最近做项目发现，在文件上传的过程中，增加进度条，能大大改善用户体验。本例介绍带进度条的文件上传
环境搭建
原生ajax上传带进度条
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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>文件上传 原生ajax上传</title>
<style type="text/css">
.container{
width: 200px;
height: 20px;
background-color: gray;
}
#progress{
height: 20px;
background-color: orange;
display: inline-block;
} </style>
</head>
<body>
<form action="${pageContext.request.contextPath }/upload"
enctype="multipart/form-data" method="post">
上传文件1: <input type="file" name="file1" id="file"><br />
<div class='container'>
<span id="progress"></span>
</div>
</form>
<br>
<button onclick="fileSelected()">文件信息</button><button onclick="uploadFile()">确认上传</button>
<div id="info">
<div id="fileName"></div>
<div id="fileSize"></div>
<div id="fileType"></div>
</div>
<div id="result"></div>
<script>
function fileSelected() {
var file = document.getElementById('file').files[0];
if (file) {
var fileSize = 0;
if (file.size > 1024 * 1024)
fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + 'MB';
else
fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + 'KB';
document.getElementById('fileName').innerHTML = 'Name: ' + file.name;
document.getElementById('fileSize').innerHTML = 'Size: ' + fileSize;
document.getElementById('fileType').innerHTML = 'Type: ' + file.type;
}
}
function uploadFile() {
var fd = new FormData();
fd.append("file", document.getElementById('file').files[0]);
var xhr = new XMLHttpRequest();
xhr.upload.addEventListener("progress", uploadProgress, false);
xhr.addEventListener("load", uploadComplete, false);
xhr.addEventListener("error", uploadFailed, false);
xhr.addEventListener("abort", uploadCanceled, false);
xhr.open("POST", "${pageContext.request.contextPath }/upload");//修改成自己的接口
xhr.send(fd);
} function uploadProgress(evt) {
if (evt.lengthComputable) {
var percent = Math.round(evt.loaded * 100 / evt.total); document.getElementById('progress').innerHTML = percent.toFixed(2) + '%';
document.getElementById('progress').style.width = percent.toFixed(2) + '%';
}
else {
document.getElementById('progress').innerHTML = 'unable to compute';
}
}
function uploadComplete(evt) {
/* 服务器端返回响应时候触发event事件*/
document.getElementById('result').innerHTML = evt.target.responseText;
}
function uploadFailed(evt) {
alert("There was an error attempting to upload the file.");
}
function uploadCanceled(evt) {
alert("The upload has been canceled by the user or the browser dropped the connection.");
}
</script> </body>
</html>
运行效果：
Jquery ajax上传带进度条
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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>文件上传 jquery上传</title>
<script type="text/javascript" src="js/jquery.min.js"></script>
<style type="text/css">
.container{
width: 200px;
height: 20px;
background-color: gray;
}
#progress{
height: 20px;
background-color: orange;
display: inline-block;
} </style>
</head>
<body>
<form action="${pageContext.request.contextPath }/upload"
enctype="multipart/form-data" method="post">
上传文件1: <input type="file" name="file1"><br />
<div class='container'>
<span id="progress"></span>
</div>
</form>
<br>
<button onclick="upload()">确认上传</button>
<div id="info"></div>
<div id="result"></div>
<script>
var totalSize = 0; //绑定所有type=file的元素的onchange事件的处理函数
$(':file').change(function() {
var file = this.files[0]; //假设file标签没打开multiple属性，那么只取第一个文件就行了
name = file.name;
size = file.size;
type = file.type;
url = window.URL.createObjectURL(file); //获取本地文件的url，如果是图片文件，可用于预览图片 totalSize += size;
$("#info").html("文件名：" + name + "<br>文件类型：" + type + "<br>文件大小：" + size + "<br>url: " + url); }); function upload() {
//创建FormData对象，初始化为form表单中的数据。需要添加其他数据可使用formData.append("property", "value");
var formData = new FormData($('form')[0]); //ajax异步上传
$.ajax({
url: "${pageContext.request.contextPath }/upload",
type: "POST",
data: formData,
xhr: function(){ //获取ajaxSettings中的xhr对象，为它的upload属性绑定progress事件的处理函数 myXhr = $.ajaxSettings.xhr();
if(myXhr.upload){ //检查upload属性是否存在
//绑定progress事件的回调函数
myXhr.upload.addEventListener('progress',progressHandlingFunction, false);
}
return myXhr; //xhr对象返回给jQuery使用
},
success: function(result){
$("#result").html(result);
},
contentType: false, //必须false才会自动加上正确的Content-Type
processData: false //必须false才会避开jQuery对 formdata 的默认处理
});
} //上传进度回调函数：
function progressHandlingFunction(e) {
if (e.lengthComputable) {
$('#progress').attr({value : e.loaded, max : e.total}); //更新数据到进度条
var percent = e.loaded/e.total*100;
$('#progress').html(e.loaded + "/" + e.total+" bytes. " + percent.toFixed(2) + "%");
$('#progress').css('width', percent.toFixed(2) + "%");
}
}
</script>
</body>
</html>
运行效果：
