java web service 寫入圖片到web/img/

獲取本類service路徑，而後字符串截取和拼接
  String classpath= this.getClass().getResource("/").getPath();

            String path = classpath.substring(0,classpath.length() - "WEB-INF/classes/".length());

            System.out.println(path);

            Path file=new File(path+"assets/img/code.png").toPath();