java - 文件写入 : String to Bytes

Question

我想将字符串/字符数据作为字节写入文件中。我希望这种转换在 IO.* 类内部发生。我不想对字符串使用 getBytes() 方法。

我尝试了以下两个程序，但都将数据写入 Character 。当我在记事本中打开文件时，我可以读取这些字符。如何将数据存储为字节？

     import IO.FileWrite;

         import java.io.*;

        public class CharToChar {

private final String data;

public CharToChar(String data){
    this.data = data;
}

public static void main(String[] args) throws IOException {
    final CharToChar charToChar = new CharToChar("I am Manish");
    charToChar.write();
}

private void write() throws IOException {
    final File file = new File("CharToChar.txt");
    final FileWriter fileWriter = new FileWriter(file);
    final BufferedWriter bufferdWriter = new BufferedWriter(fileWriter);
    bufferdWriter.write(this.data);
    bufferdWriter.close();

}
  }


     import java.io.DataOutputStream;
     import java.io.FileOutputStream;
       import java.io.IOException;

       public class WriteStringAsBytesToFile {

public static void main(String[] args) {

    String strFilePath = "WriteStringAsBytes.txt";

    try
    {
        //create FileOutputStream object
        FileOutputStream fos = new FileOutputStream(strFilePath);

  /*
   * To create DataOutputStream object from FileOutputStream use,
   * DataOutputStream(OutputStream os) constructor.
   *
   */

        DataOutputStream dos = new DataOutputStream(fos);

        String str = "This string will be written to file as sequence of bytes!";

   /*
    * To write a string as a sequence of bytes to a file, use
    * void writeBytes(String str) method of Java DataOutputStream class.
    *
    * This method writes string as a sequence of bytes to underlying output
    * stream (Each character's high eight bits are discarded first).
    */

        dos.writeBytes(str);

    /*
     * To close DataOutputStream use,
     * void close() method.
     *
     */

        dos.close();

    }
    catch (IOException e)
    {
        System.out.println("IOException : " + e);
    }

}
   }

注意 -> JAVA 文档说 输出流写入器OutputStreamWriter 是从字符流到字节流的桥梁: * 写入它的字符使用指定的编码成字节。

Answer 1

我认为您对以字节/字符形式编写的概念是错误的。字符，只是字节数据的表示。这种表示是根据 Character Encoding 决定的类型。看下面的代码:

OutputStream os = new FileOutputStream(filePath);
    os.write("This is byte date".getBytes("UTF-8"));
    os.close();

如果您在运行上述代码段后打开文件，您会注意到文件中有相同的字符串。您的文件始终包含以字节为单位的数据。这些字节由您的文本编辑器读取并根据其默认字符编码进行编码，通常是 UTF-8 但并非总是如此。