Java -如何通过字节读取.dat文件开发者社区

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Info about Fields 
    FieldCode: Word;   //2 bytes
    FieldName: ShortString;   //1 byte
Info in Field 
    FieldCode: Word;  //2 bytes
    FieldText: String[255];  //1 byte
    DateTime = double

    package binarios5;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class Main5 
    public static void main(String[] args) throws FileNotFoundException, IOException 
            Path path = Paths.get("C:\\\\Dev-Pas\\\\EXAMEN2.dat");
            System.out.println("File open");
            byte[] bytes = Files.readAllBytes(path);
            ByteBuffer buffer = ByteBuffer.wrap(bytes);
            buffer.order(ByteOrder.BIG_ENDIAN);
            short serial = buffer.getShort();
            System.out.println("----[CONTENIDO DEL ARCHIVO]--------------------");
            System.out.println("Nro. de Serie: " + serial);
            int largoCadena = buffer.get();//Bytes 1 int Longitud de la cadena
            //System.out.println("largoCadena: " + largoCadena);//33
            byte[] bytesChar = new byte[largoCadena];//CString
            buffer.get(bytesChar);
            String nombre = new String(bytesChar, StandardCharsets.ISO_8859_1);
            System.out.println("Nombre: " + nombre);
            short date = buffer.getShort();//FALTA DECODIFICAR FECHA
            System.out.println("Fecha sin procesar. "+date);//FALTA DECODIFICAR FECHA
            short cantCampos = buffer.getShort(); //cantidad de campos que tienen los registros
            System.out.println("Cantidad de Campos Customizados: "+cantCampos);//debe decir 4
            int[] codCampo = new int[cantCampos];
            String[] nombreCampo = new String[10];
            for (int i = 0; i < cantCampos; i++) //leer RegType segun la cantidad de campos
                codCampo[i] = buffer.getShort();//Bytes 2 codigo del campo
                int largoCadena2 = buffer.get();//Bytes 1 int Longitud de la cadena
                byte[] bytesChar2 = new byte[largoCadena2];
                buffer.get(bytesChar2);
                nombreCampo[i] = new String(bytesChar2, StandardCharsets.ISO_8859_1);
            for (int i = 0; i < cantCampos; i++)//mostrar codigos y campos
                System.out.println("Campo [codigo: " + codCampo[i] + ", descripcion: " + nombreCampo[i] + "]");
            short cantRegistros = buffer.getShort();//cantidad de registros total
            System.out.println("Cantidad de Registros: "+cantRegistros);
            System.out.println("-----------------------");//OK
            String[] contenidoCampo = new String[10];
            for (int i = 0; i < cantRegistros; i++) //leyendo RegData 5 veces
                short cantCamposCompletos = buffer.getShort();
                for (int j = 0; j < cantCamposCompletos; j++)
                    short codCampoInterno = buffer.getShort();
                    int largoCadena3 = buffer.get();
                    byte[] bytesChar3 = new byte[largoCadena3];
                    buffer.get(bytesChar3);
                    contenidoCampo[j] = new String(bytesChar3, StandardCharsets.ISO_8859_1);
                    System.out.println(nombreCampo[j]+": "+contenidoCampo[j]); 
                System.out.println("-----------------------");
            System.out.println("----[FIN CONTENIDO DEL ARCHIVO]-----------------");
        catch (IOException e)
            System.out.println("File I/O error!");
}

BufferedInputStream in = new BufferedInputStream(new FileInputStream(...));

Path path = Paths.get("C:/xxx/yyy.dat");
byte[] bytes = Files.readAllBytes(path);
ByteBuffer buffer = ByteBuffer.wrap(bytes);
//buffer.order(ByteOrder.LITTLE_ENDIAN); // So short is read as LSB,MSB

// Header
short serial = buffer.getShort();
byte[] fileNameB = new byte[255];
buffer.get(fileNameB);
// If 0 terminated asciz string:
int len = fileNameB.length;
for (int i = 0; i < fileNameB.length; ++i) {
    if (fileNameB[i] == 0) {
        len = i;
        break;
String fileName = new String(fileNameB, 0, len, StandardCharsets.ISO_8859_1);
short date = buffer.getShort();
short fieldNumbers = buffer.getShort();
short numbersOfRecords = buffer.getShort();
for (int fieldI = 0; fieldI < fieldNumber; ++fieldI) {
    // Info about Fields 
    short fieldCode = buffer.getShort();
    //byte fieldName: ShortString;   //1 byte
}

DateTime = double

String getPascalString(ByteBuffer buffer) {
    int length = buffer.get() & 0xFF;
    byte[] bytes = new byte[length];

问 Java -如何通过字节读取.dat文件

回答 2

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