java实现后台上传压缩图片

控制器的方法
public ResultMap fileUpload(@RequestParam("file") MultipartFile file) {
    String pictureName = DateUtil.getAllTime();
 //获取压缩后的图片名称，随机生成
 String smallerPictureName = UUID.randomUUID().toString();
 try {
 //未压缩前的上传路径
 String fileSavePath = getFileUploadPath() + "/image/" + pictureName + ".jpg";
 File tempFile = new File(fileSavePath);
 file.transferTo(tempFile);
 //压缩后的路径
 String smallFileSavePath = getFileUploadPath()+"/image/"+smallerPictureName+".jpg";
 //获取文件大小 KB
 long size = file.getSize()/1024;
 //判断文件大小对图片质量进行压缩,尺寸不变，范围0.01~1.0,值越低压缩效率越高。图片低于600K不进行压缩
 if(size>=7380){
 Thumbnails.of(fileSavePath).scale(1f).outputQuality(0.01f).toFile(smallFileSavePath);
 tempFile.delete();
 return getResultMap(SUCCESS_CODE,smallerPictureName);
 }else if(size>=4096&&size<7380){
 Thumbnails.of(fileSavePath).scale(1f).outputQuality(0.2f).toFile(smallFileSavePath);
 tempFile.delete();
 return getResultMap(SUCCESS_CODE,smallerPictureName);
 }else if(size>=1024&&size<4096){
 Thumbnails.of(fileSavePath).scale(1f).outputQuality(0.3f).toFile(smallFileSavePath);
 tempFile.delete();
 return getResultMap(SUCCESS_CODE,smallerPictureName);
 }else if(size>=600&&size<1024){
 Thumbnails.of(fileSavePath).scale(1f).outputQuality(1f).toFile(smallFileSavePath);
 tempFile.delete();
 return getResultMap(SUCCESS_CODE,smallerPictureName);
 }else{
 return getResultMap(SUCCESS_CODE,pictureName);
 }
 } catch (Exception e) {
 return getResultMap(ERROR_CODE,"图片上传失败，请稍后重试，或联系管理员");
 }
}

HTML页面

layui.use(['form','layer','upload'], function(){
 var $ = layui.$, form = layui.form, upload = layui.upload, layer = layui.layer;

 // 上传缩略图
 upload.render({
 elem: '.thumbBox',
 data: {typePicture: $('#typePicture').val(), sortPicture: $('#sortPicture').val()},
 url: '/kaptcha/fileUpload',

 before: function(obj){
 //预读本地文件，如果是多文件，则会遍历。(不支持ie8/9)
 layer.load();
 obj.preview(function(index, file, result){
 $('.thumbImg').attr('src', result);
 });
 },
 done: function(res){
 // alert("图片上传成功吗，保存后生效");
 layer.closeAll('loading');
 $("#pictureId").val(res.data);
 $('.thumbBox').css("background","#fff");
 if(res.code != 0){
 alert(res.data);
 }
 }
 });



HTML页面是我目前所用的，可能会有许多不足，多多见谅！
我只是一个小白