java之PipedWriter和PipedReader

PipedWriter和PipedReader是管道读写，一般就是一个线程写，一个线程读，而且要先写后读。

测试代码：

package com.io;import java.io.Closeable;import java.io.IOException;import java.io.PipedReader;import java.io.PipedWriter;import junit.framework.TestCase;public class TestPipedWriterReader extends TestCase {public void testPipedWriterReader() {PipedWriter pipedWriter = null;PipedReader pipedReader = null;try {pipedWriter = new PipedWriter();pipedReader = new PipedReader();pipedWriter.connect(pipedReader);new Thread(new WriteRunnable(pipedWriter)).start();new Thread(new ReadRunnable(pipedReader)).start();} catch (IOException e) {e.printStackTrace();} finally {close(pipedWriter);close(pipedReader);}}private void close(Closeable closeable) {if (closeable != null) {try {closeable.close();closeable = null;} catch (IOException e) {e.printStackTrace();}}}static class WriteRunnable implements Runnable {private PipedWriter pipedWriter = null;public WriteRunnable(PipedWriter pipedWriter) {this.pipedWriter = pipedWriter;}@Overridepublic void run() {if (pipedWriter == null) {return;}try {pipedWriter.write("hello");} catch (IOException e) {e.printStackTrace();}}}static class ReadRunnable implements Runnable {private PipedReader pipedReader = null;public ReadRunnable(PipedReader pipedReader) {this.pipedReader = pipedReader;}@Overridepublic void run() {if (pipedReader == null) {return;}try {if (pipedReader.ready()) {char[] cbuf = new char[1024];int len = 0;// cyclicBarrier.await();while ((len = pipedReader.read(cbuf)) != -1) {System.out.println(new String(cbuf, 0, len));}}} catch (IOException e) {e.printStackTrace();}}}}