Java# Java对图片进行base64编解码

Posted 2021-09-08 LRcoding

1. 解码BASE64

protected static String generateImage(String imgStr, String path) throws IOException {
    // data:image/jpeg;base64,
    int start = imgStr.indexOf("/");
    int end = imgStr.indexOf(";");
    String ext = "." + imgStr.substring(start + 1, end);
    imgStr = imgStr.substring(imgStr.indexOf(",") + 1);

    // Base64解码
    BASE64Decoder decoder = new BASE64Decoder();
    byte[] b = decoder.decodeBuffer(imgStr);
    for (int i = 0; i < b.length; ++i) {
        if (b[i] < 0) {
            b[i] += 256;
        }
    }

    // 存放位置，文件夹按日期区分
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
    SimpleDateFormat fileSdf = new SimpleDateFormat("yyyyMMddHHmmssSSS");
    String time = sdf.format(new Date());
    String fileName = fileSdf.format(new Date()) + ext;
    File file = new File("C:/file_upload/" + path + time);
    if(!file.exists()){
        file.mkdirs();
    }
    OutputStream out = new FileOutputStream(file + "/" + fileName);
    out.write(b);
    out.flush();
    out.close();
    String photo_address = path + time + "/" + fileName;
    return photo_address;
}

2. BASE64加密

protected String getImageStr(String filePath) {
    InputStream inputStream = null;
    byte[] data = null;
    try {
        inputStream = new FileInputStream(filePath);
        data = new byte[inputStream.available()];
        inputStream.read(data);
        inputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
    // 加密
    BASE64Encoder encoder = new BASE64Encoder();
    return encoder.encode(data);
}