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【转】HTML5拖拽文件到浏览器并实现文件上传下载

2014-03-09 15:13 671 查看

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");

 }

}

本文转自编程中国社区,作者@三公主

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标签:  html5