Question

我正在尝试从mp3文件中读取数据，以便以后可以将它们作为十六进制进行操作。假设我在文本编辑器中打开了一个mp3文件，并且看到了字符ÿû²d。转换应以十六进制（表示标题）读取FF FB B2 64。但是，出现在输出文本文件中的十六进制为6E 75 6C 6C，我不知道为什么。

来源：

Java code To convert byte to Hexadecimal

convert audio,mp3 file to string and vice versa

How to check the charset of string in Java?

我的代码：

package mp3ToHex;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.nio.charset.*;

public class mp3ToHex {
  public static void main(String[] args) {
    //directories
    String fileIn = "Some\\Input\\Directory.mp3", fileOut = "Some\\Output\\Directory.txt";
    outputData(fileOut, fileIn);
  }
  @SuppressWarnings("unused")
  public static String readFile(String filename) {
    // variable representing a line of data in the mp3 file
    String line = "";
    try {
      BufferedReader br = new BufferedReader(new FileReader(new File(filename)));

      while (br.readLine() != null) {
        line += br.readLine();

        try {
          if (br == null) {
            // close reader when all data is read
            br.close();
          }

        } catch (FileNotFoundException e) {
          e.getMessage();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    } catch (FileNotFoundException e) {
      e.getMessage();
    } catch (IOException e) {
      e.printStackTrace();
    }
    return line;
  }
  public static void outputData(String outputFile, String inputFile) {
    try {
      // Create file
      FileWriter fileStream = new FileWriter(outputFile);
      BufferedWriter writer = new BufferedWriter(fileStream);
      // Convert string to hexadecimal
      String output = toHex(readFile(inputFile));
      StringBuilder s = new StringBuilder();
      for (int i = 0; i < output.length(); i++) {
        // Format for easier reading
        if (i % 64 == 0) s.append('\n');
        else if (i % 2 == 0) s.append(' ');
        s.append(output.charAt(i));
      }
      // Write to file
      writer.write(s.toString());
      // Close writer
      writer.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  // Converts strings to hexadecimal
  public static String toHex(String arg) throws UnsupportedEncodingException {
    return String.format("%02X", new BigInteger(1, arg.getBytes(charset(arg, new String[] {
      "US-ASCII",
      "ISO-8859-1",
      "UTF-8",
      "UTF-16BE",
      "UTF-16LE",
      "UTF-16"
    }))));
  }
  // Converts strings to different encodings
  public static String convert(String value, String fromEncoding, String toEncoding) throws UnsupportedEncodingException {
    return new String(value.getBytes(fromEncoding), toEncoding);
  }
  // Detects which Charset a string is encoded in by decoding and re-encoding a string. The correct encoding is found if the transformation yields no changes.
  public static String charset(String value, String charsets[]) throws UnsupportedEncodingException {
    String probe = StandardCharsets.UTF_8.name();
    for (String c: charsets) {
      Charset charset = Charset.forName(c);
      if (charset != null) {
        if (value.equals(convert(convert(value, charset.name(), probe), probe, charset.name()))) {
          return c;
        }
      }
    }
    return StandardCharsets.UTF_8.name();
  }
}

Answer 1

在对该程序进行了一些试验之后，我发现用于编码的运行配置更改了输出。通过导航至Run>Run Configurations>[file name]>Common>Encoding，然后从下拉列表中选择ISO-8859-1，可以解决此问题。

来源： https://stackoverflow.com/a/18434549/10589287

更新代码：

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.charset.*;
import java.nio.file.Files;
import java.nio.file.Paths;

public class mp3ToHex {

  public static void main(String[] args) throws IOException {
    //directories
    String fileIn = "Some\\Input\\Directory\\input.mp3",
      fileOut = "Some\\Output\\Directory\\out.txt",
      log = "Some\\Log\\Directory\\log.txt",
      debug = "Some\\Debug\\Directory\\debug.mp3";

    BufferedWriter br = new BufferedWriter(new FileWriter(fileOut)),
      brL = new BufferedWriter(new FileWriter(log)),
      brD = new BufferedWriter(new FileWriter(debug));
    String s = readFile(fileIn, Charset.forName(StandardCharsets.ISO_8859_1.name()));
    brD.write(s);
    byte[] bytes = s.getBytes();
    brL.write(bytesToHex(s.getBytes()));
    StringBuilder binary = new StringBuilder();
    for (byte b: bytes) {
      int val = b;
      for (int i = 0; i < 8; i++) {
        binary.append((val & 128) == 0 ? 0 : 1);
        val <<= 1;
      }
      binary.append(' ');

    }
    br.write(binary + "");
    br.close();
  }
  static String readFile(String path, Charset encoding)
  throws IOException {
    byte[] encoded = Files.readAllBytes(Paths.get(path));
    return new String(encoded, encoding);
  }
  private final static char[] hexArray = "0123456789ABCDEF".toCharArray();
  public static String bytesToHex(byte[] bytes) {
    char[] hexChars = new char[bytes.length * 2];
    for (int j = 0; j < bytes.length; j++) {
      int v = bytes[j] & 0xFF;
      hexChars[j * 2] = hexArray[v >>> 4];
      hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    return new String(hexChars);
  }

}

将mp3文件中的字节表示为十六进制字符串

1 个答案: