java-初识输入输出重定向以及简单输入流输出

 1 package com.etc;
 2 
 3 import java.io.BufferedInputStream;
 4 import java.io.BufferedOutputStream;
 5 import java.io.FileInputStream;
 6 import java.io.FileNotFoundException;
 7 import java.io.FileOutputStream;
 8 import java.io.InputStream;
 9 import java.io.PrintStream;
10 import java.util.Scanner;
11 
12 /*
13  * 对输入输出流进行打印
14  * System.in
15  * System.out
16  * System.err
17  * 输入输出重定向:
18  * System.setIn(InputStream in)
19  * System.setOut(PrintStream out)
20  * System.setErr(PrintStream err);
21  * 回控制台:
22  * FileDiscriptor.in
23  * FileDiscriptor.out
24  * FileDiscriptor.err
25  */
26 public class OverideSystem {
27 
28     public static void main(String[] args) throws FileNotFoundException {
29         Overide();
30         System.out.println("I like codes very much!");
31         testPrintStream();    
32     }
33     //重定向方法实现
34     public static void Overide() throws FileNotFoundException {
35         //重定向输入方式及自动更新
36         System.setOut(new PrintStream(new BufferedOutputStream(new FileOutputStream("E:/test.txt")),true));
37     }
38 
39     public static void testPrintStream() throws FileNotFoundException {
40         //通过文件输入流放入系统的输入，然后再通过Scanner函数将输入结果打印出来
41         InputStream in=System.in;
42         in=new BufferedInputStream(new FileInputStream("E:/test.txt"));
43         Scanner sc=new Scanner(in);
44         System.out.println("输出结果:");
45         System.out.println(sc.nextLine());
46 
47     }
48 }