@RequestMapping("/upload/image")
public Object uploadFile(@RequestBody JSONObject a) throws IOException {

    File file = null;
    try {
        file = base64ToFile(a.getString("file"));
    } catch (Exception e) {
        e.printStackTrace();
    }
    String url = FileUtil.uploadFile(file);

    return url;
}


public  File base64ToFile(String base64) throws Exception {
    if(base64.contains("data:image")){
        base64 = base64.substring(base64.indexOf(",")+1);
    }
    base64 = base64.toString().replace("\r\n", "");
    //创建文件目录
    String prefix=".jpeg";
    File file = File.createTempFile(UUID.randomUUID().toString(), prefix);
    BufferedOutputStream bos = null;
    FileOutputStream fos = null;
    try {
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] bytes =  decoder.decodeBuffer(base64);
        fos = new FileOutputStream(file);
        bos = new BufferedOutputStream(fos);
        bos.write(bytes);
    }finally {
        if (bos != null) {
            try {
                bos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (fos != null) {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return file;
}

//上传图片     $('#createImage').on('click',function(){         let param = new FormData(); //创建form对象         let signName = document.getElementById("signName");         let twojz = $('#signName').createSignature();         let blob = dataURItoBlob($('#signName').createSignature());         console.log($('#signName').createSignature());         console.log(blob);         let pmm = {"file":twojz};         let pmmStr = JSON.stringify(pmm);         param.append('file', blob, "--image" + new Date().getTime() + "client_signature.png");         let pararar = {"fileStream":blob};         let par = JSON.stringify(pararar);         $.ajax({                 url:"http://localhost:8080/upload/image" , // 请求路径                 type:"POST" , //请求方式                 processData : false,                 contentType : "application/json",                 async:false,                 data:pmmStr,                 beforeSend: function (XMLHttpRequest) {                 XMLHttpRequest.setRequestHeader("token", "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJhZG1pbiIsImV4cCI6MTY1MDMwNzg1MH0.ciKm2SQUGbo2Olk01EnmzVnJVdON0VOgULkLP-L5OMM");              },                 success:function (data) {                     alert(data);                 },//响应成功后的回调函数                 error:function () {                     alert("出错啦...")                 },//表示如果请求响应出现错误，会执行的回调函数
                dataType:"text"//设置接受到的响应数据的格式                     });                         });
}); </script>