struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
	<constant name="struts.ui.theme" value=http://www.mamicode.com/"simple">>
BaseAction.java
package com.yl.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;


public class BaseAction extends ActionSupport {

	/**
	 * 序列化ID
	 */
	private static final long serialVersionUID = 1L;

	protected String successResultValue;

	public String getSuccessResultValue() {
		return successResultValue;
	}

	public void setSuccessResultValue(String successResultValue) {
		this.successResultValue = http://www.mamicode.com/successResultValue;>
一个例子action：
package com.yl.action;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.annotation.Resource;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

import com.yl.biz.ImgBiz;
import com.yl.config.SysConfig;
import com.yl.cons.UploadResult;
import com.yl.entity.Img;
import com.yl.util.CipherUtil;

@Component("imgAction")
@Scope("prototype")
/**
 * 图片Action
 */
public class ImgAction extends BaseAction {

	/**
	 * 序列化ID
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * 路径
	 */
	private File upload;

	public File getUpload() {
		return upload;
	}

	public void setUpload(File upload) {
		this.upload = upload;
	}

	/**
	 * 图片实体
	 */
	private Img img;

	public Img getImg() {
		return img;
	}

	public void setImg(Img img) {
		this.img = img;
	}

	/**
	 * 注入
	 */
	@SuppressWarnings("unused")
	@Resource(name = "imgBiz")
	private ImgBiz imgBiz;

	/**
	 * 图片上传
	 * 
	 * @return
	 */
	@SuppressWarnings("deprecation")
	public String uploadFile() {
		@SuppressWarnings("unused")
		String paths = getRequest().getRealPath("/");
		// 判断路径是否为空
		if (this.upload == null || !this.upload.isFile()
				|| !this.upload.canRead()) {
			this.addActionError(UploadResult.NULLFILE.getTitle());
			return SUCCESS;
		}
		try {
			FileInputStream fis = new FileInputStream(this.upload);
			// 获得图片大小
			int fileSize = fis.available();
			// 判断图片大小
			if (fileSize > SysConfig.MAX_FILE_SIZE) {
				this.addActionError(UploadResult.TooLargeFile.getTitle());
			} else {
				// 保存路径
				String path = SysConfig.PUBLIC_PATH;
				// 获取图片名字
				String fileName = this.upload.getName();
				// 判断是否有点
				if (!fileName.contains(".")) {
					this.addActionError(UploadResult.NOTIMG.getTitle());
				}
				// 截取文件类型
				fileName = fileName.substring(fileName.lastIndexOf("."));
				SimpleDateFormat sdf = new SimpleDateFormat(
						"yyyy-MM-dd HH:mm:ss aa");
				// 从新给图片命名
				fileName = CipherUtil.md5Encoding(sdf.format(new Date()))
						+ fileName;
				// 保存图片路径+图片名字
				fileName = path + "\\" + fileName;
				// New一个新的地址.
				File file = new File(fileName);
				// 输出图片到新的地址
				FileOutputStream fos = new FileOutputStream(file);
				int c;
				byte b[] = new byte[4 * 1024];
				while ((c = fis.read(b)) != -1) {
					fos.write(b, 0, c);
				}
				// 关闭相关操作
				fos.flush();
				fis.close();
				// 保存成功信息
				this.addActionError(UploadResult.SUCCESS.getTitle());
			}
		} catch (FileNotFoundException e) {
			// 保存失败信息
			this.addActionError(UploadResult.NULLFILE.getTitle());
			e.printStackTrace();
		} catch (IOException e) {
			// 保存失败信息
			this.addActionError(UploadResult.UPLOADFAIL.getTitle());
			e.printStackTrace();
		}
		// 设置返回页面
		setSuccessResultValue("/index.jsp");
		return SUCCESS;

	}

}

常量：
package com.yl.config;


import org.apache.struts2.ServletActionContext;
import org.springframework.beans.factory.InitializingBean;

/**
 * 图片系统类
 * 
 */
public class SysConfig implements InitializingBean {

	public static Boolean IS_DEBUG = true;
	

	/**
	 * 上传图片大小控制
	 */
	public static int MAX_FILE_SIZE = 1024 * 1024 * 100;

	/**
	 * 上传图片路径控制
	 */
	
	@SuppressWarnings("deprecation")
	public static String PUBLIC_PATH = ServletActionContext.getRequest().getRealPath("/") + "upload";

	private SysConfig() {
	}

	public static boolean isDebug() {
		return IS_DEBUG != null && IS_DEBUG;
	}

	public void setIS_DEBUG(Boolean iS_DEBUG) {
		IS_DEBUG = iS_DEBUG;
	}

	public void afterPropertiesSet() throws Exception {
	}
}

一个错误的结果enum封装，使用见action：
package com.yl.cons;

/**
 * 上传返回标志
 * 
 */
public enum UploadResult {
	SUCCESS((short) 0, "成功"), NULLFILE((short) 1, "找不到文件"), NOTIMG((short) 2,
			"非图片文件"), UPLOADFAIL((short) 3, "上传失败"), TooLargeFile((short) 4,
			"文件过大");
	/**
	 * 错误类型
	 */
	private short type;

	/**
	 * 错误名称
	 */
	private String title;

	private UploadResult(short type, String title) {
		this.type = type;
		this.title = title;
	}

	public short getType() {
		return type;
	}

	public String getTitle() {
		return title;
	}

}