Java nio 的线程通信机制线程通信Pipe

news2024/11/27 6:17:25

Java的Pipe是一种新的线程通信机制，传统的线程通信可以是通过共享内存的方式，socket等方式，而Pipe是通过Java NIO 通信的方式实现共享内存，优点类似于go语言的管道

先上代码

    public static void main(String[] args) throws IOException {
        Pipe open = Pipe.open();
        Pipe.SinkChannel sinkChannel = open.sink();
        ByteBuffer byteBuffer = ByteBuffer.allocateDirect(32);
        byteBuffer.clear();
        byteBuffer.put("你好 pipe".getBytes());
        byteBuffer.flip();
        sinkChannel.write(byteBuffer);
        Pipe.SourceChannel source = open.source();
        ByteBuffer byteBuffer1 = ByteBuffer.allocateDirect(32);
        source.read(byteBuffer1);

    }

这段代码我没有开启多线程读写

只讲底层实现

首先 SinkChannel 和 SourceChannel 是两个内部类这个两个类都有一个SocketChannel

但是SinkChannel只提供了写方法 SourceChannel提供了读方法，相当于是对原始SocketChannel的一个封装，使其达到了一个SocketChannel 只能读一个SocketChannel 只能写的效果。所以就可以做到线程间通信

  ServerSocketChannel var1 = null;
                SocketChannel var2 = null;
                SocketChannel var3 = null;

                try {
                    ByteBuffer var4 = ByteBuffer.allocate(16);
                    ByteBuffer var5 = ByteBuffer.allocate(16);
                    InetAddress var6 = InetAddress.getByName("127.0.0.1");

                    assert var6.isLoopbackAddress();

                    InetSocketAddress var7 = null;

                    while(true) {
                        if (var1 == null || !var1.isOpen()) {
                            var1 = ServerSocketChannel.open();
                            var1.socket().bind(new InetSocketAddress(var6, 0));
                            var7 = new InetSocketAddress(var6, var1.socket().getLocalPort());
                        }

                        var2 = SocketChannel.open(var7);
                        PipeImpl.RANDOM_NUMBER_GENERATOR.nextBytes(var4.array());

                        do {
                            var2.write(var4);
                        } while(var4.hasRemaining());

                        var4.rewind();
                        var3 = var1.accept();

                        do {
                            var3.read(var5);
                        } while(var5.hasRemaining());

                        var5.rewind();
                        if (var5.equals(var4)) {
                            PipeImpl.this.source = new SourceChannelImpl(Initializer.this.sp, var2);
                            PipeImpl.this.sink = new SinkChannelImpl(Initializer.this.sp, var3);
                            break;
                        }

                        var3.close();
                        var2.close();
                    }

首先初始化一个ServerSocketChannel 然后绑定本地回环地址分配端口号

然后var2通过Open和ServerSocketChannel进行连接，紧接着var3通过acceept的方式来接受连接。如此这两个SocketChannel通过ServerSocketChannel建立了连接从而实现了跨线程通信。