java io重定向

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;

public class Redirecting {
public static void main(String[] args) throws Exception {
PrintStream console = System.out;
BufferedInputStream in = new BufferedInputStream(new FileInputStream("./src/zqd/io/Redirecting.java"));
PrintStream out = new PrintStream(new BufferedOutputStream(new FileOutputStream("f:"+File.separator+"java.txt")));
System.setIn(in);
System.setOut(out);
System.setErr(out);
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s = "";
while((s=br.readLine())!=null)
System.out.println(s);
out.close();
//将系统输出恢复到标准输出上
System.setOut(console);
}
}