{param.orderColumn}" />

                </h:commandLink>                
            </span>         
        </div>
        <div class="currentPagerIndex">

        </div>
    </ui:define>
    <ui:define name="maincontent">
        <table class="datatable">
            <thead>
                <tr class="headRow">
                    <td>datetransaction</td>
                    <td>description</td>
                    <td>amount</td>
                    <td>Edit</td>
                    <td>Delete</td>
                </tr>
            </thead>
            <ui:repeat value="#{transactions_byaccount.pageList}" var="item">
                <tr class="dataRow">
                    <td class="dataCell cltdtransactionsdatetransaction">
                          <h:outputText value="#{item.datetransaction}" >
                            <f:convertDateTime pattern="EEE dd-MMM-yyyy HH:mm" />
                          </h:outputText>
                    </td>
                    <td class="dataCell cltdtransactionsdescription">#{item.description}</td>
                    <td class="dataCell cltdtransactionsamount">#{item.amount}</td>
                    <td style="width: 45px">
                        <span class="pagerDBspan" style="font-weight: bold;">                   
                            <h:link outcome="transactions_edit" style="font-weight: bold;">
                                <h:outputText value="Edit"></h:outputText>
                                <f:param name="pageNo" value="#{param.pageNo}" />
                                <f:param name="itemId" value="#{item.id}" />
                            </h:link>
                        </span>                 
                    </td>
                    <td style="width: 45px">
                        <span class="pagerDBspan" style="font-weight: bold;">
                            <h:link  outcome="transactions_edit" >
                                <h:outputText value="Delete"></h:outputText>
                                <f:param name="pageNo" value="#{param.pageNo}" />
                                <f:param name="itemId" value="#{item.id}" />
                                <f:param name="deleteFlag" value="true" />                                  
                            </h:link>       
                        </span>                 
                    </td>
                </tr>
                <tr class="dataRow">
                    <td class="dataCell"></td>
                    <td class="dataCell" colspan="2">
                        <h:selectOneMenu value="#{item.fkCategoriesId}" >
                            <f:selectItems value="#{categories_edit.categories}"/>
                        </h:selectOneMenu>
                    </td>
                    <td colspan="2">
                        <span class="pagerDBspan" style="font-weight: bold;">
                            <h:commandLink action="#{transactions_byaccount.updateCategory('', item)}" >
                                <h:outputText value="Update"></h:outputText>        
                                <f:param name="pageNo" value="#{param.pageNo}" />
                                <f:param name="accountId" value="#{param.accountId}" />
                                <f:param name="sortOrder" value="#{param.sortOrder}" />
                                <f:param name="orderColumn" value="#{param.orderColumn}" />                                                                         
                            </h:commandLink>
                        </span>                                         
                    </td>
                </tr>
                <tr>
                    <td class="cssBottomLine" colspan="0"></td>
                </tr>                   
            </ui:repeat>
        </table>
    </ui:define>

    <ui:define name="bottomoperationalbarhost">
    </ui:define>

</ui:composition>
</html>

推荐答案

与表单显示过程相比，#{transactions_byaccount.pageList}在表单提交过程中发生了不兼容的更改时，就会发生这种情况.

That will happen when the #{transactions_byaccount.pageList} has incompatibly changed during processing of the form submit as compared to how it was during displaying the form.

在处理表单提交的新HTTP请求期间，JSF将在其上重申以找到调用的动作并准备#{item}以便通过它.请注意，因此在呈现HTML表单以供显示的HTTP请求期间未准备好此代码.

During the new HTTP request of processing the form submit, JSF will reiterate over it to find the action invoked and to prepare the #{item} in order to pass it. Note that this is thus not prepared during the HTTP request of rendering the HTML form for display.

此问题表明您正在基于过时(或太新)的变量初始化#{transactions_byaccount.pageList}，该变量导致其不兼容地更改.你不应该那样做.您应该重写bean逻辑，以便它在回发时初始化与显示期间完全相同的列表，然后仅在实际调用了操作(因此，在action方法内部)时才对其进行更改.

This problem indicates that you're initializing #{transactions_byaccount.pageList} based on an outdated (or a too new) variable which caused it to incompatibly change. You should not do that. You should rewrite your bean logic as such that it initializes on postback exactly the same list as it was during display and then change it only when the action has actually been invoked (thus, inside the action method).

鉴于您正在使用视图作用域的bean，实际上应该已经对其进行了设置，因为它实际上会记住后续请求的所有属性.也许您正在列表的getter方法中执行初始化.您根本不应该在getter方法中执行业务逻辑.您应该在(post)构造函数或操作方法中执行此操作.

Given that you're using a view scoped bean, you should actually already be set as it actually remembers all properties for subsequent requests. Perhaps you're performing initialization in the getter method of the list. You should not be performing business logic in getter methods at all. You should do that in (post)constructor or action method.

这篇关于jsf在方法表达式中传递参数在ViewScoped bean中失败的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！