CompletableFuture和netty
时间: 2023-11-07 20:05:57 浏览: 43
CompletableFuture是Java 8中引入的一个类,继承了java.util.concurrent.Future接口,它是一种可完成的Future。相比传统的Future,CompletableFuture能够主动设置计算的结果值,从而在某些场景下主动结束阻塞等待。而传统的Future只有在计算结果产生或超时时才会返回。
Netty是一个基于异步事件驱动的网络应用框架,它使用了CompletableFuture来实现异步调用。Netty提供了自己的Future接口,它继承了java.util.concurrent.Future接口,并且扩展了一些重要的方法,比如isSuccess()、addListener()和removeListener()等。
通过使用CompletableFuture和Netty的异步策略,我们可以实现从同步调用到异步调用的转换。使用CompletableFuture的主动设置结果值的特性,结合Netty的异步事件驱动机制,我们可以实现高效的异步编程。
相关问题
jar rpc netty框架代码
以下是一个基于Netty框架的RPC实现示例代码:
1. 服务接口定义
```java
public interface HelloService {
String sayHello(String name);
}
```
2. 服务提供者实现
```java
public class HelloServiceImpl implements HelloService {
public String sayHello(String name) {
return "Hello, " + name;
}
}
```
3. RPC框架实现
```java
public class RpcServer {
private final EventLoopGroup bossGroup;
private final EventLoopGroup workerGroup;
public RpcServer() {
bossGroup = new NioEventLoopGroup();
workerGroup = new NioEventLoopGroup();
}
public void start(int port) throws InterruptedException {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline p = ch.pipeline();
p.addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
p.addLast(new ObjectEncoder());
p.addLast(new RpcServerHandler());
}
})
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true);
ChannelFuture f = b.bind(port).sync();
System.out.println("Server started on port " + port);
f.channel().closeFuture().sync();
}
public void shutdown() {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
public class RpcServerHandler extends ChannelInboundHandlerAdapter {
private static final Map<String, Object> serviceMap = new ConcurrentHashMap<>();
static {
serviceMap.put(HelloService.class.getName(), new HelloServiceImpl());
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof RpcRequest) {
RpcRequest request = (RpcRequest) msg;
Object service = serviceMap.get(request.getClassName());
if (service != null) {
Method method = service.getClass().getMethod(request.getMethodName(), request.getParameterTypes());
Object result = method.invoke(service, request.getParameters());
RpcResponse response = new RpcResponse();
response.setRequestId(request.getRequestId());
response.setResult(result);
ctx.writeAndFlush(response);
}
} else {
super.channelRead(ctx, msg);
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}
```
4. RPC客户端实现
```java
public class RpcClient {
private final EventLoopGroup group;
private final Bootstrap bootstrap;
public RpcClient() {
group = new NioEventLoopGroup();
bootstrap = new Bootstrap();
bootstrap.group(group)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline p = ch.pipeline();
p.addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
p.addLast(new ObjectEncoder());
p.addLast(new RpcClientHandler());
}
});
}
public void connect(String host, int port) throws InterruptedException {
ChannelFuture future = bootstrap.connect(host, port).sync();
future.channel().closeFuture().sync();
}
public void shutdown() {
group.shutdownGracefully();
}
}
public class RpcClientHandler extends ChannelInboundHandlerAdapter {
private final Map<String, RpcFuture> pendingRequests = new ConcurrentHashMap<>();
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof RpcResponse) {
RpcResponse response = (RpcResponse) msg;
RpcFuture future = pendingRequests.get(response.getRequestId());
if (future != null) {
pendingRequests.remove(response.getRequestId());
future.done(response.getResult());
}
} else {
super.channelRead(ctx, msg);
}
}
public RpcFuture sendRequest(RpcRequest request) {
RpcFuture future = new RpcFuture(request);
pendingRequests.put(request.getRequestId(), future);
ctx.writeAndFlush(request);
return future;
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}
public class RpcFuture {
private final RpcRequest request;
private final CompletableFuture<Object> responseFuture;
public RpcFuture(RpcRequest request) {
this.request = request;
responseFuture = new CompletableFuture<>();
}
public void done(Object result) {
responseFuture.complete(result);
}
public CompletableFuture<Object> getResponseFuture() {
return responseFuture;
}
public RpcRequest getRequest() {
return request;
}
}
```
5. RPC请求/响应实体类定义
```java
public class RpcRequest implements Serializable {
private String requestId;
private String className;
private String methodName;
private Class<?>[] parameterTypes;
private Object[] parameters;
// getters and setters
}
public class RpcResponse implements Serializable {
private String requestId;
private Object result;
// getters and setters
}
```
使用示例:
```java
// 启动服务端
RpcServer server = new RpcServer();
server.start(8080);
// 创建客户端
RpcClient client = new RpcClient();
client.connect("localhost", 8080);
// 发送请求
RpcRequest request = new RpcRequest();
request.setRequestId(UUID.randomUUID().toString());
request.setClassName(HelloService.class.getName());
request.setMethodName("sayHello");
request.setParameterTypes(new Class[] { String.class });
request.setParameters(new Object[] { "World" });
RpcFuture future = client.sendRequest(request);
// 处理响应
future.getResponseFuture().thenAccept(result -> {
System.out.println(result);
});
// 关闭客户端和服务端
client.shutdown();
server.shutdown();
```
解析一下代码,并检查问题 public static void start(int[] ports, java.util.function.Consumer<ServerBootstrap> consumer) throws Exception { NioEventLoopGroup bossGroup = new NioEventLoopGroup(); NioEventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap bootstrap = new ServerBootstrap(); bootstrap.group(bossGroup, workerGroup) .channel(NioServerSocketChannel.class) .handler(new LoggingHandler(LogLevel.INFO)); consumer.accept(bootstrap); List<ChannelFuture> list = Arrays.stream(ports).mapToObj(bootstrap::bind).toList(); for (int i = 0; i < list.size(); i++) { final ChannelFuture future = list.get(i); int index = i; CompletableFuture.runAsync(() -> { try { future.sync(); future.channel().closeFuture().sync(); } catch (InterruptedException e) { log().error("bind {} port exception: ", ports[index], e); } }); } } finally { workerGroup.shutdownGracefully(); bossGroup.shutdownGracefully(); } }
这段代码使用了Netty框架来启动一个服务器并定多个端口。下面是代码的解析和问题的检查:
1. 首先,创建了两个`NioEventLoopGroup`对象,分别用于处理服务器的连接请求(bossGroup)和处理已经建立连接的网络通信(workerGroup)。
2. 然后,创建了一个`ServerBootstrap`对象,并将bossGroup和workerGroup设置到该对象中。
3. 调用`bootstrap.channel(NioServerSocketChannel.class)`设置服务器的通道类型为NIO类型。
4. 使用`LoggingHandler`设置日志级别为INFO。
5. 调用`consumer.accept(bootstrap)`方法,允许用户自定义配置`ServerBootstrap`实例。
6. 使用流式操作,将输入的`ports`数组转换为一个`List<ChannelFuture>`对象。在这个过程中,对于每个端口,调用`bootstrap.bind`方法来绑定端口,并将返回的`ChannelFuture`对象添加到列表中。
7. 在循环中,使用`CompletableFuture.runAsync()`方法来异步地执行端口绑定和关闭操作。通过调用`future.sync()`方法等待绑定完成,并调用`future.channel().closeFuture().sync()`等待通道关闭。
8. 在捕获异常的块中,记录绑定异常并打印日志。
9. 最后,在finally块中,调用`workerGroup.shutdownGracefully()`和`bossGroup.shutdownGracefully()`来优雅地关闭线程组,释放资源。
问题检查:
- 通过使用`CompletableFuture.runAsync()`来异步执行端口绑定和关闭操作,代码在绑定和关闭过程中不会阻塞主线程,提高了并发能力。
- 通过捕获异常并记录日志,代码增加了容错性,可以更好地处理绑定异常的情况。
- 但是,需要注意的是,在循环中创建并执行`CompletableFuture`对象可能会导致大量的线程创建和调度开销。如果同时绑定的端口数量非常大,可能会导致资源消耗过高。可以根据实际情况调整并发度,避免创建过多的线程。
- 此外,代码中没有处理已绑定端口的关闭操作,如果需要在某个时刻关闭已绑定的端口,需要额外的逻辑来处理。
相关推荐
![rar](https://img-home.csdnimg.cn/images/20210720083606.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![7z](https://img-home.csdnimg.cn/images/20210720083312.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![rar](https://img-home.csdnimg.cn/images/20210720083606.png)
![rar](https://img-home.csdnimg.cn/images/20210720083606.png)