文件上传几乎是每个web应用程序的一个必须模块，文件上传的实现需要将表单元素属性enctype的值设置成multipart/form-data，这样使表单数据以二进制编码的方式提交。下面在struts2中提供一种上传文件的方式，供大家参考。
struts2中上传文件必须添加的的jar包：commons-fileupload-x.x.x.jar和common-io-x.x.x.jar
创建一个fileUpAction来处理要上传文件的文件，代码如下：
package cn.test.fileUp;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class fileUpAction extends ActionSupport {
?private static final int BUFFER_SIZE=60*60;
?private File upload;//封装上传文件域的属性
?private String uploadContentType;//封装上传文件的类型
?private String uploadFileName;//封装上传文件名
?private String savePath;//封装文件上传的保存路径
?/**
? *
? * @param source 源文件
? * @param target 目标文件
? * @throws IOException
? */
?private static void copy(File source,File target) throws IOException
?{
??InputStream inputStream=null;
??OutputStream outputStream = null;
??try {
???inputStream=new BufferedInputStream(new FileInputStream(source));
???outputStream=new BufferedOutputStream(new FileOutputStream(target),(int)source.length());
???byte[] buffer=new byte[BUFFER_SIZE];
???int length=0;
???while((length=inputStream.read(buffer))>0)
???{
????outputStream.write(buffer,0,length);
????
???}
??} catch (FileNotFoundException e) {
???// TODO Auto-generated catch block
???e.printStackTrace();
??}
??if(inputStream!=null)
??{
??inputStream.close();
??}
??if(outputStream!=null)
??{
??outputStream.close();
??}
?}
?public String fileUpUI()
?{
??return "fileUpUI";
?}
?@Override
?public String execute() throws Exception {
??// TODO Auto-generated method stub
??String path1=ServletActionContext.getServletContext().getRealPath(this.getSavePath());
??File f = new File(path1);
??if(!f.exists())
??{
???f.mkdirs();
??}
??String path=path1+"\\"+this.getUploadFileName();
??System.out.println(path1);
??File target=new File(path);
??copy(this.upload,target);
??return "fsuccess";
?}
?public File getUpload() {
??return upload;
?}
?public void setUpload(File upload) {
??this.upload = upload;
?}
?public String getUploadContentType() {
??return uploadContentType;
?}
?public void setUploadContentType(String uploadContentType) {
??this.uploadContentType = uploadContentType;
?}
?
?public String getUploadFileName() {
??return uploadFileName;
?}
?public void setUploadFileName(String uploadFileName) {
??this.uploadFileName = uploadFileName;
?}
?public String getSavePath() {
??return savePath;
?}
?public void setSavePath(String savePath) {
??this.savePath = savePath;
?}
?public static int getBufferSize() {
??return BUFFER_SIZE;
?}
}
说明：在上述action中，用upload属性封装上传文件的内容，但却不能获得上传文件的类型和文件名称。因此需要使用uploadContentType来封装上传文件的类型，用uploadFileName来封装上传文件的名字，另外，配置一个savePath来封装文件保存的路径。
struts.xml文件配置如下：
?<action name="file_*" class="cn.test.fileUp.fileUpAction" method="{1}">
??????? <param name="savePath">/upload</param>
??????? <result name="fileUpUI">/WEB-INF/jsp/fileUpUI.jsp</result>
??????? <result name="fsuccess">/WEB-INF/jsp/fsuccess.jsp</result>
??????? </action>
创建fileUpUI.jsp代码如下：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<s:form action="file_execute" namespace="/"?? enctype="multipart/form-data">
<s:file name="upload" label="文件"></s:file>
<s:submit value="确定"></s:submit>
</s:form>
</html>
创建fsuccess.jsp代码如下：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
文件上传成功!
</html>
部署项目，在浏览器中输入：http://localhost:8080/MyWeb/file_fileUpUI，就可以实现上传文件功能。
原文：http://673390302.iteye.com/blog/2291975