Java重定向IO

import java.io.*;
import java.util.*;

public class Main {
public static void main(String[] args) throws IOException {
System.setIn(new BufferedInputStream(new FileInputStream("ride.in")));
System.setOut(new PrintStream(new FileOutputStream("ride.out")));

Scanner cin = new Scanner(System.in);
while(cin.hasNext()){
// do staff...
}
}
}