java 从blob类型得到图片文件

 
    public static String getImageForBlob(byte[] bytes,String name) {

        // 读取文件的前几个字节来判断图片格式
        byte[] b = new byte[4];
        for (int i = 0; i < b.length; i++) {
            b[i] = bytes[i];
        }
        String type = HexUtil.encodeHexStr(b).toUpperCase();;
        if (type.contains("FFD8FF")) {
            type = "JPG";
        } else if (type.contains("89504E47")) {
            type = "png";
        } else if (type.contains("47494638")) {
            type = "GIF";
        } else if (type.contains("424D")) {
            type = "BMP";
        }else{
            type = "jpeg";
        }

        // 设置文件地址
        String destDir = "d:/pic";
        String path = StrUtil.format("{}/{}."+type, destDir,name );

        // 将byte[]转换为输入流写入文件
        InputStream sbs = new ByteArrayInputStream(bytes);
        FileUtil.writeFromStream(sbs, path);

        return urlPath;

    }