Java使用PipedStream管道流通信

多线程使用PipedStream 通讯

Java 提供了四个相关的管道流，我们可以使用其在多线程进行数据传递,其分别是

类名	作用	备注
PipedInputStream	字节管道输入流	字节流
PipedOutputStream	字节管道输出流	字节流
PipedReader	字符管道读取	字符流
PipedWriter	字符管道写入	字符流

其分为两类：字节流和字符流，基本步骤为：线程A写入数据到输出流/写入，线程B读取数据从输入流/字符读取,从而实现线程通讯，下面我们先看下基于字节流的实现方法.

写数据到输出流

package com.zhoutao.demo.thread.piped;

import java.io.IOException;
import java.io.PipedOutputStream;
import java.util.concurrent.TimeUnit;

public class WriteData {

  private int count = 0;

  public void writeMethod(PipedOutputStream pipedOutputStream) throws InterruptedException, IOException {
    while (true) {
        // 每隔1s向输出流写入数字字符串
      pipedOutputStream.write(String.valueOf(count++).getBytes());
      TimeUnit.SECONDS.sleep(1);
    }
  }
}

读数据从输入流

package com.zhoutao.demo.thread.piped;

import java.io.IOException;
import java.io.PipedInputStream;

public class ReadData {

  public void readMethod(PipedInputStream inputStream) throws IOException {
    byte[] bytes = new byte[20];
    int read;
      // 当流中不存在数据时候，read方法会进入阻塞状态
    while ((read = inputStream.read(bytes)) != -1) {
      String newData = new String(bytes, 0, read);
      System.out.println("Get Data = " + newData);
    }
  }
}

启动测试

package com.zhoutao.demo.thread.piped;

import java.io.IOException;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;

public class PipesStreamDemo {

  public static void main(String[] args) throws IOException {
    // 创建读写对象
    WriteData writeData = new WriteData();
    ReadData readData = new ReadData();

    // 创建管道输入输出流
    PipedInputStream pipedInputStream = new PipedInputStream();
    PipedOutputStream pipedOutputStream = new PipedOutputStream();

    // 重点:连接管道流
    pipedOutputStream.connect(pipedInputStream);

    // 创建对应的线程并启动
    ThreadRead threadRead = new ThreadRead(readData, pipedInputStream);
    ThreadWrite threadWrite = new ThreadWrite(writeData, pipedOutputStream);
    threadRead.start();
    threadWrite.start();
    
    // 观察控制台输出的数据
  }

  static class ThreadRead extends Thread {
    private ReadData readData;

    private PipedInputStream inputStream;

    public ThreadRead(ReadData readData, PipedInputStream inputStream) {
      this.readData = readData;
      this.inputStream = inputStream;
    }

    @Override
    public void run() {
      try {
        readData.readMethod(inputStream);
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }

  static class ThreadWrite extends Thread {
    private WriteData writeData;

    private PipedOutputStream pipedOutputStream;

    public ThreadWrite(WriteData writeData, PipedOutputStream pipedOutputStream) {
      this.writeData = writeData;
      this.pipedOutputStream = pipedOutputStream;
    }

    @Override
    public void run() {
      try {
        writeData.writeMethod(pipedOutputStream);
      } catch (InterruptedException e) {
        e.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
}

测试数据

Get Data = 0
Get Data = 1
Get Data = 2
Get Data = 3
Get Data = 4
Get Data = 5
Get Data = 6
Get Data = 7