如何设置 Spring TCP 客户端和服务器模型？

Question

所以按照这个问题（how to plug a TCP-IP client server in a spring MVC application）， 我成功地将网关连接到我的 Spring REST 控制器。但是，我对下一步去哪里感到困惑。这是我想要完成的任务：

1) 当某个路由被 POST 请求命中时，打开一个从 POST 传递过来的到某个 IP 的连接（或使用已经使用该 IP 打开的连接）并发送一条消息。

@RequestMethod(value = '/sendTcpMessage', method=RequestMethod.POST)
public void sendTcpMessage(@RequestParam(value="ipAddress", required=true) String ipAddress,
                           @RequestParam(value="message", required=true) String message) {

//send the message contained in the 'message' variable to the IP address located 
//at 'ipAddress' - how do I do this?

}

2) 我还需要我的 Spring 后端来监听传递给它的 TCP“消息”，并将它们存储在缓冲区中。我的 Javascript 将每 5 秒左右调用一次路由，并从缓冲区中读取信息。

这是我的控制器代码：

@Controller
public class HomeController {

    @Resource(name = "userDaoImpl")
    private UserDAO userDao;
    @Resource(name = "receiveTcp")
    private ReceiveTcp tcpMessageReceiver;
    @Autowired
    SimpleGateway gw;

    String tcpBuffer[] = new String[100];

    @RequestMapping(value="/")
    public String home() {
        return "homepage";
    }

    @RequestMapping(value = "/checkTcpBuffer", method=RequestMethod.POST)
    public String[] passTcpBuffer() {
        return tcpMessageReceiver.transferBuffer();
    }

}

根上下文.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:int="http://www.springframework.org/schema/integration"
    xmlns:int-ip="http://www.springframework.org/schema/integration/ip"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                        http://www.springframework.org/schema/integration/ip http://www.springframework.org/schema/integration/ip/spring-integration-ip.xsd
                        http://www.springframework.org/schema/integration/ http://www.springframework.org/schema/integration/spring-integration.xsd">

    <!-- Root Context: defines shared resources visible to all other web components -->
<int:gateway id="gw"
   service-interface="net.codejava.spring.interfaces.SimpleGateway"
   default-request-channel="input"/>

<bean id="javaSerializer"
      class="org.springframework.core.serializer.DefaultSerializer"/>
<bean id="javaDeserializer"
      class="org.springframework.core.serializer.DefaultDeserializer"/>

<int-ip:tcp-connection-factory id="server"
    type="server"
    port="8081"
    deserializer="javaDeserializer"
    serializer="javaSerializer"
    using-nio="true"
    single-use="true"/>

<int-ip:tcp-connection-factory id="client"
    type="client"
    host="localhost"
    port="8081"
    single-use="true"
    so-timeout="10000"
    deserializer="javaDeserializer"
    serializer="javaSerializer"/>

    <int:channel id="input" />

    <int:channel id="replies">
        <int:queue/>
    </int:channel>

    <int-ip:tcp-outbound-channel-adapter id="outboundClient"
    channel="input"
    connection-factory="client"/>

    <int-ip:tcp-inbound-channel-adapter id="inboundClient"
    channel="replies"
    connection-factory="client"/>

    <int-ip:tcp-inbound-channel-adapter id="inboundServer"
    channel="loop"
    connection-factory="server"/>

    <int-ip:tcp-outbound-channel-adapter id="outboundServer"
    channel="loop"
    connection-factory="server"/>

    <int:service-activator input-channel="input" ref="receiveTcp" method = "saveValue"/>

</beans>

ReceiveTcp.java

@Component(value = "receiveTcp")
public class ReceiveTcp {

    String buf[] = new String[100];
    int currentPosition = 0;

    @ServiceActivator
    public void saveValue(String value){
        System.out.println(value);
        buf[currentPosition] = value;
        currentPosition++;
    }

    public String[] transferBuffer() {
        String tempBuf[] = new String[100];
        tempBuf = buf;
        buf = new String[100];

        return tempBuf;
    }
}

我该如何解决这些问题？

Answer 1

您需要使用ResponseEntity。请参阅此answer。 tcp 连接是双向连接，因此如果您的方法返回响应而不是 void，它会自动将其发送回向您发出请求的 ip。您不必手动执行此操作。

Answer 2

请参阅tcp-client-server sample。它使用 TCP 网关（请求/回复）。根据您的情况，您可能希望改用单向通道适配器。

gateway(with void return) -> tcp-outbound-channel-adapter

和

tcp-inbound-channel-adapter -> service-activator

（服务激活器调用一个 POJO，它将入站消息保存在您的“缓冲区”中，可能由 connectionId 键入 - 从消息头中获取）。

将服务激活器引用的网关和 POJO 注入您的控制器，以便您可以 (a) 发送消息和 (b) 清空“缓冲区”。

您还可以收听TcpConnectionEvents，以便检测连接是否丢失。