public static void main(String args[]) {
try {
String fname = "d:\\q.txt";
String mode;
// mode = "r";//r : file must exist
mode = "rw"; // rw : file will be created or opened
// open the file
RandomAccessFile raf = new RandomAccessFile(fname, mode);
/*
//seek and write demo
raf.seek(10);//position file r/w pointer at index 10 wrt BOF
//a seek beyond file size causes file to grow upto the seek value
raf.write(65);//raf.write('A');
*/
// r/w java datatypes
int i1, i2;
float f1, f2;
char c1, c2;
String s1, s2;
i1 = -10;
f1 = 1234.5678F;
c1 = 'q';
s1 = "hello files";
raf.seek(0); // reach BOF
raf.writeInt(i1);
raf.writeFloat(f1);
raf.writeChar(c1);
raf.writeUTF(s1);
raf.seek(0); // reach BOF
i2 = raf.readInt();
f2 = raf.readFloat();
c2 = raf.readChar();
s2 = raf.readUTF();
System.out.println(i2);
System.out.println(f2);
System.out.println(c2);
System.out.println(s2);
// close the file
raf.close();
} catch (IOException ex) {
System.out.println(ex); // ex converts into ex.toString()
}
} // main
public static void main(String args[]) {
RandomAccessFile classe = null;
Scanner entrada = new Scanner(System.in);
Aluno b = new Aluno();
boolean achou = false;
float media;
try {
classe = new RandomAccessFile("c:\\alunos.dat", "rw");
achou = false;
while (true) {
b.numero = classe.readInt();
b.nome = classe.readUTF();
b.curso = classe.readUTF();
b.nota1 = classe.readFloat();
b.nota2 = classe.readFloat();
media = (float) ((b.nota1 + b.nota2) / 2);
if (media >= 7) {
System.out.print("\nNome: " + b.nome);
System.out.print("\nCurso: " + b.curso);
System.out.print("\nNota1: " + b.nota1);
System.out.print("\nNota2: " + b.nota2);
System.out.print("\nMedia: " + media + "\n");
}
}
} // fim try
catch (EOFException e) {
try {
classe.close();
} // fim try
catch (IOException e2) {
System.out.println("\nErro de I/O");
}
} // fimn catch (EOFException e)
catch (IOException e) {
System.out.println("Erro na criacao o arquivo");
}
} // fim main
public My_Room_AC_db(String name) {
y = new ArrayList<String>();
try {
raf = new RandomAccessFile("ac_db.dat", "r");
String arr2[] = name.split("#");
while (true) {
String rec = raf.readUTF();
String arr[] = rec.split("#");
if (arr[0].equals(arr2[0])) {
y.add(name);
} else {
y.add(rec);
}
}
} catch (Exception ep) {
} finally {
try {
// if(raf!=null)
raf.close();
File f = new File("ac_db.dat", "r");
f.delete();
} catch (Exception ex) {
}
}
raf = null;
try {
raf = new RandomAccessFile("ac_db.dat", "rw");
for (String ss : y) {
raf.writeUTF(ss);
}
} catch (Exception ef) {
} finally {
try {
raf.close();
} catch (Exception ex) {
}
}
}
public T readObj(String fileName) {
RandomAccessFile file = null;
T retObj = null;
if (!configDirExists(fileName)) {
return null;
}
try {
file = new RandomAccessFile(fileName, "rw");
if (debug) {
System.out.printf("ConfigLoader reading:%s\n", fileName);
}
retObj = (T) xstream.fromXML(file.readUTF());
} catch (IOException ex) {
System.err.printf(
"Warning: failed to read config:%s : %s -- %s\n",
configPathToFile, fileName, getPathToConfigDir());
return null;
} finally {
try {
if (file != null) {
file.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
if (retObj != null && retObj instanceof ConfPortfolio) {
ConfPortfolio config = (ConfPortfolio) retObj;
if (config.useCurentDayAsEndingDate) {
config.inputEndingDate = new DateTime();
}
}
return retObj;
}
private String readString(long strOffset) throws IOException {
stringFile.seek(strOffset);
return stringFile.readUTF();
}