Spring Integration和TCP服務器套接字 - 如何向客戶端發送消息？

Question

我正在嘗試在Spring中創建一個服務器，它正在偵聽TCP端口並接受連接。 我知道如何將傳入的請求路由到我的服務，它可以響應這些請求。 但是我想在沒有收到任何請求的情況下向某些客戶發送消息。 例如，有時我必須告知客戶它已收到消息。

為此，我認為我需要一種方法來識別客戶端，例如讓他們登錄。有沒有辦法為每個活動連接都有一個“會話”對象，我可以在其中存儲登錄數據？

如何向使用用戶名X登錄的客戶端發送消息？

這在春天有可能嗎？

Answer 1

從3.0版開始; 當連接狀態發生變化時 ，框架現在會發出連接事件 。 您可以使用ApplicationListener或使用<event:inbound-channel-adapter/>捕獲這些事件。

TcpConnectionOpenEvent包含connectionId ; 通過在消息中填充IpHeaders.connectionId標頭（ ip_connectionId ）並將其發送到<tcp:outbound-channel-adapter/>您可以在知道其id后將任意消息發送到任何連接。

如果您需要支持請求/回復以及發送任意消息，則需要為所有通信使用協作的通道適配器對，而不是網關。

編輯

這是一個簡單的啟動應用程序......

package com.example;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.Socket;

import javax.net.SocketFactory;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.channel.QueueChannel;
import org.springframework.integration.dsl.IntegrationFlow;
import org.springframework.integration.dsl.IntegrationFlows;
import org.springframework.integration.ip.IpHeaders;
import org.springframework.integration.ip.tcp.TcpReceivingChannelAdapter;
import org.springframework.integration.ip.tcp.TcpSendingMessageHandler;
import org.springframework.integration.ip.tcp.connection.TcpConnectionOpenEvent;
import org.springframework.integration.ip.tcp.connection.TcpNetServerConnectionFactory;
import org.springframework.integration.ip.tcp.connection.TcpServerConnectionFactory;
import org.springframework.integration.support.MessageBuilder;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;

@SpringBootApplication
public class So25102101Application {

    public static void main(String[] args) throws Exception {
        ConfigurableApplicationContext context = new SpringApplicationBuilder(So25102101Application.class)
                .web(false)
                .run(args);
        int port = context.getBean(TcpServerConnectionFactory.class).getPort();
        Socket socket = SocketFactory.getDefault().createSocket("localhost", port);
        BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        String line = reader.readLine();
        System.out.println(line);
        context.close();
    }

    @Bean
    public TcpReceivingChannelAdapter server(TcpNetServerConnectionFactory cf) {
        TcpReceivingChannelAdapter adapter = new TcpReceivingChannelAdapter();
        adapter.setConnectionFactory(cf);
        adapter.setOutputChannel(inputChannel());
        return adapter;
    }

    @Bean
    public MessageChannel inputChannel() {
        return new QueueChannel();
    }

    @Bean
    public MessageChannel outputChannel() {
        return new DirectChannel();
    }

    @Bean
    public TcpNetServerConnectionFactory cf() {
        return new TcpNetServerConnectionFactory(0);
    }

    @Bean
    public IntegrationFlow outbound() {
        return IntegrationFlows.from(outputChannel())
                .handle(sender())
                .get();
    }

    @Bean
    public MessageHandler sender() {
        TcpSendingMessageHandler tcpSendingMessageHandler = new TcpSendingMessageHandler();
        tcpSendingMessageHandler.setConnectionFactory(cf());
        return tcpSendingMessageHandler;
    }

    @Bean
    public ApplicationListener<TcpConnectionOpenEvent> listener() {
        return new ApplicationListener<TcpConnectionOpenEvent>() {

            @Override
            public void onApplicationEvent(TcpConnectionOpenEvent event) {
                outputChannel().send(MessageBuilder.withPayload("foo")
                        .setHeader(IpHeaders.CONNECTION_ID, event.getConnectionId())
                        .build());
            }

        };
    }

}

pom deps：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-integration</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.integration</groupId>
        <artifactId>spring-integration-ip</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>