Java IO.pdf - Nguyen Dang Binh

public class RandomInputStream extends InputStream {
}
private transient Random generator = new Random();
public int read() {
}
int result = generator.nextInt() % 256;
if (result < 0) result = -result;
return result;
Java I/O
public int read(byte[] data, int offset, int length) throws IOException {
}
byte[] temp = new byte[length];
generator.nextBytes(temp);
System.arraycopy(temp, 0, data, offset, length);
return length;
public int read(byte[] data) throws IOException {
}
generator.nextBytes(data);
return data.length;
public long skip(long bytesToSkip) throws IOException {
}
// It's all random so skipping has no effect.
return bytesToSkip;
The no-argument read() method returns a random int in the range of an unsigned byte (0 to
255). The other two read() methods fill a specified part of an array with random bytes. They
return the number of bytes read (in this case the number of bytes created).
3.9 An Efficient Stream Copier
As a useful example of both input and output streams, in Example 3.3 I'll present a
StreamCopier class that copies data between two streams as quickly as possible. (I'll reuse
this class in later chapters.) This method reads from the input stream and writes onto the
output stream until the input stream is exhausted. A 256-byte buffer is used to try to make the
reads efficient. A main() method provides a simple test for this class by reading from
System.in and copying to System.out.
Example 3.3. The StreamCopier Class
package com.macfaq.io;
import java.io.*;
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