/**
	 * base64转inputStream
	 * @param base64string
	 * @return
	 */
	private static InputStream BaseToInputStream(String base64string){
	    ByteArrayInputStream stream = null;
		try {
		    BASE64Decoder decoder = new BASE64Decoder();
		    byte[] bytes1 = decoder.decodeBuffer(base64string);
		    stream = new ByteArrayInputStream(bytes1);
		} catch (Exception e) {
		// TODO: handle exception
		}
	        return stream;
	    }

 文件上传之MultipartFile(图片)转base64

BASE64位转图片类型 JAVA