优化
# 1. 扩展序列化算法
序列化，反序列化主要用在消息正文的转换上
- 序列化时，需要将 Java 对象变为要传输的数据（可以是 byte[]，或 json 等，最终都需要变成 byte[]）
- 反序列化时，需要将传入的正文数据还原成 Java 对象，便于处理
目前的代码仅支持 Java 自带的序列化，反序列化机制，核心代码如下
// 反序列化
byte[] body = new byte[bodyLength];
byteByf.readBytes(body);
ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(body));
Message message = (Message) in.readObject();
message.setSequenceId(sequenceId);
// 序列化
ByteArrayOutputStream out = new ByteArrayOutputStream();
new ObjectOutputStream(out).writeObject(message);
byte[] bytes = out.toByteArray();
为了支持更多序列化算法，抽象一个 Serializer 接口
public interface Serializer {
// 反序列化方法
<T> T deserialize(Class<T> clazz, byte[] bytes);
// 序列化方法
<T> byte[] serialize(T object);
}
提供两个实现，我这里直接将实现加入了枚举类 Serializer.Algorithm 中
enum SerializerAlgorithm implements Serializer {
// Java 实现
Java {
@Override
public <T> T deserialize(Class<T> clazz, byte[] bytes) {
try {
ObjectInputStream in =
new ObjectInputStream(new ByteArrayInputStream(bytes));
Object object = in.readObject();
return (T) object;
} catch (IOException | ClassNotFoundException e) {
throw new RuntimeException("SerializerAlgorithm.Java 反序列化错误", e);
}
}
@Override
public <T> byte[] serialize(T object) {
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
new ObjectOutputStream(out).writeObject(object);
return out.toByteArray();
} catch (IOException e) {
throw new RuntimeException("SerializerAlgorithm.Java 序列化错误", e);
}
}
},
// Json 实现(引入了 Gson 依赖)
Json {
@Override
public <T> T deserialize(Class<T> clazz, byte[] bytes) {
return new Gson().fromJson(new String(bytes, StandardCharsets.UTF_8), clazz);
}
@Override
public <T> byte[] serialize(T object) {
return new Gson().toJson(object).getBytes(StandardCharsets.UTF_8);
}
};
// 需要从协议的字节中得到是哪种序列化算法
public static SerializerAlgorithm getByInt(int type) {
SerializerAlgorithm[] array = SerializerAlgorithm.values();
if (type < 0 || type > array.length - 1) {
throw new IllegalArgumentException("超过 SerializerAlgorithm 范围");
}
return array[type];
}
}
增加配置类和配置文件
public abstract class Config {
static Properties properties;
static {
try (InputStream in = Config.class.getResourceAsStream("/application.properties")) {
properties = new Properties();
properties.load(in);
} catch (IOException e) {
throw new ExceptionInInitializerError(e);
}
}
public static int getServerPort() {
String value = properties.getProperty("server.port");
if(value == null) {
return 8080;
} else {
return Integer.parseInt(value);
}
}
public static Serializer.Algorithm getSerializerAlgorithm() {
String value = properties.getProperty("serializer.algorithm");
if(value == null) {
return Serializer.Algorithm.Java;
} else {
return Serializer.Algorithm.valueOf(value);
}
}
}
配置文件
serializer.algorithm=Json
修改编解码器
/**
* 必须和 LengthFieldBasedFrameDecoder 一起使用，确保接到的 ByteBuf 消息是完整的
*/
public class MessageCodecSharable extends MessageToMessageCodec<ByteBuf, Message> {
@Override
public void encode(ChannelHandlerContext ctx, Message msg, List<Object> outList) throws Exception {
ByteBuf out = ctx.alloc().buffer();
// 1. 4 字节的魔数
out.writeBytes(new byte[]{1, 2, 3, 4});
// 2. 1 字节的版本,
out.writeByte(1);
// 3. 1 字节的序列化方式 jdk 0 , json 1
out.writeByte(Config.getSerializerAlgorithm().ordinal());
// 4. 1 字节的指令类型
out.writeByte(msg.getMessageType());
// 5. 4 个字节
out.writeInt(msg.getSequenceId());
// 无意义，对齐填充
out.writeByte(0xff);
// 6. 获取内容的字节数组
byte[] bytes = Config.getSerializerAlgorithm().serialize(msg);
// 7. 长度
out.writeInt(bytes.length);
// 8. 写入内容
out.writeBytes(bytes);
outList.add(out);
}
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
int magicNum = in.readInt();
byte version = in.readByte();
byte serializerAlgorithm = in.readByte(); // 0 或 1
byte messageType = in.readByte(); // 0,1,2...
int sequenceId = in.readInt();
in.readByte();
int length = in.readInt();
byte[] bytes = new byte[length];
in.readBytes(bytes, 0, length);
// 找到反序列化算法
Serializer.Algorithm algorithm = Serializer.Algorithm.values()[serializerAlgorithm];
// 确定具体消息类型
Class<? extends Message> messageClass = Message.getMessageClass(messageType);
Message message = algorithm.deserialize(messageClass, bytes);
// log.debug("{}, {}, {}, {}, {}, {}", magicNum, version, serializerType, messageType, sequenceId, length);
// log.debug("{}", message);
out.add(message);
}
}
其中确定具体消息类型，可以根据 消息类型字节 获取到对应的 消息 class
@Data
public abstract class Message implements Serializable {
/**
* 根据消息类型字节，获得对应的消息 class
* @param messageType 消息类型字节
* @return 消息 class
*/
public static Class<? extends Message> getMessageClass(int messageType) {
return messageClasses.get(messageType);
}
private int sequenceId;
private int messageType;
public abstract int getMessageType();
public static final int LoginRequestMessage = 0;
public static final int LoginResponseMessage = 1;
public static final int ChatRequestMessage = 2;
public static final int ChatResponseMessage = 3;
public static final int GroupCreateRequestMessage = 4;
public static final int GroupCreateResponseMessage = 5;
public static final int GroupJoinRequestMessage = 6;
public static final int GroupJoinResponseMessage = 7;
public static final int GroupQuitRequestMessage = 8;
public static final int GroupQuitResponseMessage = 9;
public static final int GroupChatRequestMessage = 10;
public static final int GroupChatResponseMessage = 11;
public static final int GroupMembersRequestMessage = 12;
public static final int GroupMembersResponseMessage = 13;
public static final int PingMessage = 14;
public static final int PongMessage = 15;
private static final Map<Integer, Class<? extends Message>> messageClasses = new HashMap<>();
static {
messageClasses.put(LoginRequestMessage, LoginRequestMessage.class);
messageClasses.put(LoginResponseMessage, LoginResponseMessage.class);
messageClasses.put(ChatRequestMessage, ChatRequestMessage.class);
messageClasses.put(ChatResponseMessage, ChatResponseMessage.class);
messageClasses.put(GroupCreateRequestMessage, GroupCreateRequestMessage.class);
messageClasses.put(GroupCreateResponseMessage, GroupCreateResponseMessage.class);
messageClasses.put(GroupJoinRequestMessage, GroupJoinRequestMessage.class);
messageClasses.put(GroupJoinResponseMessage, GroupJoinResponseMessage.class);
messageClasses.put(GroupQuitRequestMessage, GroupQuitRequestMessage.class);
messageClasses.put(GroupQuitResponseMessage, GroupQuitResponseMessage.class);
messageClasses.put(GroupChatRequestMessage, GroupChatRequestMessage.class);
messageClasses.put(GroupChatResponseMessage, GroupChatResponseMessage.class);
messageClasses.put(GroupMembersRequestMessage, GroupMembersRequestMessage.class);
messageClasses.put(GroupMembersResponseMessage, GroupMembersResponseMessage.class);
}
}
# 2. 参数调优
# 1）CONNECT_TIMEOUT_MILLIS
属于 SocketChannal 参数
用在客户端建立连接时，如果在指定毫秒内无法连接，会抛出 timeout 异常
SO_TIMEOUT 主要用在阻塞 IO，阻塞 IO 中 accept，read 等都是无限等待的，如果不希望永远阻塞，使用它调整超时时间
@Slf4j
public class TestConnectionTimeout {
public static void main(String[] args) {
NioEventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap()
.group(group)
.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 300)
.channel(NioSocketChannel.class)
.handler(new LoggingHandler());
ChannelFuture future = bootstrap.connect("127.0.0.1", 8080);
future.sync().channel().closeFuture().sync(); // 断点1
} catch (Exception e) {
e.printStackTrace();
log.debug("timeout");
} finally {
group.shutdownGracefully();
}
}
}
另外源码部分 io.netty.channel.nio.AbstractNioChannel.AbstractNioUnsafe#connect
@Override
public final void connect(
final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) {
// ...
// Schedule connect timeout.
int connectTimeoutMillis = config().getConnectTimeoutMillis();
if (connectTimeoutMillis > 0) {
connectTimeoutFuture = eventLoop().schedule(new Runnable() {
@Override
public void run() {
ChannelPromise connectPromise = AbstractNioChannel.this.connectPromise;
ConnectTimeoutException cause =
new ConnectTimeoutException("connection timed out: " + remoteAddress); // 断点2
if (connectPromise != null && connectPromise.tryFailure(cause)) {
close(voidPromise());
}
}
}, connectTimeoutMillis, TimeUnit.MILLISECONDS);
}
// ...
}
# 2）SO_BACKLOG
- 属于 ServerSocketChannal 参数
sequenceDiagram
participant c as client
participant s as server
participant sq as syns queue
participant aq as accept queue
s ->> s : bind()
s ->> s : listen()
c ->> c : connect()
c ->> s : 1. SYN
Note left of c : SYN_SEND
s ->> sq : put
Note right of s : SYN_RCVD
s ->> c : 2. SYN + ACK
Note left of c : ESTABLISHED
c ->> s : 3. ACK
sq ->> aq : put
Note right of s : ESTABLISHED
aq -->> s :
s ->> s : accept()
- 第一次握手，client 发送 SYN 到 server，状态修改为 SYN_SEND，server 收到，状态改变为 SYN_REVD，并将该请求放入 sync queue 队列
- 第二次握手，server 回复 SYN + ACK 给 client，client 收到，状态改变为 ESTABLISHED，并发送 ACK 给 server
- 第三次握手，server 收到 ACK，状态改变为 ESTABLISHED，将该请求从 sync queue 放入 accept queue
其中
在 linux 2.2 之前，backlog 大小包括了两个队列的大小，在 2.2 之后，分别用下面两个参数来控制
sync queue - 半连接队列
- 大小通过 /proc/sys/net/ipv4/tcp_max_syn_backlog 指定，在
syncookies启用的情况下，逻辑上没有最大值限制，这个设置便被忽略
- 大小通过 /proc/sys/net/ipv4/tcp_max_syn_backlog 指定，在
accept queue - 全连接队列
- 其大小通过 /proc/sys/net/core/somaxconn 指定，在使用 listen 函数时，内核会根据传入的 backlog 参数与系统参数，取二者的较小值
- 如果 accpet queue 队列满了，server 将发送一个拒绝连接的错误信息到 client
netty 中
可以通过 option(ChannelOption.SO_BACKLOG, 值) 来设置大小
可以通过下面源码查看默认大小
public class DefaultServerSocketChannelConfig extends DefaultChannelConfig
implements ServerSocketChannelConfig {
private volatile int backlog = NetUtil.SOMAXCONN;
// ...
}
课堂调试关键断点为：io.netty.channel.nio.NioEventLoop#processSelectedKey
oio 中更容易说明，不用 debug 模式
public class Server {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(8888, 2);
Socket accept = ss.accept();
System.out.println(accept);
System.in.read();
}
}
客户端启动 4 个
public class Client {
public static void main(String[] args) throws IOException {
try {
Socket s = new Socket();
System.out.println(new Date()+" connecting...");
s.connect(new InetSocketAddress("localhost", 8888),1000);
System.out.println(new Date()+" connected...");
s.getOutputStream().write(1);
System.in.read();
} catch (IOException e) {
System.out.println(new Date()+" connecting timeout...");
e.printStackTrace();
}
}
}
第 1，2，3 个客户端都打印，但除了第一个处于 accpet 外，其它两个都处于 accept queue 中
Tue Apr 21 20:30:28 CST 2020 connecting...
Tue Apr 21 20:30:28 CST 2020 connected...
第 4 个客户端连接时
Tue Apr 21 20:53:58 CST 2020 connecting...
Tue Apr 21 20:53:59 CST 2020 connecting timeout...
java.net.SocketTimeoutException: connect timed out
# 3）ulimit -n
- 属于操作系统参数
# 4）TCP_NODELAY
- 属于 SocketChannal 参数
# 5）SO_SNDBUF & SO_RCVBUF
- SO_SNDBUF 属于 SocketChannal 参数
- SO_RCVBUF 既可用于 SocketChannal 参数，也可以用于 ServerSocketChannal 参数（建议设置到 ServerSocketChannal 上）
# 6）ALLOCATOR
- 属于 SocketChannal 参数
- 用来分配 ByteBuf， ctx.alloc()
# 7）RCVBUF_ALLOCATOR
- 属于 SocketChannal 参数
- 控制 netty 接收缓冲区大小
- 负责入站数据的分配，决定入站缓冲区的大小（并可动态调整），统一采用 direct 直接内存，具体池化还是非池化由 allocator 决定
# 3. RPC 框架
# 1）准备工作
这些代码可以认为是现成的，无需从头编写练习
为了简化起见，在原来聊天项目的基础上新增 Rpc 请求和响应消息
@Data
public abstract class Message implements Serializable {
// 省略旧的代码
public static final int RPC_MESSAGE_TYPE_REQUEST = 101;
public static final int RPC_MESSAGE_TYPE_RESPONSE = 102;
static {
// ...
messageClasses.put(RPC_MESSAGE_TYPE_REQUEST, RpcRequestMessage.class);
messageClasses.put(RPC_MESSAGE_TYPE_RESPONSE, RpcResponseMessage.class);
}
}
请求消息
@Getter
@ToString(callSuper = true)
public class RpcRequestMessage extends Message {
/**
* 调用的接口全限定名，服务端根据它找到实现
*/
private String interfaceName;
/**
* 调用接口中的方法名
*/
private String methodName;
/**
* 方法返回类型
*/
private Class<?> returnType;
/**
* 方法参数类型数组
*/
private Class[] parameterTypes;
/**
* 方法参数值数组
*/
private Object[] parameterValue;
public RpcRequestMessage(int sequenceId, String interfaceName, String methodName, Class<?> returnType, Class[] parameterTypes, Object[] parameterValue) {
super.setSequenceId(sequenceId);
this.interfaceName = interfaceName;
this.methodName = methodName;
this.returnType = returnType;
this.parameterTypes = parameterTypes;
this.parameterValue = parameterValue;
}
@Override
public int getMessageType() {
return RPC_MESSAGE_TYPE_REQUEST;
}
}
响应消息
@Data
@ToString(callSuper = true)
public class RpcResponseMessage extends Message {
/**
* 返回值
*/
private Object returnValue;
/**
* 异常值
*/
private Exception exceptionValue;
@Override
public int getMessageType() {
return RPC_MESSAGE_TYPE_RESPONSE;
}
}
服务器架子
@Slf4j
public class RpcServer {
public static void main(String[] args) {
NioEventLoopGroup boss = new NioEventLoopGroup();
NioEventLoopGroup worker = new NioEventLoopGroup();
LoggingHandler LOGGING_HANDLER = new LoggingHandler(LogLevel.DEBUG);
MessageCodecSharable MESSAGE_CODEC = new MessageCodecSharable();
// rpc 请求消息处理器，待实现
RpcRequestMessageHandler RPC_HANDLER = new RpcRequestMessageHandler();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.channel(NioServerSocketChannel.class);
serverBootstrap.group(boss, worker);
serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new ProcotolFrameDecoder());
ch.pipeline().addLast(LOGGING_HANDLER);
ch.pipeline().addLast(MESSAGE_CODEC);
ch.pipeline().addLast(RPC_HANDLER);
}
});
Channel channel = serverBootstrap.bind(8080).sync().channel();
channel.closeFuture().sync();
} catch (InterruptedException e) {
log.error("server error", e);
} finally {
boss.shutdownGracefully();
worker.shutdownGracefully();
}
}
}
客户端架子
public class RpcClient {
public static void main(String[] args) {
NioEventLoopGroup group = new NioEventLoopGroup();
LoggingHandler LOGGING_HANDLER = new LoggingHandler(LogLevel.DEBUG);
MessageCodecSharable MESSAGE_CODEC = new MessageCodecSharable();
// rpc 响应消息处理器，待实现
RpcResponseMessageHandler RPC_HANDLER = new RpcResponseMessageHandler();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.channel(NioSocketChannel.class);
bootstrap.group(group);
bootstrap.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new ProcotolFrameDecoder());
ch.pipeline().addLast(LOGGING_HANDLER);
ch.pipeline().addLast(MESSAGE_CODEC);
ch.pipeline().addLast(RPC_HANDLER);
}
});
Channel channel = bootstrap.connect("localhost", 8080).sync().channel();
channel.closeFuture().sync();
} catch (Exception e) {
log.error("client error", e);
} finally {
group.shutdownGracefully();
}
}
}
服务器端的 service 获取
public class ServicesFactory {
static Properties properties;
static Map<Class<?>, Object> map = new ConcurrentHashMap<>();
static {
try (InputStream in = Config.class.getResourceAsStream("/application.properties")) {
properties = new Properties();
properties.load(in);
Set<String> names = properties.stringPropertyNames();
for (String name : names) {
if (name.endsWith("Service")) {
Class<?> interfaceClass = Class.forName(name);
Class<?> instanceClass = Class.forName(properties.getProperty(name));
map.put(interfaceClass, instanceClass.newInstance());
}
}
} catch (IOException | ClassNotFoundException | InstantiationException | IllegalAccessException e) {
throw new ExceptionInInitializerError(e);
}
}
public static <T> T getService(Class<T> interfaceClass) {
return (T) map.get(interfaceClass);
}
}
相关配置 application.properties
serializer.algorithm=Json
cn.itcast.server.service.HelloService=cn.itcast.server.service.HelloServiceImpl
# 2）服务器 handler
@Slf4j
@ChannelHandler.Sharable
public class RpcRequestMessageHandler extends SimpleChannelInboundHandler<RpcRequestMessage> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RpcRequestMessage message) {
RpcResponseMessage response = new RpcResponseMessage();
response.setSequenceId(message.getSequenceId());
try {
// 获取真正的实现对象
HelloService service = (HelloService)
ServicesFactory.getService(Class.forName(message.getInterfaceName()));
// 获取要调用的方法
Method method = service.getClass().getMethod(message.getMethodName(), message.getParameterTypes());
// 调用方法
Object invoke = method.invoke(service, message.getParameterValue());
// 调用成功
response.setReturnValue(invoke);
} catch (Exception e) {
e.printStackTrace();
// 调用异常
response.setExceptionValue(e);
}
// 返回结果
ctx.writeAndFlush(response);
}
}
# 3）客户端代码第一版
只发消息
@Slf4j
public class RpcClient {
public static void main(String[] args) {
NioEventLoopGroup group = new NioEventLoopGroup();
LoggingHandler LOGGING_HANDLER = new LoggingHandler(LogLevel.DEBUG);
MessageCodecSharable MESSAGE_CODEC = new MessageCodecSharable();
RpcResponseMessageHandler RPC_HANDLER = new RpcResponseMessageHandler();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.channel(NioSocketChannel.class);
bootstrap.group(group);
bootstrap.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new ProcotolFrameDecoder());
ch.pipeline().addLast(LOGGING_HANDLER);
ch.pipeline().addLast(MESSAGE_CODEC);
ch.pipeline().addLast(RPC_HANDLER);
}
});
Channel channel = bootstrap.connect("localhost", 8080).sync().channel();
ChannelFuture future = channel.writeAndFlush(new RpcRequestMessage(
1,
"cn.itcast.server.service.HelloService",
"sayHello",
String.class,
new Class[]{String.class},
new Object[]{"张三"}
)).addListener(promise -> {
if (!promise.isSuccess()) {
Throwable cause = promise.cause();
log.error("error", cause);
}
});
channel.closeFuture().sync();
} catch (Exception e) {
log.error("client error", e);
} finally {
group.shutdownGracefully();
}
}
}
# 4）客户端 handler 第一版
@Slf4j
@ChannelHandler.Sharable
public class RpcResponseMessageHandler extends SimpleChannelInboundHandler<RpcResponseMessage> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RpcResponseMessage msg) throws Exception {
log.debug("{}", msg);
}
}
# 5）客户端代码 第二版
包括 channel 管理，代理，接收结果
@Slf4j
public class RpcClientManager {
public static void main(String[] args) {
HelloService service = getProxyService(HelloService.class);
System.out.println(service.sayHello("zhangsan"));
// System.out.println(service.sayHello("lisi"));
// System.out.println(service.sayHello("wangwu"));
}
// 创建代理类
public static <T> T getProxyService(Class<T> serviceClass) {
ClassLoader loader = serviceClass.getClassLoader();
Class<?>[] interfaces = new Class[]{serviceClass};
// sayHello "张三"
Object o = Proxy.newProxyInstance(loader, interfaces, (proxy, method, args) -> {
// 1. 将方法调用转换为 消息对象
int sequenceId = SequenceIdGenerator.nextId();
RpcRequestMessage msg = new RpcRequestMessage(
sequenceId,
serviceClass.getName(),
method.getName(),
method.getReturnType(),
method.getParameterTypes(),
args
);
// 2. 将消息对象发送出去
getChannel().writeAndFlush(msg);
// 3. 准备一个空 Promise 对象，来接收结果 指定 promise 对象异步接收结果线程
DefaultPromise<Object> promise = new DefaultPromise<>(getChannel().eventLoop());
RpcResponseMessageHandler.PROMISES.put(sequenceId, promise);
// promise.addListener(future -> {
// // 线程
// });
// 4. 等待 promise 结果
promise.await();
if(promise.isSuccess()) {
// 调用正常
return promise.getNow();
} else {
// 调用失败
throw new RuntimeException(promise.cause());
}
});
return (T) o;
}
private static Channel channel = null;
private static final Object LOCK = new Object();
// 获取唯一的 channel 对象
public static Channel getChannel() {
if (channel != null) {
return channel;
}
synchronized (LOCK) { // t2
if (channel != null) { // t1
return channel;
}
initChannel();
return channel;
}
}
// 初始化 channel 方法
private static void initChannel() {
NioEventLoopGroup group = new NioEventLoopGroup();
LoggingHandler LOGGING_HANDLER = new LoggingHandler(LogLevel.DEBUG);
MessageCodecSharable MESSAGE_CODEC = new MessageCodecSharable();
RpcResponseMessageHandler RPC_HANDLER = new RpcResponseMessageHandler();
Bootstrap bootstrap = new Bootstrap();
bootstrap.channel(NioSocketChannel.class);
bootstrap.group(group);
bootstrap.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new ProcotolFrameDecoder());
ch.pipeline().addLast(LOGGING_HANDLER);
ch.pipeline().addLast(MESSAGE_CODEC);
ch.pipeline().addLast(RPC_HANDLER);
}
});
try {
channel = bootstrap.connect("localhost", 8080).sync().channel();
channel.closeFuture().addListener(future -> {
group.shutdownGracefully();
});
} catch (Exception e) {
log.error("client error", e);
}
}
}
# 6）客户端 handler 第二版
@Slf4j
@ChannelHandler.Sharable
public class RpcResponseMessageHandler extends SimpleChannelInboundHandler<RpcResponseMessage> {
// 序号 用来接收结果的 promise 对象
public static final Map<Integer, Promise<Object>> PROMISES = new ConcurrentHashMap<>();
@Override
protected void channelRead0(ChannelHandlerContext ctx, RpcResponseMessage msg) throws Exception {
log.debug("{}", msg);
// 拿到空的 promise
Promise<Object> promise = PROMISES.remove(msg.getSequenceId());
if (promise != null) {
Object returnValue = msg.getReturnValue();
Exception exceptionValue = msg.getExceptionValue();
if(exceptionValue != null) {
promise.setFailure(exceptionValue);
} else {
promise.setSuccess(returnValue);
}
}
}
}
上次更新: 2025/03/09, 18:29:07