1导入struts2-blank.war所有jar包：\struts-2.3.4\apps\struts2-blank.war

单个文件上传

upload.jsp

<s:form action="upload2.action" method="post" theme="simple" enctype="multipart/form-data">
<tr>
       <td id="more">
             选择上传文件:<s:file name="file"></s:file><br>
             <s:submit type="button" value="submit"/>
         </td>
  </tr>
</s:form>

struts.xml

 <package name="struts2" extends="struts-default">
    <action name="upload2"class="com.hloytax.wg.upload?.UploadAction1">
           <result name="success">/success.jsp</result>
            <interceptor-ref name="fileUpload">
                 <param name="maximumSize">409600</param> //上传文件大小设置
                // <!--allowedTypes (可选) - 以逗号分割的contentType类型列表(例如text/html), <param name="contentType"> application/txt; </param>            <param name="allowedTypes">
                 </param>
             </interceptor-ref>
             <interceptor-ref name="defaultStack"></interceptor-ref>
        </action>
   </package>

UploadAction1.action

public class UploadAction1 extends ActionSupport {

    /**
     *
     */

    private static final long serialVersionUID = 1L;

    private File file;
      //文件名称
    private String fileFileName;  

    //文件类型
    private String fileContentType;
    //注意：文件名称和文件类型的名称前缀必须相同，
    省略get set 方法 

    @Override
    public String execute() throws Exception{     

        //获取需要上传文件的文件路径
        File uploadFile=new File(ServletActionContext.getServletContext().getRealPath("uploadFile"));
        //判断文件是否上传，如果上传的话将会创建该目录
        if(!uploadFile.exists()){
            uploadFile.mkdir(); //创建该目录
        }  

        /*//第一种文件上传的方法
        //声明文件输入流，为输入流指定文件路径
        FileInputStream input=new FileInputStream(file);
        //获取输出流，获取文件的文件地址及名称
        FileOutputStream out=new FileOutputStream(uploadFile + "\\" +fileFileName);  

        try{
            byte[] b=new byte[1024];//每次写入的大小
            int i=0;
            while((i=input.read(b))>0){
                out.write(b,0,i);
            }
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            input.close();
            out.close();
        }
          */

        //第二种文件上传的方法
        //FileUtils.copyFile(file,new File(uploadFile+"\\"+fileFileName));
       // FileUtils.copyFile(file,new File(uploadFile,fileFileName));
       // System.out.println(uploadFile);

        //第三种方法
      BufferedReader bReader=new BufferedReader(new InputStreamReader(new FileInputStream(file)));
      BufferedWriter bWriter=new BufferedWriter(new OutputStreamWriter(new FileOutputStream(uploadFile+"\\"+fileFileName)));
      System.out.println(uploadFile);
      try{
          char[] str=new char[1024];
          int i=0;
          while((i=bReader.read(str))>0){
              bWriter.write(str,0,i);
          }
      }catch(Exception e){
          e.printStackTrace();
      }finally{
         bReader.close();
          bWriter.close();
          uploadFile.delete();
      }  

        return SUCCESS;
    }
  

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    id="WebApp_ID" version="2.5">
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

多文件上传：

private List<File> file;
private List<String> fileContentType;
private List<String> fileFileName;private String savePath;
省略get  set 方法   上传方法  参照单文件上传@Override    public String execute() throws Exception {        List<File> files= getFile();        if (files !=null) {                for (int i = 0; i < files.size(); i++) {                    FileOutputStream fos = new FileOutputStream(getSavePath() + "\\" + getFileFileName().get(i));                    //建立上传文件的输入流                    System.out.println(getSavePath());                    FileInputStream fis = new FileInputStream(files.get(i));

        byte[] buffer = new byte[1024];        int len = 0;        while ((len = fis.read(buffer)) > 0) {             fos.write(buffer, 0, len);         }         fis.close();         fos.close();     } }      return SUCCESS;                    }

    /**     * 返回上传文件保存的位置     *      * @return     * @throws Exception     */    public String getSavePath() throws Exception {        return ServletActionContext.getServletContext().getRealPath(savePath);    }    public void setSavePath(String savePath) {        this.savePath = savePath;    }