body> 
  form action="" enctype="multipart/form-data"> 
    h2> 
      多文件上传 
    /h2> 
    input type="file" id="file1" name="file" /> 
    /br> 
    input type="file" id="file2" name="file" /> 
    /br> 
    input type="file" id="file3" name="file" /> 
    /br> 
    span> 
      table id="down"> 
      /table> 
    /span> 
    /br> 
    input type="button" onclick="fileUpload();" value="上传"> 
  /form> 
/body> 
script type="text/javascript"> 
  function fileUpload() { 
    var files = ['file1','file2','file3']; //将上传三个文件 ID 分别为file2,file2,file3 
    $.ajaxFileUpload( { 
      url : 'fileUploadAction',   //用于文件上传的服务器端请求地址  
      secureuri : false,      //一般设置为false  
      fileElementId : files,    //文件上传的id属性 input type="file" id="file" name="file" />  
      dataType : 'json',      //返回值类型 一般设置为json  
      success : function(data, status) { 
        var fileNames = data.fileFileName; //返回的文件名  
        var filePaths = data.filePath;   //返回的文件地址  
        for(var i=0;idata.fileFileName.length;i++){ 
          //将上传后的文件 添加到页面中 以进行下载 
          $("#down").after("tr>td height='25'>"+fileNames[i]+ 
              "/td>td>a href='downloadFile?downloadFilePath="+filePaths[i]+"'>下载/a>/td>/tr>") 
        } 
      } 
    }) 
  } 
/script> 

var oldElement = jQuery('#' + fileElementId); 
var newElement = jQuery(oldElement).clone(); 
jQuery(oldElement).attr('id', fileId); 
jQuery(oldElement).before(newElement); 
jQuery(oldElement).appendTo(form); 

for(var i in fileElementId){  
  var oldElement = jQuery('#' + fileElementId[i]);  
  var newElement = jQuery(oldElement).clone();  
  jQuery(oldElement).attr('id', fileId);  
  jQuery(oldElement).before(newElement);  
  jQuery(oldElement).appendTo(form);  
}  

public class FileAction { 
  private File[] file;       //文件  
  private String[] fileFileName;  //文件名   
  private String[] filePath;    //文件路径 
  private String downloadFilePath; //文件下载路径 
  private InputStream inputStream;  
  /** 
   * 文件上传 
   * @return 
   */ 
  public String fileUpload() { 
    String path = ServletActionContext.getServletContext().getRealPath("/upload"); 
    File file = new File(path); // 判断文件夹是否存在,如果不存在则创建文件夹 
    if (!file.exists()) { 
      file.mkdir(); 
    } 
    try { 
      if (this.file != null) { 
        File f[] = this.getFile(); 
        filePath = new String[f.length]; 
        for (int i = 0; i  f.length; i++) { 
          String fileName = java.util.UUID.randomUUID().toString(); // 采用时间+UUID的方式随即命名 
          String name = fileName + fileFileName[i].substring(fileFileName[i].lastIndexOf(".")); //保存在硬盘中的文件名 
          FileInputStream inputStream = new FileInputStream(f[i]); 
          FileOutputStream outputStream = new FileOutputStream(path+ "\\" + name); 
          byte[] buf = new byte[1024]; 
          int length = 0; 
          while ((length = inputStream.read(buf)) != -1) { 
            outputStream.write(buf, 0, length); 
          } 
          inputStream.close(); 
          outputStream.flush(); 
          //文件保存的完整路径 
          // 如：D:\tomcat6\webapps\struts_ajaxfileupload\\upload\a0be14a1-f99e-4239-b54c-b37c3083134a.png 
          filePath[i] = path + "\\" + name; 
        } 
      } 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
    return "success"; 
  } 
  /** 
   * 文件下载 
   * @return 
   */ 
  public String downloadFile() { 
    String path = downloadFilePath; 
    HttpServletResponse response = ServletActionContext.getResponse(); 
    try { 
      // path是指欲下载的文件的路径。 
      File file = new File(path); 
      // 取得文件名。 
      String filename = file.getName(); 
      // 以流的形式下载文件。 
      InputStream fis = new BufferedInputStream(new FileInputStream(path)); 
      byte[] buffer = new byte[fis.available()]; 
      fis.read(buffer); 
      fis.close(); 
      // 清空response 
      response.reset(); 
      // 设置response的Header 
      String filenameString = new String(filename.getBytes("gbk"),"iso-8859-1"); 
      response.addHeader("Content-Disposition", "attachment;filename="+ filenameString); 
      response.addHeader("Content-Length", "" + file.length()); 
      OutputStream toClient = new BufferedOutputStream(response.getOutputStream()); 
      response.setContentType("application/octet-stream"); 
      toClient.write(buffer); 
      toClient.flush(); 
      toClient.close(); 
    } catch (IOException ex) { 
      ex.printStackTrace(); 
    } 
    return null; 
  } 
  /** 
   * 省略set get方法 
   */ 
} 

!DOCTYPE struts PUBLIC  
  "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" 
  "http://struts.apache.org/dtds/struts-2.0.dtd"> 
struts> 
  package name="ajax_code" extends="json-default"> 
    !-- 文件上传 --> 
    action name="fileUploadAction" class="com.itmyhome.FileAction" method="fileUpload"> 
      result type="json" name="success"> 
        param name="contentType">text/html/param> 
      /result> 
    /action> 
  /package> 
  package name="jsp_code" extends="struts-default"> 
    !-- 文件下载 -->    
    action name="downloadFile" class="com.itmyhome.FileAction" method="downloadFile">   
      result type="stream">   
         param name="contentType">application/octet-stream/param>   
         param name="inputName">inputStream/param>   
         param name="contentDisposition">attachment;filename=${fileName}/param>   
         param name="bufferSize">4096/param>   
      /result>   
    /action>  
  /package> 
/struts>