WebSocket 是一种在客户端和服务器之间提供低延迟、全双工通信的网络协议。它允许双方在建立一次连接后，进行实时、持续的数据交换，无需像HTTP那样为每一个请求和响应建立新的连接。WebSocket的设计初衷是解决传统HTTP协议在实时通信方面的不足，比如实现实时聊天、游戏、股票报价等需要高频率、连续数据更新的应用场景。
1 构建服务端
1.1 引入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
1.2 创建配置类
@Slf4j
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
1.3 创建服务端
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArraySet;
@Component
@Slf4j
@ServerEndpoint("/websocket/{userId}")
public class WebSocketTest {
/**
* 线程安全的无序的集合
*/
private static final CopyOnWriteArraySet<Session> SESSIONS = new CopyOnWriteArraySet<>();
/**
* 存储在线连接数
*/
private static final Map<String, Session> SESSION_POOL = new HashMap<>();
@OnOpen
public void onOpen(Session session, @PathParam(value = "userId") String userId) {
try {
SESSIONS.add(session);
SESSION_POOL.put(userId, session);
log.info("【WebSocket消息】有新的连接，总数为：" + SESSIONS.size());
} catch (Exception e) {
e.printStackTrace();
}
}
@OnClose
public void onClose(Session session) {
try {
SESSIONS.remove(session);
log.info("【WebSocket消息】连接断开，总数为：" + SESSIONS.size());
} catch (Exception e) {
e.printStackTrace();
}
}
@OnMessage
public void onMessage(String message) {
log.info("【WebSocket消息】收到客户端消息：" + message);
Session session = SESSION_POOL.get("123");
if (session != null && session.isOpen()) {
try {
synchronized (session) {
log.info("【WebSocket消息】单点消息：" + message);
session.getAsyncRemote().sendText(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 此为广播消息
*
* @param message 消息
*/
public void sendAllMessage(String message) {
log.info("【WebSocket消息】广播消息：" + message);
for (Session session : SESSIONS) {
try {
if (session.isOpen()) {
session.getAsyncRemote().sendText(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 此为单点消息
*
* @param userId 用户编号
* @param message 消息
*/
public void sendOneMessage(String userId, String message) {
Session session = SESSION_POOL.get(userId);
if (session != null && session.isOpen()) {
try {
synchronized (session) {
log.info("【WebSocket消息】单点消息：" + message);
session.getAsyncRemote().sendText(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 此为单点消息(多人)
*
* @param userIds 用户编号列表
* @param message 消息
*/
public void sendMoreMessage(String[] userIds, String message) {
for (String userId : userIds) {
Session session = SESSION_POOL.get(userId);
if (session != null && session.isOpen()) {
try {
log.info("【WebSocket消息】单点消息：" + message);
session.getAsyncRemote().sendText(message);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
2 创建客户端
2.1 引入依赖
<dependency>
<groupId>org.java-websocket</groupId>
<artifactId>Java-WebSocket</artifactId>
<version>1.5.3</version>
</dependency>
2.2 注入对象
在配置类中注入WebSocketClient
import lombok.extern.slf4j.Slf4j;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
import java.net.URI;
@Slf4j
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
@Bean
public WebSocketClient webSocketClient() {
WebSocketClient wsc = null;
try {
wsc = new WebSocketClient(new URI("ws://127.0.0.1:2580/websocket/123")) {
@Override
public void onOpen(ServerHandshake serverHandshake) {
log.info("与服务端建立连接");
}
@Override
public void onMessage(String s) {
log.info("收到服务端的消息：{}", s);
}
@Override
public void onClose(int i, String s, boolean b) {
log.info("与服务端的连接断开 code:{} reason:{} {}", i, s, b);
}
@Override
public void one rror(Exception e) {
log.info("连接报错");
}
};
wsc.connect();
return wsc;
} catch (Exception e) {
e.printStackTrace();
}
return wsc;
}
}
2.3 测试
import org.java_websocket.client.WebSocketClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
public class TestController {
@Resource
WebSocketClient wsClient;
@GetMapping("/send")
public void test(String text){
wsClient.send(text);
}
}
2.4 结果
浏览器访问
http://localhost:2580/send?text=测试
结果
2024-07-06 15:38:28.586 INFO 25860 --- [nio-2580-exec-4] c.x.p.websocket.socket.WebSocketTest : 【WebSocket消息】收到客户端消息：测试
2024-07-06 15:38:28.586 INFO 25860 --- [nio-2580-exec-4] c.x.p.websocket.socket.WebSocketTest : 【WebSocket消息】单点消息：测试
2024-07-06 15:38:28.587 INFO 25860 --- [ctReadThread-31] c.x.p.websocket.config.WebSocketConfig : 收到服务端的消息：测试
