Java IO.pdf - Nguyen Dang Binh

}
}
try {
// So that the buffer doesn't have to be resized,
// we calculate in advance the size of the necessary byte array.
ByteArrayOutputStream bout = new ByteArrayOutputStream(howMany*4);
DataOutputStream dout = new DataOutputStream(bout);
// First two Fibonacci numbers must be given
// to start the process.
int f1 = 1;
int f2 = 1;
dout.writeInt(f1);
dout.writeInt(f2);
// Now calculate the rest.
for (int i = 2; i < howMany; i++) {
int temp = f2;
f2 = f2 + f1;
f1 = temp;
dout.writeInt(f2);
}
FileOutputStream fout = new FileOutputStream(outputFile);
fout.write(bout.toByteArray());
fout.flush();
fout.close();
}
catch (IOException e) { System.err.println(e); }
Java I/O
You can use the FileDumper3 program from the last chapter with the -i option to view the
output. For example:
% java FibonacciFile fibonacci.dat 10
% java FileDumper3 -i fibonacci.dat
1
1
2
3
5
8
13
21
34
55
8.3 Communicating Between Threads with Piped Streams
The java.io.PipedInputStream class and java.io.PipedOutputStream class provide a
convenient means to move streaming data from one thread to another. Output from one thread
becomes input for the other thread, as shown in Figure 8.1
135