在Struts 2中实现文件上传

Struts 2是通过Commons FileUpload文件上传。Commons FileUpload通过将HTTP的数据保存到临时文件夹，然后Struts使用fileUpload拦截器将文件绑定到Action的实例中。从而我们就能够以本地文件方式的操作浏览器上传的文件。

具体实现

前段时间Apache发布了Struts 2.0.6 GA，所以本文的实现是以该版本的Struts作为框架的。以下是例子所依靠类包的列表
清单1 依靠类包的列表

首先，创建文件上传页面FileUpload.jsp，内容如下
%26lt;% @ page language = " Java " contentType = " text/Html; charset=utf-8 " pageEncoding = " utf-8 " %%26gt;
%26lt;% @ taglib prefix = " s " uri = " /struts-tags " %%26gt;

%26lt;! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" %26gt;
%26lt; html XMLns ="http://www.w3.org/1999/xhtml" %26gt;
%26lt; head %26gt;
%26lt; title %26gt; Struts 2 File Upload %26lt;/ title %26gt;
%26lt;/ head %26gt;
%26lt; body %26gt;
%26lt; s:form action ="fileUpload" method ="POST" enctype ="multipart/form-data" %26gt;
%26lt; s:file name ="myFile" label ="Image File" /%26gt;
%26lt; s:textfield name ="caption" label ="Caption" /%26gt;
%26lt; s:submit /%26gt;
%26lt;/ s:form %26gt;
%26lt;/ body %26gt;
%26lt;/ html %26gt;

清单2 FileUpload.jsp
在FileUpload.jsp中，先将表单的提交方式设为POST，然后将enctype设为multipart/form-data，这并没有什么非凡之处。接下来，%26lt;s:file/%26gt;标志将文件上传控件绑定到Action的myFile属性。

其次是FileUploadAction.java代码

package tutorial;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Date;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class FileUploadAction extends ActionSupport {