java需要关注的知识点---标准I0流

System.in

public class SystemInTest {
	public static void main(String[] args) throws IOException {
		BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
		String s;
		while((s = stdin.readLine())!= null && s.length()!= 0) {
			System.out.println(s);
		}
	}
}

将System.out转换成PrintWriter:

public class SystemOutTest {
	public static void main(String[] args) {
		PrintWriter out = new PrintWriter(System.out,true);
		out.println("Hello,World");
	}
}

标准I0的重定向：

public class Redirecting {
	public static void main(String[] args) throws IOException, InterruptedException {
		PrintStream console = System.out;
		BufferedInputStream in = new BufferedInputStream(new FileInputStream("D:\\RSA75WP\\test\\src\\com\\io\\Redirecting.java"));
		PrintStream out = new PrintStream(new BufferedOutputStream(new FileOutputStream("test.out")));
		System.setIn(in);
		System.setOut(out);
		System.setErr(out);
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		Thread.sleep(4000);
		String s;
		while((s = br.readLine())!= null) {
			System.out.println(s);
		}
		out.close();
		System.setOut(console);
	}
}