文件上传struts2 实现文件上传功能(4)

2、多文件上传
修改action

     private  List < File >  file;
     private  List < String >  fileFileName;
     private  List < String >  fileContentType;

     public  String execute()  throws  Exception  {
        for (int i = 0; i < file.size(); ++i) {
            InputStream is = new FileInputStream(file.get(i));
            String root = ServletActionContext.getRequest().getRealPath(
                    "/upload");
            File destFile = new File(root, this.getFileFileName().get(i));
            OutputStream os = new FileOutputStream(destFile);
            byte[] buffer = new byte[400];

            int length = 0;

            while ((length = is.read(buffer)) > 0) {
                os.write(buffer, 0, length);
            }
            is.close();
            os.close();
        }
        return SUCCESS;
    }

修改upload3.jsp

                 < tr >
                     < td >
                        file1
                     </ td >
                     < td >
                         < s:file  name ="file" ></ s:file >
                     </ td >
                 </ tr >
                 < tr >
                     < td >
                        file2
                     </ td >
                     < td >
                         < s:file  name ="file" ></ s:file >
                     </ td >
                 </ tr >
                 < tr >
                     < td >
                        file3
                     </ td >
                     < td >
                         < s:file  name ="file" ></ s:file >
                     </ td >
                 </ tr >

结果：




3、任意数量文件上传 
在多文件上传的基础上修改upload3.jsp

         < script  type ="text/javascript" >
        function addMore()
        {
            var td = document.getElementById("more");
            var br = document.createElement("br");
            var input = document.createElement("input");
            var button = document.createElement("input");
            input.type = "file";
            input.name = "file";
            button.type = "button";
            button.value = "Remove";
            button.onclick = function()
            {
                td.removeChild(br);
                td.removeChild(input);
                td.removeChild(button);
            }
            td.appendChild(br);
            td.appendChild(input);
            td.appendChild(button);
        }
     </ script >

                 < tr >
                     < td >
                        file1
                     </ td >
                     < td  id ="more" >
                         < s:file  name ="file" ></ s:file >
                         < input  type ="button"  value ="Add More.."  onclick ="addMore()" >
                     </ td >
                 </ tr >

结果：


（四）文件上传类型、大小的限制
使用struts的拦截器，struts2-core-2.1.6.jar/org.apache.struts2.interceptor.FileUploadInterceptor.class的源码中我们可以看到：

public class FileUploadInterceptor extends AbstractInterceptor {

    private static final long serialVersionUID = -4764627478894962478L;

    protected static final Logger LOG = LoggerFactory.getLogger(FileUploadInterceptor.class);
    private static final String DEFAULT_MESSAGE = "no.message.found";

    protected boolean useActionMessageBundle;

    protected Long maximumSize;
    protected Set < String >  allowedTypesSet = Collections.emptySet();
    protected Set < String >  allowedExtensionsSet = Collections.emptySet();

所以我们只需的struts.xml中配置它的属性allowedTypesSet即可。在action节点中修改拦截器（默认的拦截器中已经有fileUpload拦截器，我们必须提取出来进行参数设置，然后在加上默认的拦截器）。

         < action  name ="upload"  class ="com.test.action.UploadAction" >
             < result  name ="success" > /upload/result3.jsp </ result >
             < result  name ="input" > /upload/upload3.jsp </ result >
             < interceptor-ref  name ="fileUpload" >
                 < param  name ="maximumSize" > 409600 </ param >
                 < param  name ="allowedTypes" >
                    application/vnd.ms-powerpoint
                 </ param >
             </ interceptor-ref >
             < interceptor-ref  name ="defaultStack" ></ interceptor-ref >
         </ action >

其中 < param  name ="allowedTypes" > application/vnd.ms-powerpoint </ param >的allowedTypes的值可在C:\Tomcat 6.0\conf的web.xml文件中查找。

报错信息：

严重: Content - Type not allowed: file  " intrl.txt "   " upload__138d8aca_120b73e9cf4__8000_00000002.tmp "  text / plain

（五）文件的下载
download.jsp

         < s:a  href ="/MyStruts2/download.action" > download </ s:a >

DownloadAction.java

 1 package  com.test.action;
 2
 3 import  java.io.InputStream;
 4
 5 import  org.apache.struts2.ServletActionContext;
 6
 7 import  com.opensymphony.xwork2.ActionSupport;
 8
 9 public   class  DownloadAction  extends  ActionSupport  {
10    public InputStream getDownloadFile() {
11        return ServletActionContext.getServletContext().getResourceAsStream(
12                "/upload/intrl.ppt");
13    }
14
15    @Override
16    public String execute() throws Exception {
17        return SUCCESS;
18    }
19}
20

web.xml中action配置

         < action  name ="download"
            class ="com.test.action.DownloadAction" >
             < result  name ="success"  type ="stream" >
                 < param  name ="contentType" >
                    application/vnd.ms-powerpoint
                 </ param >
                 < param  name ="contentDisposition" >
                    filename="intrl.ppt"
                 </ param >
                 < param  name ="inputName" > downloadFile </ param >
             </ result >
         </ action >

结果：