AjaxFileUploader 实现稳健上传

由于项目需求在上传头像是需要使用异步上传文件，在上传的过程中需要对文件进行校验：规则如下：宽度和高

度大于200，宽高比要小于2，大小小于2M。

    我这里使用的是AjaxFileUploader这个组件，服务器使用Struts处理文件。

    实例：

<form action="" id="imageForm" enctype="multipart/form-data" method="POST">
    <input type="file" name="userPhoto" id="userPhoto">
    <input type="button" value="上传" id="shangchuan">
</form>

    这里需要引入两个js文件：jQuery、ajaxfileUpload

<script type="text/javascript" src="${basePath }/resource/js/plugin/jquery-1.6.min.js"></script>
 <script type="text/javascript" src="${basePath }/resource/js/grzx/ajaxfileupload.js"></script>

   js文件：

//上传头像
    $("#shangchuan").click(function(){
        var file = $("#userPhoto").val();
        if(file==""){
            alert("请选择上传的头像");
            return;
        }
        else{
            //判断上传的文件的格式是否正确
            var fileType = file.substring(file.lastIndexOf(".")+1);
            if(fileType!="png"&&fileType!="jpg"){
                alert("上传文件格式错误");
                return;
            }
            else{
                var url = "/symh/user/uploadPhoto_uploadPhoto.action?nowtime="+new Date().getTime();
                $.ajaxFileUpload({
                    url:url,
                    secureuri:false,
                    fileElementId:"userPhoto",        //file的id
                        dataType:"text",                  //返回数据类型为文本
                    success:function(data,status){
                        if(data=="1"){
                            alert("请上传宽度大于200像素和高度大于200像素的图片");
                        }
                        else if(data=="2"){
                            alert("请上传宽高比不超过2的图片");
                        }
                        else if(data=="3"){
                            alert("请上传文件大小不大于2M的图片");
                        }
                        else{
                            $("#uploadImage").hide();
                            $("#srcImg").attr("src",data);
                            $("#previewImg").attr("src",data);
                            $("#cutImage").show();
                            $("#bigImage").val(data);
                            cutImage();         //截取头像
                        }
                    }
                })
            }
        }
    })

    后台处理程序：UploadPhotoAction.java

public class UploadPhotoAction {
    private File userPhoto;
    private String userPhotoContentType;
    private String userPhotoFileName;

    public File getUserPhoto() {
        return userPhoto;
    }

    public void setUserPhoto(File userPhoto) {
        this.userPhoto = userPhoto;
    }

    public String getUserPhotoContentType() {
        return userPhotoContentType;
    }

    public void setUserPhotoContentType(String userPhotoContentType) {
        this.userPhotoContentType = userPhotoContentType;
    }

    public String getUserPhotoFileName() {
        return userPhotoFileName;
    }

    public void setUserPhotoFileName(String userPhotoFileName) {
        this.userPhotoFileName = userPhotoFileName;
    }

    /**
     * 用户上传图像
     */
    public void uploadPhoto(){
        try {
            HttpServletResponse response = (HttpServletResponse) ActionContext.getContext().get(ServletActionContext.HTTP_RESPONSE);
            response.setCharacterEncoding("UTF-8");

            FileInputStream fis1 = new FileInputStream(getUserPhoto());         //保存文件
            FileInputStream fis2 = new FileInputStream(getUserPhoto());        //判断文件
            int i = this.checkImage(fis2);
            if(i==1){
                response.getWriter().print("1");
            }
            else if(i==2){
                response.getWriter().print("2");
            }
            else if(i==3){
                response.getWriter().print("3");
            }
            else {   //文件正确、上传
                //得到文件名
                String photoName = getPhotoName(getUserPhotoFileName());

                FileOutputStream fos = new FileOutputStream(getSavePath()+"\\"+photoName);
                byte[] buffer = new byte[1024];
                int len = 0;
                while ((len = fis1.read(buffer))>0) {
                    fos.write(buffer,0,len);
                }
                //处理文件路径,便于在前台显示
                String imagPathString = dealPath(getSavePath()+"\\"+photoName);
                response.getWriter().print(imagPathString);

            }
        }
        catch (IOException e) {
            e.printStackTrace();
        }

    }

    /**
     * 重新命名头像名称:用户编号+头像后缀
     */
    public String getPhotoName(String photoName){
        //获取用户
        HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get(ServletActionContext.HTTP_REQUEST);
        UserBean userBean = (UserBean) request.getSession().getAttribute("userBean");

        //获取文件的后缀
        String[] strings = photoName.split("\\.");
        String hz = strings[1];

        //构建文件名
        String fileName = userBean.getUserId()+"."+hz;
        return fileName;
    }

    /**
     * 获取上传路径
     */
    public String getSavePath(){
        return ServletActionContext.getServletContext().getRealPath("upload/photos");
    }

    /**
     * 判断上传的头像是否合法
     * 规则：宽度和高度大于200、宽高比小于2、大小小于2M
     * 宽度或者高度<200 返回1
     * 宽高比>2 返回2
     * 大小大于2M 返回 3
     * 正确 返回 0
     */
    public int checkImage(FileInputStream fis){
        try {
            BufferedImage image = ImageIO.read(fis);
            double width = image.getWidth();
            double height = image.getHeight();
            if(width<200||height<200){
                return 1;
            }
            else if(width/height>2){
                return 2;
            }
            else if(fis.available()/(1024*1024)>2){
                return 3;
            }
            else {
                return 0;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return 1;
    }

    /**
     * 处理头像路径
     */
    public String dealPath(String path){
        String[] strings = path.split("\\\\");
        String string2 = "/";
        for (int i = strings.length-4; i < strings.length; i++) {
            if(i==strings.length-1){
                string2 = string2+strings[i];
            }
            else {
                string2 = string2+strings[i]+"/";
            }

        }
        return string2;
    }
}