Question

我正在使用FileOutputStream编写文件，我注意到hex似乎包含终止0x0a。以下是文件的输出：

0000000: d100 0b00 0000 4865 6c6c 6f20 776f 726c  ......Hello worl
0000010: 6429 0043 0500 0000 7072 696e 740a       d).C....print.

(Note hex code comes from vim on Osx Yosimite x64)

请注意，文件以0x0a结尾。这是一个linux的东西（比如某种EOF字符）还是这个java / FileOutputStream附加了字符？

编辑：代码

public class FileImageOpcodeRenderer implements OpCodeRenderer, AutoCloseable {
  private final FileOutputStream stream;
  private final Iterable<OpCode> opcodes;
  private final List<Byte> data = new ArrayList<>();

  public FileImageOpcodeRenderer(Iterable<OpCode> opcodes, String path) {
    this.opcodes = opcodes;
    try {
      this.stream = new FileOutputStream(path);
    } catch (IOException ex) {
      ex.printStackTrace();

      throw new CompilerException("Unable to open output file");
    }
  }

  public void save() throws Exception {
    List<Byte> renderedContent = renderOpCodes();
    byte[] content = toArray(renderedContent);
    stream.write(content, 0, content.length);
  }

  private List<Byte> renderOpCodes() {
    for (OpCode opCode : opcodes) {
      writeInt8(null, opCode.opNumber());
      opCode.render(this);
    }

    return this.data;
  }

  private byte[] toArray(List<Byte> data) {
    byte[] content = new byte[data.size()];

    for (int index = 0; index < data.size(); index++) {
      content[index] = data.get(index);
    }

    return content;
  }

  @Override
  public void writeInt8(String label, int value) {
    data.add((byte)value);
  }

  @Override
  public void writeInt16(String label, int value) {
    writeInt8(null, (byte)(value & 0xFF));
    writeInt8(null, (byte)((value >> 8) & 0xFF));
  }

  @Override
  public void writeInt32(String label, int value) {
    writeInt8(null, (byte)(value & 0xFF));
    writeInt8(null, (byte)((value >> 8) & 0xFF));
    writeInt8(null, (byte)((value >> 16) & 0xFF));
    writeInt8(null, (byte)((value >> 24) & 0xFF));
  }

  @Override
  public void writeInt64(String label, long value) {
    writeInt8(null, (byte)(value & 0xFF));
    writeInt8(null, (byte)((value >> 8) & 0xFF));
    writeInt8(null, (byte)((value >> 16) & 0xFF));
    writeInt8(null, (byte)((value >> 24) & 0xFF));
    writeInt8(null, (byte)((value >> 32) & 0xFF));
    writeInt8(null, (byte)((value >> 40) & 0xFF));
    writeInt8(null, (byte)((value >> 48) & 0xFF));
    writeInt8(null, (byte)((value >> 56) & 0xFF));
  }

  @Override
  public void writeString(String label, String value) {
    writeInt32(null, value.length());
    for (byte letter : value.getBytes()) {
      System.out.println((int)letter);
      writeInt8(null, letter);
    }
  }

  @Override
  public void close() throws Exception {
    stream.close();
  }
 }

我甚至查看save中的原始字节，它以0x74结尾，而不是0x0a。

更新：Moar Code：

所以我只是编写了这段代码来加载c ++中的文件：

int main() {
    int fd = open("/Users/sircodesalot/Desktop/image.vbaj", O_RDONLY);

    char buffer[256] { };
    int amout = read(fd, buffer, 256);

    cout << amout << endl;

    for (int index = 0; index != 256; ++index) {
        if (index > 0 && (index % 10 == 0)) cout << endl;
        cout << hex << (int)buffer[index] << " ";
    }

    close(fd);
}

输出：

29
ffffffd1 0 b 0 0 0 48 65 6c 6c 
6f 20 77 6f 72 6c 64 29 0 43 
5 0 0 0 70 72 69 6e 74 0 
0 0 0 0 0 0 0 0 0 0
... (rest of the 256 byte buffer)

看看马，没有0xa？这有什么用？也许有些Linux惯例？

Answer 1

问题可能就在这里：

@Override
public void writeString(String label, String value) {
  writeInt32(null, value.length());
  for (byte letter : value.getBytes()) {
      System.out.println((int)letter);
      writeInt8(null, letter);
  }
}

您正在以字符编写长度，但随后继续从getBytes（）写入字节。 getBytes（）使用String的平台编码，取决于编码是什么，getBytes（）可以返回任何。

尝试明确指定编码，例如value.getBytes(Charset.forName("ISO-8859-1"));

编辑：还要确保输出的字符串确实包含您认为包含的内容。

为什么Java / Linux将0xa附加到文件末尾？

1 个答案: