通过将模型传递到支持bean，从primefaces数据表中下载文件？

Question

fileUploadDownload.xhtml

    <h:form id="form" enctype="multipart/form-data">
            <p:growl id="growl" sticky="true" showsDetail="true" />
            <div id="header">
                <ui:insert name="header">
                    <ui:include src="/templates/header.xhtml" />
                </ui:insert>
            </div>

            <p:dialog modal="true" widgetVar="statusDialog" header="Status"
                draggable="false" closable="false" resizable="false">
                <p:graphicImage value="/resources/images/ajaxloading.gif" />
            </p:dialog>
            <p:growl id="msgs" showDetail="true" />

            <p:tabView>
                <p:tab title="Upload File">

                </p:tab>

                <p:tab title="Download File">

                    <p:commandButton value="Download" icon="ui-icon-circle-arrow-s"
                        ajax="false"
                        actionListener="#{fileDownloadView.download(fileDownloadView.selectedFile)}">
                        <f:setPropertyActionListener value="#{dfTable}"
                            target="#{fileDownloadView.selectedFile}" />
                    </p:commandButton>

                    <p:dataTable id="downFilesTable" var="dfTable" paginator="true"
                        rows="15" rowsPerPageTemplate="5,10,15,20,25,30"
                        sortBy="#{dfTable.bankName}" expandableRowGroups="true"
                        value="#{copyFilesView.copyFilesModelList}" widgetVar="table"
                        selection="#{fileDownloadView.selectedFile}"
                        rowKey="#{dfTable.fileName}">
                        <f:facet name="header">
                            Copy Output Files
                        </f:facet>

                        <p:column selectionMode="single"
                            style="width:16px;text-align:center" />
                        <p:headerRow>
                            <p:column colspan="5" headerText="Bank Name">
                                <h:outputText value="#{dfTable.bankName}" />
                            </p:column>
                        </p:headerRow>

                        <p:column headerText="Bank Identifier"
                            filterBy="#{dfTable.bankIdentifier}" footerText="contains"
                            filterMatchMode="contains">
                            <h:outputText value="#{dfTable.bankIdentifier}" />
                        </p:column>

                        <p:column headerText="Output File Name"
                            filterBy="#{dfTable.fileName}" footerText="contains"
                            filterMatchMode="contains">
                            <h:outputText value="#{dfTable.fileName}" />
                        </p:column>

                        <p:column headerText="File Type" filterBy="#{dfTable.fileType}"
                            footerText="equals" filterMatchMode="equals">
                            <f:facet name="filter">
                                <p:selectOneButton onchange="PF('table').filter()">
                                    <f:selectItem itemLabel="All" itemValue="" />
                                    <f:selectItem itemLabel="Update" itemValue="Update" />
                                    <f:selectItem itemLabel="Full" itemValue="Full" />
                                </p:selectOneButton>
                            </f:facet>
                            <h:outputText value="#{dfTable.fileType}" />
                        </p:column>

                        <p:column headerText="File Timestamp" sortBy="#{dfTable.timestamp}">
                            <h:outputText value="#{dfTable.timestamp}" />
                        </p:column>

                    </p:dataTable>
                </p:tab>
            </p:tabView>

        </h:form>

FileDownloadView.java

public class FileDownloadView
{
    private CopyFilesModel selectedFile;

    public CopyFilesModel getSelectedFile()
    {
        return selectedFile;
    }

    public void setSelectedFile(CopyFilesModel selectedFile) 
    {
        this.selectedFile = selectedFile;
    }

    public void download(CopyFilesModel selectedFile) throws IOException
    {
        FacesContext fc = FacesContext.getCurrentInstance();
        ExternalContext ec = fc.getExternalContext();
        String filename = selectedFile.getFileName();
    // not sure about the rest of the code... I've tried many different ways...
    }
}

模型

public class CopyFilesModel implements Serializable
{
    private String bankName;
    private String bankIdentifier;
    private String fileName;
    private String fileType;
    private String timestamp;

    // *******************GETTERS & SETTERS *****************************
    public String getBankName() 
    {
        return bankName;
    }
    public void setBankName(String bankName) 
    {
        this.bankName = bankName;
    }
    public String getBankIdentifier() 
    {
        return bankIdentifier;
    }
    public void setBankIdentifier(String bankIdentifier) 
    {
        this.bankIdentifier = bankIdentifier;
    }
    public String getFileName() 
    {
        return fileName;
    }
    public void setFileName(String fileName) 
    {
        this.fileName = fileName;
    }
    public String getFileType() 
    {
        return fileType;
    }
    public void setFileType(String fileType) 
    {
        this.fileType = fileType;
    }
    public String getTimestamp() 
    {
        return timestamp;
    }
    public void setTimestamp(String timestamp)
    {
        this.timestamp = timestamp;
    }  
}

信息

我有一个数据表，该数据表是从另一个xhtml页面的后备bean填充的，因为它们对数据表使用相同的信息。在上面的代码中，我想从数据表中选择一行/文件，然后使用commandButton下载文件。我希望用户选择将文件保存到的位置。有人可以通过将数据表中的对象传递到支持bean的下载方法中，然后将文件保存到用户指定的任何位置，来帮助我从目录/ moe / del / hc / arc / 20180905 / send下载文件吗？该文件的类型为File，看起来像HTUZ001D，没有扩展名。