java7中三个异步通道
1.AsynchronousFileChannle:用于文件I/O
2.AsynchronousSockeChannle:用于套接字I/O,支持连接超时
3.AsynchronousServerSocketChannle:用于套接字接收异步连接
一.将来式
试用场景：需要读取文件的过程中还要做其他的事情。
代码演示：
public static void main(String[] args) {
Path path = Paths.get("C:\\Users\\Administrator\\Desktop\\api\\Java程序员修炼之道.pdf");
try {
AsynchronousFileChannel asynchronousFileChannel = AsynchronousFileChannel.open(path);
ByteBuffer buffer = ByteBuffer.allocate(100_000_0);
Future<Integer> result = asynchronousFileChannel.read(buffer, 0);
//do something
while (!result.isDone()) {
System.out.println("test");
}
//结果
Integer byteLen = result.get();
System.out.println("bytes read="+byteLen);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
二.回调式
试用场景：在I/O操作刚一成功或一失败时，需要马上采取行动，此时需要回调式I/O操作
代码：
public static void main(String[] args) {
Path file = Paths.get("C:\\Users\\Administrator\\Desktop\\api\\Java程序员修炼之道.pdf");
try {
ByteBuffer buffer = ByteBuffer.allocate(100_000);
AsynchronousFileChannel channle = AsynchronousFileChannel.open(file);
channle.read(buffer, 0, buffer, new CompletionHandler<Integer, ByteBuffer>() {
@Override
public void completed(Integer result, ByteBuffer attachment) {
System.out.println("bytes read="+result);
}
@Override
public void failed(Throwable exc, ByteBuffer attachment) {
System.out.println("test"+exc.getMessage());
}
});
} catch (IOException e) {
e.printStackTrace();
}
}