Ajax配合Spring实现文件上传功能代码

由于项目需要,开发一个可以上传图片到服务器的web表单页面。

一、 需求

Web表单页面,可以通过表单上传图片以及其他文字信息。

二、 图片上传的流程

之前没有做过这类页面,通过查询资料。发现比较常见的做法,是先将图片上传到服务器端的某个文件目录下,服务器向前台返回图片的存储路径;之后,前台将图片存储路径以及其他表单信息一起提交到服务器,所有的表单信息存储在数据库中。

三、 方法

由于项目需要,我这里介绍两种图片上传方法,第一种是使用ajax对一个图片直接上传;第二种是先在前台将图片切割为较小的文件,之后使用ajax分别上传图片到服务器,服务器实现对文件的拼接。(方法二适合较大文件的上传)下面我分别对两种方法做介绍。

方法一: 直接上传

1 html页面

<pre><!DOCTYPE html> <head></head> <body> <form action="/PicSubmit/form" method="post" enctype="multipart/form-data" onsubmit="return submit_check()" ></pre><pre><input id = "sid" type = "text" /></pre><pre><pre><input id = "fileImage" type = "file" /></pre><pre><input id = "addressid" type = "hidden" /></pre><pre><input type="button" value="上传图片"font-family: Arial, Helvetica, sans-serif;">" /> </span></pre><pre><input type="submit" value="提交表单" /> <input type="reset" value="重置表单" /> </pre></body></html><p></p> <pre></pre> <br> <pre></pre> 这一部分需要注意的是,form表单的enctype属性必须设置为“multipart/form-data”,在Html5中,如果需要多张图片一起上传,可以在<input type="file"> 标签中,增加multiple属性,例如:<input type="file" id= “fileImage” multiple />。<br> <br> <br> <p></p> <p>2 js</p> <p>(1)js使用ajax提供的ajaxfileupload.js库。这个库使用起来还是比较方便的,和普通的ajax函数使用方法几乎相同。首先,需要ajaxfileupload.js库文件。这里需要注意,我之前在网上下载了一个ajaxfileupload.js文件不能用,浪费了很长时间,我直接把js库文件粘贴到这里,方便分享。</p> <p></p><pre>// JavaScript Document</pre><pre>// ajax file uplaod jQuery.extend({ createUploadIframe: function(id, uri) { //create frame var frameId = 'jUploadFrame' + id; if(window.ActiveXObject) { var io = document.createElement('<iframe />'); if(typeof uri== 'boolean'){ io.src = 'javascript:false'; } else if(typeof uri== 'string'){ io.src = uri; } } else { var io = document.createElement('iframe'); io.id = frameId; io.name = frameId; } io.style.position = 'absolute'; io.style.top = '-1000px'; io.style.left = '-1000px'; document.body.appendChild(io); return io; }, createUploadForm: function(id, fileElementId) { //create form var formId = 'jUploadForm' + id; var fileId = 'jUploadFile' + id; var form = jQuery('<form action="" method="POST" enctype="multipart/form-data"></form>'); var oldElement = jQuery('#' + fileElementId); var newElement = jQuery(oldElement).clone(); jQuery(oldElement).attr('id', fileId); jQuery(oldElement).before(newElement); jQuery(oldElement).appendTo(form); //set attributes jQuery(form).css('position', 'absolute'); jQuery(form).css('top', '-1200px'); jQuery(form).css('left', '-1200px'); jQuery(form).appendTo('body'); return form; }, ajaxFileUpload: function(s) { // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout s = jQuery.extend({}, jQuery.ajaxSettings, s); var id = s.fileElementId; var form = jQuery.createUploadForm(id, s.fileElementId); var io = jQuery.createUploadIframe(id, s.secureuri); var frameId = 'jUploadFrame' + id; var formId = 'jUploadForm' + id; if( s.global && ! jQuery.active++ ) { // Watch for a new set of requests jQuery.event.trigger( "ajaxStart" ); } var requestDone = false; // Create the request object var xml = {}; if( s.global ) { jQuery.event.trigger("ajaxSend", [xml, s]); } var uploadCallback = function(isTimeout) { // Wait for a response to come back var io = document.getElementById(frameId); try { if(io.contentWindow) { xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null; xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document; }else if(io.contentDocument) { xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null; xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document; } }catch(e) { jQuery.handleError(s, xml, null, e); } if( xml || isTimeout == "timeout") { requestDone = true; var status; try { status = isTimeout != "timeout" ? "success" : "error"; // Make sure that the request was successful or notmodified if( status != "error" ) { // process the data (runs the xml through httpData regardless of callback) var data = jQuery.uploadHttpData( xml, s.dataType ); if( s.success ) { // ifa local callback was specified, fire it and pass it the data s.success( data, status ); }; if( s.global ) { // Fire the global callback jQuery.event.trigger( "ajaxSuccess", [xml, s] ); }; } else { jQuery.handleError(s, xml, status); } } catch(e) { status = "error"; jQuery.handleError(s, xml, status, e); }; if( s.global ) { // The request was completed jQuery.event.trigger( "ajaxComplete", [xml, s] ); }; // Handle the global AJAX counter if(s.global && ! --jQuery.active) { jQuery.event.trigger("ajaxStop"); }; if(s.complete) { s.complete(xml, status); } ; jQuery(io).unbind(); setTimeout(function() { try { jQuery(io).remove(); jQuery(form).remove(); } catch(e) { jQuery.handleError(s, xml, null, e); } }, 100); xml = null; }; } // Timeout checker if( s.timeout > 0 ) { setTimeout(function(){ if( !requestDone ) { // Check to see ifthe request is still happening uploadCallback( "timeout" ); } }, s.timeout); } try { var form = jQuery('#' + formId); jQuery(form).attr('action', s.url); jQuery(form).attr('method', 'POST'); jQuery(form).attr('target', frameId); if(form.encoding) { form.encoding = 'multipart/form-data'; } else { form.enctype = 'multipart/form-data'; } jQuery(form).submit(); } catch(e) { jQuery.handleError(s, xml, null, e); } if(window.attachEvent){ document.getElementById(frameId).attachEvent('onload', uploadCallback); } else{ document.getElementById(frameId).addEventListener('load', uploadCallback, false); } return {abort: function () {}}; }, uploadHttpData: function( r, type ) { var data = !type; data = type == "xml" || data ? r.responseXML : r.responseText; // ifthe type is "script", eval it in global context if( type == "script" ) { jQuery.globalEval( data ); } // Get the JavaScript object, ifJSON is used. if( type == "json" ) { eval( "data = " + data ); } // evaluate scripts within html if( type == "html" ) { jQuery("<div>").html(data).evalScripts(); } return data; }, handleError: function( s, xhr, status, e ) { // If a local callback was specified, fire it if ( s.error ) { s.error.call( s.context || s, xhr, status, e ); } // Fire the global callback if ( s.global ) { (s.context ? jQuery(s.context) : jQuery.event).trigger( "ajaxError", [xhr, s, e] ); } } });</pre><p></p> <p><br> </p>

(2)之后调用ajaxfileupload.js库,编写图片上传脚本,这里命名为ajaxfileuplaod_implement.js 

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