Use ajaxFileUpload for image upload

Front-end part

Using ajaxFileUpload is mainly to upload files asynchronously, without opening a new page for uploading!
Since segmentfault cannot upload files, the code of the file ajaxFileUpload.js is at the bottom of this article:
Since the file ajaxFileUpload has not been updated for a long time, handleError: function(s, xhr, status, e) has been added. To handle the error, the

front-end code is as follows: The accept attribute in the first input is to limit the uploaded file attributes. This attribute can be removed from other files

Refer to two js files

 <script src="jquery-1.7.1.js" type="text/javascript"></script>
 <script src="ajaxfileupload.js" type="text/javascript"></script>

Upload button:

<input  type="file" id="upload" name="imagefile" accept="image/png,image/gif"  />
<input  type="button"  value="上传" onclick="return ajaxFileUpload();"/>

js code:

    //图片上传
    function ajaxFileUpload()
    {
         
        $.ajaxFileUpload({
                url:'/ai/app/uploadImage',//用于文件上传的服务器端请求地址
                secureuri:false ,//一般设置为false
                fileElementId:&#39;upload&#39;,//文件上传控件的id属性  <input type="file" id="upload" name="upload" />
                dataType: &#39;text&#39;,//返回值类型 一般设置为json
                success: function (message)  //服务器成功响应处理函数
                {
                    layer.alert(message);
                    $("#tool_icon").val(message);
                },
                error: function (data, status, e)//服务器响应失败处理函数
                {
                    alert(e);
                }
            });
        return false;
    }

Backend part

The spring framework used by this project needs to configure beans to accept uploaded files

<!-- 上传文件拦截，设置最大上传文件大小   10M=10*1024*1024(B)=10485760 bytes -->  
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">  
        <property name="maxUploadSize" value="10485760" />  
    </bean>

Backend code

@ResponseBody
    @RequestMapping(value="/uploadImage",method=RequestMethod.POST)
    public String uploadImage(HttpServletRequest request,@RequestParam("imagefile") MultipartFile file) throws IOException{
       String getOriginalFilename = null;
       logger.debug("文件原名: " + getOriginalFilename);
       logger.debug("文件名称: " + file.getName());
       logger.debug("文件长度: " + file.getSize());
       logger.debug("文件类型: " + file.getContentType());
       if( file.isEmpty()){
          logger.error("upload image--------------------------------->failed");
          return "please select a image";
       }
       /**文件在服务器中的实际路径*/
      
       String realPath = request.getSession().getServletContext().getRealPath("/upload");  
       logger.debug("realPath---------------------------------------->"+realPath);
       logger.debug("getOriginalFilename----------------------------->"+file.getOriginalFilename());
       
       /**写入地址中*/
       FileUtils.copyInputStreamToFile(file.getInputStream(), new File(realPath,file.getOriginalFilename()));
       
       /**使用原生方法*/
       /* byte[] bytes = file.getBytes();
       BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(new File("/ai/images/icons/toolLogo/demo.png")));
       stream.write(bytes);
       stream.close();*/
       /**返回文件在服务器中的地址，用于存储入库*/
       
       String resultUrl = "/ai/upload/"+file.getOriginalFilename();
       logger.debug("upload image file result----------------------->"+resultUrl);
       return resultUrl;
    }

ajaxFileUpload.js source code

// JavaScript Document
jQuery.extend({

    createUploadIframe: function(id, uri)
 {
   //create frame
            var frameId = 'jUploadFrame' + id;
            
            if(window.ActiveXObject) {
                var io = document.createElement(&#39;<iframe id="&#39; + frameId + &#39;" name="&#39; + frameId + &#39;" />&#39;);
                if(typeof uri== &#39;boolean&#39;){
                    io.src = &#39;javascript:false&#39;;
                }
                else if(typeof uri== &#39;string&#39;){
                    io.src = uri;
                }
            }
            else {
                var io = document.createElement(&#39;iframe&#39;);
                io.id = frameId;
                io.name = frameId;
            }
            io.style.position = &#39;absolute&#39;;
            io.style.top = &#39;-1000px&#39;;
            io.style.left = &#39;-1000px&#39;;

            document.body.appendChild(io);

            return io;   
    },
    createUploadForm: function(id, fileElementId)
 {
  //create form 
  var formId = &#39;jUploadForm&#39; + id;
  var fileId = &#39;jUploadFile&#39; + id;
  var form = jQuery(&#39;<form  action="" method="POST" name="&#39; + formId + &#39;" id="&#39; + formId + &#39;" enctype="multipart/form-data"></form>&#39;); 
  var oldElement = jQuery(&#39;#&#39; + fileElementId);
  var newElement = jQuery(oldElement).clone();
  jQuery(oldElement).attr(&#39;id&#39;, fileId);
  jQuery(oldElement).before(newElement);
  jQuery(oldElement).appendTo(form);
  //set attributes
  jQuery(form).css(&#39;position&#39;, &#39;absolute&#39;);
  jQuery(form).css(&#39;top&#39;, &#39;-1200px&#39;);
  jQuery(form).css(&#39;left&#39;, &#39;-1200px&#39;);
  jQuery(form).appendTo(&#39;body&#39;);  
  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 = &#39;jUploadFrame&#39; + id;
  var formId = &#39;jUploadForm&#39; + 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(&#39;#&#39; + formId);
   jQuery(form).attr(&#39;action&#39;, s.url);
   jQuery(form).attr(&#39;method&#39;, &#39;POST&#39;);
   jQuery(form).attr(&#39;target&#39;, frameId);
            if(form.encoding)
   {
                form.encoding = &#39;multipart/form-data&#39;;    
            }
            else
   {    
                form.enctype = &#39;multipart/form-data&#39;;
            }   
            jQuery(form).submit();

        } catch(e) 
  {   
            jQuery.handleError(s, xml, null, e);
        }
        if(window.attachEvent){
            document.getElementById(frameId).attachEvent(&#39;onload&#39;, uploadCallback);
        }
        else{
            document.getElementById(frameId).addEventListener(&#39;load&#39;, 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] );  
                }  
    }  
});