请分析下列程序，写出运行结果。 import java.io.*; public class Main { public static void main(String[] args) throws Exception { final PipedInputStream pis = new PipedInputStream();// 创建PipedInputStream对象 final PipedOutputStream pos = new PipedOutputStream(); // PipedInputStream和PipedOutputStream建立连接，也可写成pos.connect(pis) pis.connect(pos); new Thread(new Runnable() { // 创建一个线程 public void run() { // 将从键盘读取的数据写入管道流 PrintStream ps = new PrintStream(pos); for ( int i=0; i<2; i++ ) { try { System.out.print(Thread.currentThread().getName() + "发送内容："); if ( i == 0 ) { ps.println("Hello world!"); System.out.println("Hello world!"); } else { ps.println("Nice to meet you."); System.out.println("Nice to meet you."); pos.close(); } Thread.sleep(1000); } catch (Exception e) { e.printStackTrace(); } } } }, "发送数据的线程").start(); new Thread(new Runnable() { public void run() { // 下面的代码是从管道流中读出数据，每读一行数据输出一次 BufferedReader br = new BufferedReader(new InputStreamReader( pis)); for ( int i=0; i<2; i++ ) { try { System.out.println(Thread.currentThread().getName() + "收到的内容：" + br.readLine()); } catch (IOException e) { e.printStackTrace(); } } } }, "接收数据的线程").start(); } }