文件上传工具类

package zz.homework.util;

import java.io.File;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FilenameUtils;



/**
 * @author Administrator
 * 上传文件工具
 */
public class UpLoadUtils {
	@SuppressWarnings("unchecked")
	public static Map<String,String> upload(HttpServletRequest req){
		// 创建一个Map集合 用来存放所有的参数数据
		HashMap<String,String> hashMap = new HashMap<String,String>();
		try {
			//创建工具对象
			DiskFileItemFactory dff = new DiskFileItemFactory();
			
			//创建上传工具
			ServletFileUpload up = new ServletFileUpload(dff);
			
			//限制上传文件的大小
			up.setFileSizeMax(1024*1024);
			
			// 解析请求中的二进制数据 返回一个List集合
			List<FileItem> list = up.parseRequest(req);
			for (FileItem fi : list) {
				if(fi.isFormField()){
					//普通字段
					hashMap.put(fi.getFieldName(),fi.getString("utf-8"));
				}else{
					//限制文件类型为需要的
					String ct = fi.getContentType();
					if(!ct.startsWith("image/")){
						throw new Exception("请选择图片上传！！");
					}
					//获取到后缀名称
					String exName = FilenameUtils.getExtension(fi.getName());
					//当前时间毫秒数作为随机数
					String readomName = ""+System.currentTimeMillis();
					//设置文件名
					String realPath = req.getServletContext().getRealPath("/headImg");
					//将文件名的反斜杠转换为正斜杠
					realPath = realPath.replace("\\","/");
					//命名
					fi.write(new File(realPath+"/"+readomName+"."+exName));
					//执行DAO操作 保存到数据库
					hashMap.put("headImg","headImg/"+readomName+"."+exName);
				}
			}
			//提示
			req.setAttribute("msg","上传成功！！");
		} catch (FileSizeLimitExceededException e) {
			req.setAttribute("msg","文件大小请勿超过1M！！");
		} catch (Exception e) {
			req.setAttribute("msg","注册失败！！");
		}
		return hashMap;
	}
}