[java][io]标准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.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
/**
 * 
 * 标准IO重定向
 *
 */
public class IORedirection {

	public static void main(String[] args) {
		PrintStream console = System.out;
		
		BufferedInputStream in = null;
		try {
			in = new BufferedInputStream(new FileInputStream(new File("d:\\a.txt")));
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		PrintStream out = null;
		try {
			out = new PrintStream(new BufferedOutputStream(new FileOutputStream(new File("d:\\a.java").getAbsoluteFile())));
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		System.setIn(in);
		System.setOut(out);
		System.setErr(out);
		
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String s = null;
		try {
			while((s=reader.readLine())!=null){
				System.out.println(s);
			}
			reader.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
		out.close();//调用close清除缓存
	
		System.setOut(console);
		System.out.println("OK");
	}

}