别的系统传过来的文件流，转成文件保存

public class FileUtil {

    /**
     * 文件流字符串转文件保存
     * @param base64Code byte[]格式的字符串
     * @param parentPath
     * @param fileName
     * @return
     */
    public String stirngToFile(String base64Code, String parentPath, String fileName) {
        byte[] buffer;
        FileOutputStream out = null;
        try {
            Base64 base64 = new Base64();
            buffer = base64.decode(base64Code);
            //uuid
            fileName = makeFileName(fileName);
            String filePath = parentPath + "/" + fileName;
            out = new FileOutputStream(filePath);
            out.write(buffer);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return fileName;
    }

    /**
     * 创建唯一的文件名uuid
     * @param filename :
     * @return : java.lang.String
     */
    private String makeFileName(String filename) {
        String suffix = "";
        if (StringUtils.isNotBlank(filename)) {
            suffix = "." + filename.substring(filename.lastIndexOf(".") + 1);
        }
        return UUID.randomUUID().toString() + suffix;
    }


}