在上章節Struts2 文件上傳示例, 用戶允許選擇一個文件並上傳到服務器。在本教程中，您將學習如何允許用戶將多個文件上傳到服務器。

這裏創建一個Web工程：strut2uploadfiles，來演示在多個複選框如何設置的默認值，整個項目的結構如下圖所示：

1. 動作類

在Action類，可以使用列表或數組以存儲上傳的文件。

FileUploadAction.java

package com.yiibai.common.action;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import com.opensymphony.xwork2.ActionSupport;

public class MultipleFileUploadAction extends ActionSupport{

private List<File> fileUpload = new ArrayList<File>();
private List<String> fileUploadContentType = new ArrayList<String>();
private List<String> fileUploadFileName = new ArrayList<String>();

public List<File> getFileUpload() {
    return fileUpload;
}

public void setFileUpload(List<File> fileUpload) {
    this.fileUpload = fileUpload;
}

public List<String> getFileUploadContentType() {
    return fileUploadContentType;
}

public void setFileUploadContentType(List<String> fileUploadContentType) {
    this.fileUploadContentType = fileUploadContentType;
}

public List<String> getFileUploadFileName() {
    return fileUploadFileName;
}

public void setFileUploadFileName(List<String> fileUploadFileName) {
    this.fileUploadFileName = fileUploadFileName;
}

public String upload() throws Exception{

    for (File file: fileUpload) {
        System.out.println("File :" + file);
    }

    for (String fileName: fileUploadFileName) {
        System.out.println("Filename : " + fileName);
    }

    for (String fileContentType: fileUploadContentType) {
        System.out.println("File type : " + fileContentType);
    }

    return SUCCESS;

}

public String display() {
    return NONE;
}

}

2. 結果頁面

使用<s:file>標籤來渲染多文件上傳組件，並設置表單 enctype類型爲「multipart/form-data」.

fileupload.jsp

<%@ taglib prefix="s" uri="/struts-tags" %>

 <constant name="struts.devMode" value="true" />

<package name="default" namespace="/" extends="struts-default">

<action name="multipleFileUploadAction" 
    class="com.yiibai.common.action.MultipleFileUploadAction" 
        method="display">
    <result name="none">pages/multiplefileupload.jsp</result>
</action>

<action name="resultAction" 
     class="com.yiibai.common.action.MultipleFileUploadAction" 
         method="upload">
     <result name="success">pages/result.jsp</result>
</action>