将Java编码文件转换为Base64字符串以与其他编码的字符串匹配

问题描述：

private static String encodeFileToBase64Binary(String fileName)
        throws IOException {

    File file = new File(fileName);
    byte[] bytes = loadFile(file);
    byte[] encoded = Base64.encodeBase64(bytes);
    String encodedString = new String(encoded,StandardCharsets.US_ASCII);

    return encodedString;
}
private static byte[] loadFile(File file) throws IOException {
    InputStream is = new FileInputStream(file);

    long length = file.length();
    if (length > Integer.MAX_VALUE) {
        // File is too large
    }
    byte[] bytes = new byte[(int)length];

    int offset = 0;
    int numRead = 0;
    while (offset < bytes.length
           && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
        offset += numRead;
    }

    if (offset < bytes.length) {
        throw new IOException("Could not completely read file "+file.getName());
    }

    is.close();
    return bytes;
}

//获取编码字符串

String encoded=encodeFileToBase64Binary("file.fmr");

//编码的字符串是:

Rk1SACAyMAAAAAFiAAABQAHgAMUAxQEAAABGNkDZADP/SEC8AD6CSECqAEcGSED+AFJtO0CgAGCKZEC6AGuFZEDgAHz1ZECzAI6HZEENAJluNEBWAJ4ZZEB1AKkTZEECALbuZEA/ALqfSECCALySSECxAMP/ZECIAMURVUAXAN2jGkCnAOD8ZEAoAOWlZEBnAOyhLkCyAP/tZECHAQMSGkD8AQTdZECfASKFGkCHASUaGkA1ASy6ZEDAAS3JZEDPAS7NZEAnATG4ZEDxATzOZEBOAUPLZEBzAVbuGkCAAWF8NEDTAWsxLkDnAXa0LkC/AX2nLkC0AYojIEBMAYvkSEDJAa0fT0CsAbwVIIDqANTsZIDIAPfnZICbAQKHO4D5AR/XZIBlASS7IIEoASbYO4CsAUetLoDvAVXSZIDaAVvDO4EHAWrLZICsAX2fNIDnAYEwNIDQAZKnT4BfAZxtZAAA

//使用其他来源的文件中的编码字符串.

//encoded string from file using some other source.

Rk1SACAyMAAAAAFiAAABQAHgAMUAxQEAAABGNkCLACELSEDAADYDZEEYAGFxO0DGAGJ9SEC1AGkCSEA6AHWYVUDJAHp5ZEBEAHwVZECVAJgIZEEaALHrZEB4ALuOZEELAMFqZEEzAM/sNEDRANvwZEBkAN0VZECcAOIAZEEwAOjnLkEvAPXlO0CnAP71ZEB7AQYRNEBdAQ0eZED8ARDhZEDXASXcZECZAS3uGkBoAT4eO0AUAUMxSEA7AUYqZEDxAUnSZECmAVNDO0EIAXDHSEDYAXW7ZEEUAXXKSEEGAYY8IEEhAYrDNEDfAZ81ZEDQAcGqLoEBAC/7O4EGAE7zVYB+AP2QSICEARuLZIBnATUfO4D/ATXaZIDEATjSZIDRATrVZICnATvSNIBTATwnZIARAV1LGoB1AV2oO4CrAV68SIDnAWHGZIB+AWauNICVAX0ySICNAYytO4CJAZorSAAA

当我尝试同时匹配两个编码字符串时，我遇到了不匹配的情况. 请建议将文件编码为base64的方法，以匹配从其他来源找到的编码字符串. 我已经尝试使用StandardCharsets.UTF_8和StandardCharsets.US_ASCII.

When i am trying to match both the encoded string , i am getting a missmatch. please suggest method for encode file to base64 to match encoded string found from other source. i have tried with StandardCharsets.UTF_8 and StandardCharsets.US_ASCII.

答

您已经在使用apache commons-codec，因此，我建议添加commons-io来读取文件.这样，您可以删除loadFile()方法，而只需:

You already using apache commons-codec so I recommend adding commons-io for reading the file. That way you can remove your loadFile() method and just have:

private static String encodeFileToBase64Binary(String fileName) throws IOException {
    File file = new File(fileName);
    byte[] encoded = Base64.encodeBase64(FileUtils.readFileToByteArray(file));
    return new String(encoded, StandardCharsets.US_ASCII);
}

将Java编码文件转换为Base64字符串以与其他编码的字符串匹配

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