# 应用示例
#### 应用场景
本小节介绍WebSocket建链、信息订阅、信息推送以及心跳保持的调用顺序。
#### 业务流程
WebSocket建链、订阅、信息推送的流程图如下：
图1Websocket消息推送流程图
1. 根据会议ID及主持人密码获取会控Token和建链Websocket所需的服务端地址。请参考"[获取会控Token - CreateConfToken](https://support.huaweicloud.com/api-meeting/meeting_21_0027.html)"接口。
2. 使用会控Token获取Websocket建链Token。请参考"[获取WebSocket建链Token - CreateWebSocketToken](https://support.huaweicloud.com/api-meeting/meeting_21_1506.html)"接口。
3. 与服务端建立Websocket链接。
4. 订阅需要华为云会议服务端推送的信息类型。
5. 华为云会议服务端推送订阅的信息。
6. 至少在180秒内发送一次心跳消息。
#### 代码示例1：
前端WebSocket建链、订阅，收发消息代码。
```
WebSocket建链和消息收发
```
#### 代码示例2：
Java WebSocket客户端建链、收发消息代码。
```
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import org.java_websocket.WebSocket;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;
import com.google.gson.Gson;
public class WebSocketClientDemo extends WebSocketClient{
public WebSocketClientDemo(String url) throws URISyntaxException {
super(new URI(url));
}
@Override
public void onOpen(ServerHandshake shake) {
System.out.println("Hand shake!");
for(Iterator it = shake.iterateHttpFields(); it.hasNext();) {
String key = it.next();
System.out.println(key + ":" + shake.getFieldValue(key));
}
}
@Override
public void onMessage(String paramString) {
System.out.println("receive msg: " + paramString);
}
@Override
public void onClose(int paramInt, String paramString, Boolean paramBoolean) {
System.out.println("Channel close!");
}
@Override
public void onError(Exception e) {
System.out.println("error: " + e);
}
public static void main(String[] args) throws Exception{
try {
// webSocket建链
String confID = "900964776";
String tempToken = "&tmpToken=" + "获取WebSocket建链Token";
String url = "wss://100.94.23.40:443/cms/open/websocket/confctl/increment/conn?confID=" + confID
+ tempToken;
WebSocketClientDemo client = new WebSocketClientDemo(url);
client.connect();
while (!client.getReadyState().equals(WebSocket.READYSTATE.OPEN)) {
System.out.println("Not open yet");
Thread.sleep(100);
}
System.out.println("WebSocket channel connected!");
// WebSocket已连接，发送订阅消息
Gson gson = new Gson();
List subscribeTypes = new ArrayList<>();
subscribeTypes.add(SubscribeType.ConfBasicInfoNotify);
subscribeTypes.add(SubscribeType.ConfDynamicInfoNotify);
subscribeTypes.add(SubscribeType.ParticipantsNotify);
subscribeTypes.add(SubscribeType.AttendeesNotify);
subscribeTypes.add(SubscribeType.SpeakerChangeNotify);
subscribeTypes.add(SubscribeType.InviteResultNotify);
SubscribeReq subscribeReq = SubscribeReq.builder()
.subscribeType(subscribeTypes)
.confToken(获取会控Token)
.build();
SubscribeMsgFrame subscribeMsgFrame = SubscribeMsgFrame.builder()
.action("Subscribe")
.sequence("000000000000000002611382271289")
.data(gson.toJson(subscribeReq))
.build();
String jsonStr = gson.toJson(subscribeMsgFrame);
client.send(jsonStr);
} catch (URISyntaxException e) {
e.printStackTrace();
}
}
}
Java WebSocket客户端建链收发消息。
SubscribeReq.java
------
import java.util.List;
import lombok.Builder;
import lombok.Getter;
import lombok.Setter;
@Getter
@Setter
@Builder
public class SubscribeReq {
/**
* 订阅类型
*/
List subscribeType;
/**
* 会议Token
*/
String confToken;
}
SubscribeMsgFrame .java
------
import lombok.Builder;
import lombok.Getter;
import lombok.Setter;
@Getter
@Setter
@Builder
public class SubscribeMsgFrame {
/**
* 消息类型
*/
String action;
/**
* 消息随机序列号
*/
String sequence;
/**
* 消息体
*/
String data;
}
```