java线程间通信之通过管道进行通信

管道流PipeStream是一种特殊的流，用于在不同线程间直接传送数据，而不需要借助临时文件之类的东西。

jdk中提供了四个类来使线程间可以通信：

1）PipedInputStream和PipedOutputStream

2）PipedReader和PipedWriter

先看看字节流的示例：

public class ReadData {
    
    public void readMethod(PipedInputStream in) throws IOException{
        System.out.println("begin read...");
        byte[] b = new byte[20];
        int readLength = in.read(b);
        while (readLength != -1) {
            String newData = new String(b, 0, readLength);
            System.out.println("read:"+newData);
            readLength = in.read(b);
        }
        in.close();
        System.out.println("end read...");
    }

}

public class WriteData {

    public void writeMethod(PipedOutputStream out) throws IOException{
        System.out.println("begin write...");
        for (int i = 0; i < 10; i++) {
            out.write((""+i).getBytes());
            System.out.println("write:"+i);
        }
        out.close();
        System.out.println("end write...");
    }
}

public class ThreadRead extends Thread {
    
    private ReadData readData;
    private PipedInputStream in;

    public ThreadRead(ReadData readData, PipedInputStream in) {
        this.readData = readData;
        this.in = in;
    }
    
    @Override
    public void run() {
        try {
            readData.readMethod(in);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class ThreadWrite extends Thread {
    
    private WriteData writeData;
    private PipedOutputStream out;
    
    public ThreadWrite(WriteData writeData, PipedOutputStream out) {
        this.writeData = writeData;
        this.out = out;
    }

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

public class Run {
    public static void main(String[] args) throws IOException, InterruptedException {
        WriteData writeData = new WriteData();
        ReadData readData = new ReadData();
        
        PipedOutputStream out = new PipedOutputStream();
        PipedInputStream in = new PipedInputStream();
        
        in.connect(out);
        
        new ThreadWrite(writeData, out).start();
        Thread.sleep(2000);
        new ThreadRead(readData, in).start();
    }
}

再看看字符流示例：

public class ReadData {
    
    public void readMethod(PipedReader reader) throws IOException{
        System.out.println("begin read...");
        char[] c = new char[20];
        int readLength = reader.read(c);
        while (readLength != -1) {
            String newData = new String(c, 0, readLength);
            System.out.println("read:"+newData);
            readLength = reader.read(c);
        }
        reader.close();
        System.out.println("end read...");
    }

}

public class WriteData {

    public void writeMethod(PipedWriter writer) throws IOException{
        System.out.println("begin write...");
        for (int i = 0; i < 10; i++) {
            writer.write((""+i));
            System.out.println("write:"+i);
        }
        writer.close();
        System.out.println("end write...");
    }
}

public class ThreadRead extends Thread {
    
    private ReadData readData;
    private PipedReader reader;

    public ThreadRead(ReadData readData, PipedReader reader) {
        this.readData = readData;
        this.reader = reader;
    }
    
    @Override
    public void run() {
        try {
            readData.readMethod(reader);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class ThreadWrite extends Thread {
    
    private WriteData writeData;
    private PipedWriter writer;
    
    public ThreadWrite(WriteData writeData, PipedWriter writer) {
        this.writeData = writeData;
        this.writer = writer;
    }

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

public class Run {
    public static void main(String[] args) throws IOException, InterruptedException {
        WriteData writeData = new WriteData();
        ReadData readData = new ReadData();
        
        PipedWriter writer = new PipedWriter();
        PipedReader reader = new PipedReader();
        
        writer.connect(reader);
        
        new ThreadWrite(writeData, writer).start();
        Thread.sleep(2000);
        new ThreadRead(readData, reader).start();
    }
}