转：EasyUI上传图片，前台预览，后台读取

原文：https://blog.csdn.net/u010137431/article/details/46554767

背景

Spring MVC + EasyUI

前台上传图片，并预览

下面是jsp的内容，form表单

ava 
<form id="upload_form" enctype="multipart/form-data" action="upload_deal.do" method="post">
        <input class="easyui-filebox" style="width:300px" data-options='onChange:change_photo' id="file_upload" name="file_upload2"/><br/> 
        <input type="submit" value="提交" /> <br/>
    </form>
    <div id="Imgdiv">
        <img id="Img" width="200px" height="200px"/>
    </div>

对应调用JS如下

java
function change_photo(){
        PreviewImage($("input[name='file_upload2']")[0], 'Img', 'Imgdiv');
    }

　　其中PreviewImage方法是借用网上大神的代码，这里写链接内容

后台

首先要在Spring-servlet.xml中添加与文件上传相关的配置,这里的100000是图片大小（byte）

java
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="100000"/>
    </bean>

Action部分

java
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="100000"/>
    </bean>
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Action部分

java
@Controller
public class PictureTest {

    @Resource HibernateTemplate hibernateTemplate;

    @RequestMapping("/upload_deal")
    public ModelAndView upload_deal(
            @RequestParam(value="file_upload", required=false) MultipartFile file, 
            HttpServletRequest request, HttpServletResponse response) throws IOException{
        savePicture(file, request);//保存图片

        List<Picture> pics = (List<Picture>)hibernateTemplate.find("from Picture");
        ModelAndView mav = new ModelAndView();
        mav.addObject("photo", pics.get(0).getPhoto_path());
        mav.setViewName("/Test/showPicture");
        return mav;
    }


    //文件保存到服务器上
    protected void savePicture(MultipartFile file, HttpServletRequest request)
            throws IOException, FileNotFoundException {
        String ImagePath = request.getSession().getServletContext().getRealPath("/static/img");
        File targetfile = new File(ImagePath, file.getOriginalFilename());
        Date date = new Date(System.currentTimeMillis());
        if(targetfile.exists()){
            String[] s = file.getOriginalFilename().split("\\.");
            s[0] += date.getTime();
            targetfile = new File(ImagePath, s[0] + "." + s[1]);
        }
        InputStream ins = file.getInputStream();
        FileOutputStream fos = new FileOutputStream(targetfile);

        byte b[] = new byte[1024];
        int temp = 0;

        while((temp = ins.read(b)) != -1){
            fos.write(b, 0, temp);
        }

        fos.close();
        ins.close();
    }
}

附：

function PreviewImage(fileObj,imgPreviewId,divPreviewId){  
    var allowExtention=".jpg,.bmp,.gif,.png";//允许上传文件的后缀名document.getElementById("hfAllowPicSuffix").value;  
    var extention=fileObj.value.substring(fileObj.value.lastIndexOf(".")+1).toLowerCase();              
    var browserVersion= window.navigator.userAgent.toUpperCase();  
    if(allowExtention.indexOf(extention)>-1){   
        if(fileObj.files){//HTML5实现预览，兼容chrome、火狐7+等  
            if(window.FileReader){  
                var reader = new FileReader();   
                reader.onload = function(e){  
                    document.getElementById(imgPreviewId).setAttribute("src",e.target.result);  
                }    
                reader.readAsDataURL(fileObj.files[0]);  
            }else if(browserVersion.indexOf("SAFARI")>-1){  
                alert("不支持Safari6.0以下浏览器的图片预览!");  
            }  
        }else if (browserVersion.indexOf("MSIE")>-1){  
            if(browserVersion.indexOf("MSIE 6")>-1){//ie6  
                document.getElementById(imgPreviewId).setAttribute("src",fileObj.value);  
            }else{//ie[7-9]  
                fileObj.select();  
                if(browserVersion.indexOf("MSIE 9")>-1)  
                    fileObj.blur();//不加上document.selection.createRange().text在ie9会拒绝访问  
                var newPreview =document.getElementById(divPreviewId+"New");  
                if(newPreview==null){  
                    newPreview =document.createElement("div");  
                    newPreview.setAttribute("id",divPreviewId+"New");  
                    newPreview.style.width = document.getElementById(imgPreviewId).width+"px";  
                    newPreview.style.height = document.getElementById(imgPreviewId).height+"px";  
                    newPreview.style.border="solid 1px #d2e2e2";  
                }  
                newPreview.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";                              
                var tempDivPreview=document.getElementById(divPreviewId);  
                tempDivPreview.parentNode.insertBefore(newPreview,tempDivPreview);  
                tempDivPreview.style.display="none";                      
            }  
        }else if(browserVersion.indexOf("FIREFOX")>-1){//firefox  
            var firefoxVersion= parseFloat(browserVersion.toLowerCase().match(/firefox\/([\d.]+)/)[1]);  
            if(firefoxVersion<7){//firefox7以下版本  
                document.getElementById(imgPreviewId).setAttribute("src",fileObj.files[0].getAsDataURL());  
            }else{//firefox7.0+                      
                document.getElementById(imgPreviewId).setAttribute("src",window.URL.createObjectURL(fileObj.files[0]));  
            }  
        }else{  
            document.getElementById(imgPreviewId).setAttribute("src",fileObj.value);  
        }           
    }else{  
        alert("仅支持"+allowExtention+"为后缀名的文件!");  
        fileObj.value="";//清空选中文件  
        if(browserVersion.indexOf("MSIE")>-1){                          
            fileObj.select();  
            document.selection.clear();  
        }                  
        fileObj.outerHTML=fileObj.outerHTML;  
    }  
}

在浏览器里预览本地图片，正常情况下，firefox ,chrome 可以直接预览 本地图片 img.src ,单IE 里不行，因为img.src没有读取本地文件的权限。之前想过用 video、flash 控件等，现在发现一个好东西 ，IE 下 的滤镜也可以。不知道微软是怎么想的，img.src 读取不了 ，filter可以 。本身是是在网上找的 。自己做一个收藏。如果侵权，就删除掉