图片上传

一、在form中写入属性enctype = “multipart/form-data”

1.用以设置表单的MIME编码，默认情况，这个编码格式是application/x-www-form-urlencoded，不能用于文件上传；只有使用了multipart/form-data，才能完整的传递文件数据，完成图片的上传。

<form id="showDataForm" class="layui-form" enctype="multipart/form-data" onsubmit="return PostData()">

二、用ajax提交

$.ajax({
                type: "POST",
                url: '',
                data: formData,
                timeout: 6000,
                async: false,
                cache: false,
                contentType: false,
                processData: false,
                success: function (msg) {
                    setTimeout(function () {
                        $("#scbtn").attr("disabled", false);//将提交按钮解除为可点击
                        layer.msg('提交成功', {
                            time: 1000
                        }, function () {
                            window.location.href = "xx.html";
                        });
                    },1000);

                },
                error: function (msg) {
                    layer.msg('提交超时，请检查您的网络连接！');
                    $("#scbtn").attr("disabled", false);
                }
            });
            return false;

3、后台接收代码

private File file;//与前端name一致

private String fileFileName;//接收的名字
    public File getFile() {
        return file;
    }

    public void setFile(File file) {
        this.file = file;
    }

    public String getFileFileName() {
        return fileFileName;
    }

    public void setFileFileName(String fileFileName) {
        this.fileFileName = fileFileName;
    }

    public static int getSecondTimestamp(Date date){//将上传的图片名字改为yy-mm-dd格式
        if (null == date) {
            return 0;
        }
        String timestamp = String.valueOf(date.getTime());
        int length = timestamp.length();
        if (length > 3) {
            return Integer.valueOf(timestamp.substring(0,length-3));
        } else {
            return 0;
        }
    }

    public String add() throws Exception {
        Date date=new Date();
        if(file != null){
            String path = ServletActionContext.getServletContext().getRealPath("/upload");//服务器项目根路径
            File filePath = new File(path);
            if(!filePath.exists()){
                filePath.mkdir();
            }
            String format = fileFileName.split("\\.")[1];
            File diskFile = new File(path + File.separator
                    + String.valueOf(getSecondTimestamp(date))+"."+format);
            FileUtils.copyFile(file, diskFile);
            casCase.setFurImage(String.valueOf(getSecondTimestamp(date))+"."+format);//图片名字
        }
    }