图片base64报文压缩

1.使用GZIP压缩Base64字符串

    public static String compressBase64(String base64Input) throws IOException {
        // 解码Base64字符串为字节数组
        byte[] data = java.util.Base64.getDecoder().decode(base64Input);
        // 使用GZIP压缩字节数组
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try (GZIPOutputStream gzip = new GZIPOutputStream(bos)) {
            gzip.write(data);
        }
        byte[] compressedData = bos.toByteArray();

        // 将压缩后的字节数组编码为Base64字符串
        return java.util.Base64.getEncoder().encodeToString(compressedData);
    }

2.解压压缩后的Base64字符串

   public static String decompressBase64(String compressedBase64) throws IOException {
        // 解码Base64字符串为压缩后的字节数组
        byte[] compressedData = java.util.Base64.getDecoder().decode(compressedBase64);
        // 解压字节数组
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try (GZIPInputStream gzip = new GZIPInputStream(new java.io.ByteArrayInputStream(compressedData))) {
            byte[] buffer = new byte[1024];
            int len;
            while ((len = gzip.read(buffer)) > 0) {
                bos.write(buffer, 0, len);
            }
        }
        byte[] decompressedData = bos.toByteArray();
        // 将解压后的字节数组重新编码为Base64字符串
        return java.util.Base64.getEncoder().encodeToString(decompressedData);
    }

3.计算报文大小

    /**
     * 获取报文字节数
     *
     * @param str 字符串
     * @return 返回字节数
     */
    public static double calculateStringBytesSize(String str) {
        // 计算字符串的字节数
        int byteCount = str.getBytes(StandardCharsets.UTF_8).length;
        return byteCount;
    }

    /**
     * 将字节数转换为KB并四舍五入保留一位小数
     *
     * @param bytes 字节数
     * @return 转换后的KB值
     */
    public static BigDecimal toKBWithDecimal(double bytes) {
        //return round(bytes /  BYTE_IN_KB, 2);
        //将字节数转换为KB并向上取整
        //return (long) Math.ceil(bytes / BYTE_IN_KB);
        BigDecimal bd = new BigDecimal(bytes);
        BigDecimal divide = bd.divide(new BigDecimal(BYTE_IN_KB), 1, RoundingMode.HALF_UP);
        return divide;
    }

4.验证

    public static void main(String[] args) {
        String body="/9j/4AAQSkZJRgABAQAA........";
        String compressed = compressBase64(body);
        System.out.println("compressed 压缩后的字符串长度：" + compressed.length());
　　　　 System.out.println("compressed:kb:" + toKBWithDecimal(calculateStringBytesSize(compressed)));
        String decompressed = decompressBase64(compressed);
        System.out.println("decompressed解压缩后的字符串长度：" + decompressed.length());
　　　　 System.out.println("compressed:kb:" + toKBWithDecimal(calculateStringBytesSize(decompressed)));		
        System.out.println("decompressed base64验证结果: " + body.equals(decompressed));
    }