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...
        }
    }
}