实现文件上传，以及表单提交成功的回调函数

最近在项目中需要实现图片的上传，并且成功后返回图片上传保存路径，通过查找资料探索研究，实现了项目功能需求，记在这方便自己以后查阅，也为有同样需求的码友分享，功能实现比较简单，如果有好的建议和实现方法，还望多多指教。

[b]主要将实现一下两个功能：[/b]
1、使用commons-fileupload实现文件的上传（包括图片）；
2、使用jquery-form.js实现表单提交成功的回调函数。

页面设计fileupload.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>










			


				

					
				

			

			

				提交
			

	

	 
	

servlet实现：imageUploadServlet.java

package com.system.comtrol;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.sf.json.JSONObject;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;


/**
 * Servlet implementation class ImageUploadServlet
 */
@WebServlet("/servlet/imageUploadServlet")
public class ImageUploadServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#service(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			PrintWriter out = response.getWriter();
			// 文件保存目录路径
			String savePath = request.getServletContext().getRealPath("/")+ "attached";
			// 文件保存目录URL
			String saveUrl = request.getContextPath() + "/attached";
			// 定义允许上传的文件扩展名
			HashMap extMap = new HashMap();
			extMap.put("image", "gif,jpg,jpeg,png,bmp");
			// 最大文件大小
			long maxSize = 1000000;
			response.setContentType("text/html; charset=UTF-8");

			if (!ServletFileUpload.isMultipartContent(request)) {
				out.println(getError("请选择文件。"));
				return;
			}
			// 检查目录
			File uploadDir = new File(savePath);
			if (!uploadDir.isDirectory()) {
				out.println(getError("上传目录不存在。"));
				return;
			}
			// 检查目录写权限
			if (!uploadDir.canWrite()) {
				out.println(getError("上传目录没有写权限。"));
				return;
			}

			String dirName = request.getParameter("dir");
			if (dirName == null) {
				dirName = "image";
			}
			if (!extMap.containsKey(dirName)) {
				out.println(getError("目录名不正确。"));
				return;
			}
			// 创建文件夹
			savePath += dirName + "/";
			saveUrl += dirName + "/";
			File saveDirFile = new File(savePath);
			if (!saveDirFile.exists()) {
				saveDirFile.mkdirs();
			}
			SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
			String ymd = sdf.format(new Date());
			savePath += ymd + "/";
			saveUrl += ymd + "/";
			File dirFile = new File(savePath);
			if (!dirFile.exists()) {
				dirFile.mkdirs();
			}

			FileItemFactory factory = new DiskFileItemFactory();
			ServletFileUpload upload = new ServletFileUpload(factory);
			upload.setHeaderEncoding("UTF-8");
			List items = upload.parseRequest(request);
			Iterator itr = items.iterator();
			while (itr.hasNext()) {
				FileItem item = (FileItem) itr.next();
				String fileName = item.getName();
				if (!item.isFormField()) {
					// 检查文件大小
					if (item.getSize() > maxSize) {
						out.println(getError("上传文件大小超过限制。"));
						return;
					}
					// 检查扩展名
					String fileExt = fileName.substring(fileName.lastIndexOf(".") + 1).toLowerCase();
					if (!Arrays. asList(extMap.get(dirName).split(",")).contains(fileExt)) {
						out.println(getError("上传文件扩展名是不允许的扩展名。\n只允许"	+ extMap.get(dirName) + "格式。"));
						return;
					}

					SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmss");
					String newFileName = df.format(new Date()) + "_" + new Random().nextInt(1000) + "." + fileExt;
					try {
						File uploadedFile = new File(savePath, newFileName);
						item.write(uploadedFile);
					} catch (Exception e) {
						out.println(getError("上传文件失败。"));
						return;
					}

					JSONObject obj = new JSONObject();
					obj.put("error", 0);
					obj.put("url", saveUrl + newFileName);
					out.println(obj.toString());
				}
			}
		} catch (FileUploadException e1) {
			e1.printStackTrace();
		}

	}

	private String getError(String message) {
		JSONObject obj = new JSONObject();
		obj.put("error", 1);
		obj.put("message", message);
		return obj.toString();
	}

}

项目中依赖的主要jar：commons-fileupload-1.2.jar，commons-io-1.4.jar
主要的两个js文件：jquery.min.js，jquery-form.js
这些可以去网上下载，也可以在附件中下载。