HTML5拖拽文件到浏览器并实现文件上传下载
先上代码，写的jsp页面，后台是tomcat服务器，所以页面里有一些java的代码，如果后台用其他语言可以无视：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@page import="java.io.*"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>上传、下载文件</title> <style type="text/css"> #filedrag { display: none; font-weight: bold; text-align: center; padding: 1em 0; margin: 1em 0; color: #555; border: 2px dashed #555; border-radius: 7px; cursor: default; } #filedrag.hover { color: #f00; border-color: #f00; border-style: solid; box-shadow: inset 0 3px 4px #888; } </style> </head> <body> <form id="upload" action="UploadServlet" enctype="multipart/form-data" method="post" onsubmit="return upLoad();"> <p> <label for="fileselect">file name:</label><input multiple="true" type="file" id="fileselect" name="fileselect[]" /> <div id="filedrag">或者将文件拖拽到这里</div> <div id="submitbutton"> <input type="submit" value="提交"> </div> </form> <div id="messages"> </div> <% //java代码，显示服务器上可以供下载的文件 File f = new File("G://defggg/"); File[] list = f.listFiles(); for (int i = 0; i < list.length; ++i) { System.out.println(list[i].getName()); out.print("<a href='DownloadServlet?filename=" + list[i].getName() + "'>" + list[i].getName() + "</a><br/>"); } %> <script type="text/javascript"> var upfiles = new Array(); // getElementById function $id(id) { return document.getElementById(id); } // output information function Output(msg) { var m = $id("messages"); m.innerHTML = msg + m.innerHTML; } // file drag hover function FileDragHover(e) { e.stopPropagation(); e.preventDefault(); e.target.className = (e.type == "dragover" ? "hover" : ""); } // file selection function FileSelectHandler(e) { // cancel event and hover styling FileDragHover(e); // fetch FileList object var files = e.target.files || e.dataTransfer.files; // process all File objects for ( var i = 0, f; f = files[i]; i++) { ParseFile(f); upfiles.push(f); } } // output file information function ParseFile(file) { Output("<p>文件信息: <strong>" + file.name + "</strong> 类型: <strong>" + file.type + "</strong> 大小: <strong>" + file.size + "</strong> bytes</p>"); } function upLoad() { if (upfiles[0]) { var xhr = new XMLHttpRequest(); //Ajax异步传输数据 xhr.open("POST", "UploadServlet", true); var formData = new FormData(); for ( var i = 0, f; f = upfiles[i]; i++) { formData.append('myfile', f); } xhr.send(formData); xhr.onreadystatechange=function(e){ history.go(0); //由于这个页面还要显示可以下载的文件，所以需要刷新下页面 } return false; } } // initialize function Init() { var fileselect = $id("fileselect"), filedrag = $id("filedrag"), submitbutton = $id("submitbutton"); // file select fileselect.addEventListener("change", FileSelectHandler, false); // is XHR2 available? var xhr = new XMLHttpRequest(); if (xhr.upload) { // file drop filedrag.addEventListener("dragover", FileDragHover, false); filedrag.addEventListener("dragleave", FileDragHover, false); filedrag.addEventListener("drop", FileSelectHandler, false); filedrag.style.display = "block"; // remove submit button //submitbutton.style.display = "none"; } } // call initialization file if (window.File && window.FileList && window.FileReader) { Init(); } </script> </body> </html>附上后台处理上传下载的servlet，用了smartUpLoad，不能很好的解决中文问题：
package com.hit.software; import java.io.IOException; import javax.servlet.ServletConfig; 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 com.jspsmart.upload.Files; import com.jspsmart.upload.SmartUpload; /** * Servlet implementation class UploadServlet */ @WebServlet("/UploadServlet") public class UploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; private ServletConfig config; final public void init(ServletConfig config) throws ServletException { this.config = config; } /** * @see HttpServlet#HttpServlet() */ public UploadServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse * response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); // String s = request.getParameter("pic"); // System.out.println(s); SmartUpload mySmartUpload = new SmartUpload(); try { mySmartUpload.initialize(config, request, response); mySmartUpload.setMaxFileSize(150 * 1024 * 1024); mySmartUpload.setTotalMaxFileSize(150 * 1024 * 1024); // mySmartUpload.setAllowedFilesList("doc,txt,rar,pdf,png"); mySmartUpload.setDeniedFilesList("exe"); mySmartUpload.upload(); Files f = mySmartUpload.getFiles(); int size = f.getCount(); for (int i = 0; i < size; ++i) { String fileName = mySmartUpload.getFiles().getFile(i) .getFileName(); fileName = new String(fileName.trim().getBytes(), "UTF-8"); //能解决部分中文问题 System.out.println("filename=" + fileName); if (!fileName.equals("")) { String path = "g:/defggg/" + fileName; f.getFile(i).saveAs(path, SmartUpload.SAVE_PHYSICAL); } } } catch (Exception e) { e.printStackTrace(); System.out.println("Unable to upload the file."); System.out.println("Error :" + e.toString()); } response.sendRedirect("index.jsp"); } }package com.hit.software; import java.io.File; import java.io.IOException; import javax.servlet.ServletConfig; 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 javax.servlet.jsp.JspFactory; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.PageContext; import com.jspsmart.upload.SmartUpload; import com.jspsmart.upload.SmartUploadException; /** * Servlet implementation class DownloadServlet */ @WebServlet("/DownloadServlet") public class DownloadServlet extends HttpServlet { private static final long serialVersionUID = 1L; private ServletConfig config; /** * @see HttpServlet#HttpServlet() */ public DownloadServlet() { super(); // TODO Auto-generated constructor stub } final public void init(ServletConfig config) throws ServletException { this.config = config; } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse * response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); String fileName = request.getParameter("filename"); System.out.println("down :"+fileName); if (fileName == null) { response.sendRedirect("index.jsp"); return; } fileName = "G://defggg//" + fileName; File f = new File(fileName); if (f.exists() && f.isFile()) { SmartUpload su = new SmartUpload(); su.initialize(config, request, response); su.setContentDisposition(null); try { su.downloadFile(fileName); } catch (SmartUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); } } else { response.sendRedirect("index.jsp"); return; } } }参考：http://www.sitepoint.com/html5-file-drag-and-drop/
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