ServerSocketChannel 可以监听传入的TCP连接，与Java标准库的ServerSocket类似。
举个例子：
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.socket().bind(new InetSocketAddress(9999));
while(true){
SocketChannel socketChannel = serverSocketChannel.accept();
//do something with socketChannel...
}
打开 ServerSocketChannel
通过调用ServerSocketChannel.open()方法来打开ServerSocketChannel
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
关闭 ServerSocketChannel
ServerSocketChannel.close()
监听 传入连接
通过调用ServerSocketChannel.accept()方法来监听传入连接。当accept()方法返回结果时，返回的是一个有传入连接的SocketChannel，因此此方法是阻塞的，会一直阻塞直到有连接传入。
一般循环调用此方法:
while(true){
SocketChannel socketChannel = serverSocketChannel.accept();
// todo
}
别忘了跳出循环…
非阻塞模式
ServerSocketChannel 也是可以被置为非阻塞模式的。在非阻塞模式下，accept()会立即返回，因此如果没有传入连接时可能返回null。所以需要检测是否返回的是null。
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.socket().bind(new InetSocketAddress(9999));
serverSocketChannel.configureBlocking(false);
while(true){
SocketChannel socketChannel = serverSocketChannel.accept();
if(socketChannel != null){
//do something with socketChannel...
}
}