springmvc + ajaxfileupload 实现异步上传文件（图片）

迷南。 2022-08-07 03:58 303阅读 0赞

最近在做一个项目需要实现异步上传图片，在网上找了很多资料后，采用了ajaxfileupload可以实现，以下是核心代码：

**jsp:**

<div id="uploadPicWindow" class="easyui-window" title="上传图片"  style="width:420px;height:220px;padding:20px;background:#fafafa;" data-options="iconCls:'icon-save',closable:true, collapsible:true,minimizable:true,maximizable:true">
    		<form id="picForm" action="" method="post">
    			<div style="margin-bottom:20px">
    				图片名称:
    				<input type="text" name="name" id="picName" class="easyui-textbox" style="width:80%" data-options="required:true,validType:'stringCheck'"/>
    			</div>
    			<br/>
    			<div style="margin-bottom:20px">
    				选择图片:
    				<input type="file" name="file" id="file" data-options="prompt:'Choose a file...'" style="width:80%"/>
    			</div>
    			<div id="picTip"></div>
    			<div id="formWindowfooterPic1" style="padding:5px;text-align:right;"> 
    				<a href="#" οnclick="submitPic();" class="easyui-linkbutton" data-options="iconCls:'icon-save'">提交</a>
    			</div>
    		</form>
    	</div>

**js:**

//新建或编辑 保存提交
    function submitPic(){
    	if(!$("#picForm").form('validate')){
    		return false;
    	}
    	var projectId = $("#projectId").val();
    	var name=$("#picName").val();
    	var type="1";//展示图片
    	var f = $("#file").val();
    	if(f==null||f==""){
    		$("#picTip").html("<span style='color:Red'>错误提示:上传文件不能为空,请重新选择文件</span>");
    		return false;
    	  }else{
    	   var extname = f.substring(f.lastIndexOf(".")+1,f.length);
    	   extname = extname.toLowerCase();//处理了大小写
    	   if(extname!= "jpeg"&&extname!= "jpg"&&extname!= "gif"&&extname!= "png"){
    		 $("#picTip").html("<span style='color:Red'>错误提示:格式不正确,支持的图片格式为：JPEG、GIF、PNG！</span>");
    	     return false;
    	    }
    	  }
    	 var file = document.getElementById("file").files;  
    	 var size = file[0].size;
    	 if(size>2097152){
    		  $("#picTip").html("<span style='color:Red'>错误提示:所选择的图片太大，图片大小最多支持2M!</span>"); 
    		  return false;
    	  }
    	ajaxFileUploadPic(projectId,name,type);
    }
    
    function ajaxFileUploadPic(projectId,name,type) {
    	$.ajaxFileUpload({
    		url : '${ctx}/projectPic/saveorupdate.jhtml?projectId='+projectId+'&name='+name+'&type='+type, //用于文件上传的服务器端请求地址
    		secureuri : false, //一般设置为false
    		fileElementId : 'file', //文件上传空间的id属性  <input type="file" id="file" name="file" />
    		type : 'post',
    		dataType : 'json', //返回值类型 一般设置为json
    		success : function(data, status) //服务器成功响应处理函数
    		{
    			 $("#picList").datagrid('reload');
    		     $('#uploadPicWindow').window('close');
    		    // alert(data.msg);
    		},
    		error : function(data, status, e)//服务器响应失败处理函数
    		{
    			 $("#picList").datagrid('reload');
    		     $('#uploadPicWindow').window('close');
    		    // alert(data.msg);
    		}
    	});
    	return false;
    }

ajaxfileupload.js

jQuery.extend({
    	
        createUploadIframe: function(id, uri)
    	{
    			//create frame
                var frameId = 'jUploadFrame' + id;
                var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
    			if(window.ActiveXObject)
    			{
                    if(typeof uri== 'boolean'){
    					iframeHtml += ' src="' + 'javascript:false' + '"';
    
                    }
                    else if(typeof uri== 'string'){
    					iframeHtml += ' src="' + uri + '"';
    
                    }	
    			}
    			iframeHtml += ' />';
    			jQuery(iframeHtml).appendTo(document.body);
    
                return jQuery('#' + frameId).get(0);			
        },
        createUploadForm: function(id, fileElementId, data)
    	{
    		//create form	
    		var formId = 'jUploadForm' + id;
    		var fileId = 'jUploadFile' + id;
    		var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');	
    		if(data)
    		{
    			for(var i in data)
    			{
    				jQuery('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(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 = new Date().getTime()        
    		var form = jQuery.createUploadForm(id, s.fileElementId, (typeof(s.data)=='undefined'?false:s.data));
    		var io = jQuery.createUploadIframe(id, s.secureuri);
    		var frameId = 'jUploadFrame' + id;
    		var formId = 'jUploadForm' + id;		
            // Watch for a new set of requests
            if ( s.global && ! jQuery.active++ )
    		{
    			jQuery.event.trigger( "ajaxStart" );
    		}            
            var requestDone = false;
            // Create the request object
            var xml = {}   
            if ( s.global )
                jQuery.event.trigger("ajaxSend", [xml, s]);
            // Wait for a response to come back
            var uploadCallback = function(isTimeout)
    		{			
    			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 a local callback was specified, fire it and pass it the data
                            if ( s.success )
                                s.success( data, status );
        
                            // Fire the global callback
                            if( s.global )
                                jQuery.event.trigger( "ajaxSuccess", [xml, s] );
                        } else
                            jQuery.handleError(s, xml, status);
                    } catch(e) 
    				{
                        status = "error";
                        jQuery.handleError(s, xml, status, e);
                    }
    
                    // The request was completed
                    if( s.global )
                        jQuery.event.trigger( "ajaxComplete", [xml, s] );
    
                    // Handle the global AJAX counter
                    if ( s.global && ! --jQuery.active )
                        jQuery.event.trigger( "ajaxStop" );
    
                    // Process result
                    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(){
                    // Check to see if the request is still happening
                    if( !requestDone ) 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)
    			{
    				jQuery(form).attr('encoding', 'multipart/form-data');      			
                }
                else
    			{	
    				jQuery(form).attr('enctype', 'multipart/form-data');			
                }			
                jQuery(form).submit();
    
            } catch(e) 
    		{			
                jQuery.handleError(s, xml, null, e);
            }
    		
    		jQuery('#' + frameId).load(uploadCallback	);
            return {abort: function () {}};	
    
        },
    
        uploadHttpData: function( r, type ) {
            var data = !type;
            data = type == "xml" || data ? r.responseXML : r.responseText;
            // If the type is "script", eval it in global context
            if ( type == "script" )
                jQuery.globalEval( data );
            // Get the JavaScript object, if JSON 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] );
        			}
        }
     
    })

**注：如果出现**

#  #

jQuery.handleError is not a function

原因是，经测试handlerError只在jquery-1.4.2之前的版本中存在，jquery-1.6 和1.7中都没有这个函数了，因此在1.4.2中将这个函数复制到了ajaxFileUpload.js中，问题解决
    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] );
    		}
    	},
    问题2：一直得到error ，无法执行指定的success方法。通过追踪ajaxFileUpload的执行过程发现，在调用它自身的uploadHttpData函数时，当执行if（type=="json")    eval("data = "+data);
    会抛出异常，导致在处理异常的时候将status = "error" 因此一直执行error方法。
    上网查询，得知eval函数是用来执行一段js代码，而并不是如我所想的反解json串
    eval("data = "+data);的意思是 将data 赋值给 data参数 ，但是当我返回给页面的是一个简单的字符串，比如"OK" ，时，这样写就抛出异常。最后改为 eval("data = \" "+data+" \" ");即将返回的数据用双引号引起来当作字符串，然后赋给 data 。终于成功了。。。

#  #

**action:**

@RequestMapping(value = "/saveorupdate.jhtml")
    	@ResponseBody
    	public synchronized String saveOrUpdate(HttpServletRequest request) throws IOException {
    		DynamicParams params = new DynamicParams(request);
    		String projectId = request.getParameter("projectId");
    		String name = request.getParameter("name");
    		String type = request.getParameter("type");
    		params.put("projectId", projectId);
    		params.put("name", name);
    		params.put("type", type);
    
    		MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
    		MultipartFile file = null;
    		if("1".equals(type)){
    			file = multipartRequest.getFile("file");// 获取上传文件名
    		}else{
    			file = multipartRequest.getFile("attachFile");// 获取上传文件名
    		}
    		ProjectPic projectPic = params.convertToEntity(ProjectPic.class);		
    		projectPicManager.save(projectPic, file.getInputStream());
    		return successMsg();
    	}

**到此一切ok，开始上传文件吧！**