feat：【iot】WebSocket 连接线程安全与 JDK 8 兼容

yudao-dependencies/pom.xml

@@ -76,6 +76,8 @@
         <jimubi.version>2.3.0</jimubi.version>
         <weixin-java.version>4.7.9-20251224.161447</weixin-java.version>
         <alipay-sdk-java.version>4.40.607.ALL</alipay-sdk-java.version>
+        <!-- OkHttp -->
+        <okhttp.version>4.12.0</okhttp.version>
     </properties>
 
     <dependencyManagement>
@@ -653,6 +655,19 @@
                 <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
                 <version>${mqtt.version}</version>
             </dependency>
+
+            <!-- OkHttp -->
+            <dependency>
+                <groupId>com.squareup.okhttp3</groupId>
+                <artifactId>okhttp</artifactId>
+                <version>${okhttp.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>com.squareup.okhttp3</groupId>
+                <artifactId>mockwebserver</artifactId>
+                <version>${okhttp.version}</version>
+                <scope>test</scope>
+            </dependency>
         </dependencies>
     </dependencyManagement>
 

yudao-module-iot/yudao-module-iot-biz/pom.xml

@@ -73,6 +73,17 @@
             <artifactId>yudao-spring-boot-starter-excel</artifactId>
         </dependency>
 
+        <!-- OkHttp -->
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>okhttp</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>mockwebserver</artifactId>
+            <scope>test</scope>
+        </dependency>
+
         <!-- 消息队列相关 -->
         <!-- TODO @芋艿：临时打开 -->
         <dependency>

yudao-module-iot/yudao-module-iot-biz/src/main/java/cn/iocoder/yudao/module/iot/dal/redis/RedisKeyConstants.java

@@ -84,4 +84,12 @@ public interface RedisKeyConstants {
      */
     String SCENE_RULE_LIST = "iot:scene_rule_list";
 
+    /**
+     * WebSocket 连接分布式锁
+     * <p>
+     * KEY 格式：websocket_connect_lock:${serverUrl}
+     * 用于保证 WebSocket 重连操作的线程安全
+     */
+    String WEBSOCKET_CONNECT_LOCK = "iot:websocket_connect_lock:%s";
+
 }

yudao-module-iot/yudao-module-iot-biz/src/main/java/cn/iocoder/yudao/module/iot/dal/redis/rule/IotWebSocketLockRedisDAO.java

@@ -0,0 +1,67 @@
+package cn.iocoder.yudao.module.iot.dal.redis.rule;
+
+import jakarta.annotation.Resource;
+import org.redisson.api.RLock;
+import org.redisson.api.RedissonClient;
+import org.springframework.stereotype.Repository;
+
+import java.util.concurrent.TimeUnit;
+
+import static cn.iocoder.yudao.module.iot.dal.redis.RedisKeyConstants.WEBSOCKET_CONNECT_LOCK;
+
+/**
+ * IoT WebSocket 连接锁 Redis DAO
+ * <p>
+ * 用于保证 WebSocket 重连操作的线程安全，避免多线程同时重连导致的资源竞争
+ *
+ * @author HUIHUI
+ */
+@Repository
+public class IotWebSocketLockRedisDAO {
+
+    /**
+     * 锁等待超时时间（毫秒）
+     */
+    private static final long LOCK_WAIT_TIME_MS = 5000;
+
+    /**
+     * 锁持有超时时间（毫秒）
+     */
+    private static final long LOCK_LEASE_TIME_MS = 10000;
+
+    @Resource
+    private RedissonClient redissonClient;
+
+    /**
+     * 在分布式锁保护下执行操作
+     *
+     * @param serverUrl WebSocket 服务器地址
+     * @param runnable  需要执行的操作
+     * @throws Exception 如果获取锁超时或执行操作时发生异常
+     */
+    public void lock(String serverUrl, Runnable runnable) throws Exception {
+        String lockKey = formatKey(serverUrl);
+        RLock lock = redissonClient.getLock(lockKey);
+
+        try {
+            // 尝试获取分布式锁
+            boolean acquired = lock.tryLock(LOCK_WAIT_TIME_MS, LOCK_LEASE_TIME_MS, TimeUnit.MILLISECONDS);
+            if (!acquired) {
+                throw new RuntimeException("获取 WebSocket 连接锁超时，服务器: " + serverUrl);
+            }
+
+            // 执行操作
+            runnable.run();
+        } finally {
+            // 释放锁
+            if (lock.isHeldByCurrentThread()) {
+                lock.unlock();
+            }
+        }
+    }
+
+    private static String formatKey(String serverUrl) {
+        return String.format(WEBSOCKET_CONNECT_LOCK, serverUrl);
+    }
+
+}

yudao-module-iot/yudao-module-iot-biz/src/main/java/cn/iocoder/yudao/module/iot/service/rule/data/action/IotWebSocketDataRuleAction.java

@@ -3,8 +3,10 @@ package cn.iocoder.yudao.module.iot.service.rule.data.action;
 import cn.hutool.core.util.StrUtil;
 import cn.iocoder.yudao.module.iot.core.mq.message.IotDeviceMessage;
 import cn.iocoder.yudao.module.iot.dal.dataobject.rule.config.IotDataSinkWebSocketConfig;
+import cn.iocoder.yudao.module.iot.dal.redis.rule.IotWebSocketLockRedisDAO;
 import cn.iocoder.yudao.module.iot.enums.rule.IotDataSinkTypeEnum;
 import cn.iocoder.yudao.module.iot.service.rule.data.action.websocket.IotWebSocketClient;
+import jakarta.annotation.Resource;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Component;
 
@@ -22,6 +24,9 @@ import org.springframework.stereotype.Component;
 public class IotWebSocketDataRuleAction extends
         IotDataRuleCacheableAction<IotDataSinkWebSocketConfig, IotWebSocketClient> {
 
+    @Resource
+    private IotWebSocketLockRedisDAO webSocketLockRedisDAO;
+
     @Override
     public Integer getType() {
         return IotDataSinkTypeEnum.WEBSOCKET.getType();
@@ -62,12 +67,11 @@ public class IotWebSocketDataRuleAction extends
     protected void execute(IotDeviceMessage message, IotDataSinkWebSocketConfig config) throws Exception {
         try {
             // 1.1 获取或创建 WebSocket 客户端
-            // TODO @puhui999：需要加锁，保证必须连接上；
             IotWebSocketClient webSocketClient = getProducer(config);
-            // 1.2 检查连接状态，如果断开则重新连接
+
+            // 1.2 检查连接状态，如果断开则使用分布式锁保证重连的线程安全
             if (!webSocketClient.isConnected()) {
-                log.warn("[execute][WebSocket 连接已断开，尝试重新连接，服务器: {}]", config.getServerUrl());
-                webSocketClient.connect();
+                reconnectWithLock(webSocketClient, config);
             }
 
             // 2.1 发送消息
@@ -82,4 +86,24 @@ public class IotWebSocketDataRuleAction extends
         }
     }
 
+    /**
+     * 使用分布式锁进行重连
+     *
+     * @param webSocketClient WebSocket 客户端
+     * @param config          配置信息
+     */
+    private void reconnectWithLock(IotWebSocketClient webSocketClient, IotDataSinkWebSocketConfig config) throws Exception {
+        webSocketLockRedisDAO.lock(config.getServerUrl(), () -> {
+            // 双重检查：获取锁后再次检查连接状态，避免重复连接
+            if (!webSocketClient.isConnected()) {
+                log.warn("[reconnectWithLock][WebSocket 连接已断开，尝试重新连接，服务器: {}]", config.getServerUrl());
+                try {
+                    webSocketClient.connect();
+                } catch (Exception e) {
+                    throw new RuntimeException("WebSocket 重连失败，服务器: " + config.getServerUrl(), e);
+                }
+            }
+        });
+    }
+
 }

yudao-module-iot/yudao-module-iot-biz/src/main/java/cn/iocoder/yudao/module/iot/service/rule/data/action/websocket/IotWebSocketClient.java

@@ -4,13 +4,9 @@ import cn.iocoder.yudao.framework.common.util.json.JsonUtils;
 import cn.iocoder.yudao.module.iot.core.mq.message.IotDeviceMessage;
 import cn.iocoder.yudao.module.iot.dal.dataobject.rule.config.IotDataSinkWebSocketConfig;
 import lombok.extern.slf4j.Slf4j;
+import okhttp3.*;
 
-import java.net.URI;
-import java.net.http.HttpClient;
-import java.net.http.WebSocket;
-import java.time.Duration;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.CompletionStage;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -19,21 +15,23 @@ import java.util.concurrent.atomic.AtomicBoolean;
  * <p>
  * 负责与外部 WebSocket 服务器建立连接并发送设备消息
  * 支持 ws:// 和 wss:// 协议，支持 JSON 和 TEXT 数据格式
- * 基于 Java 11+ 内置的 java.net.http.WebSocket 实现
+ * 基于 OkHttp WebSocket 实现，兼容 JDK 8+
+ * <p>
+ * 注意：该类的线程安全由调用方（IotWebSocketDataRuleAction）通过分布式锁保证
  *
  * @author HUIHUI
  */
 @Slf4j
-public class IotWebSocketClient implements WebSocket.Listener {
+public class IotWebSocketClient {
 
     private final String serverUrl;
     private final Integer connectTimeoutMs;
     private final Integer sendTimeoutMs;
     private final String dataFormat;
 
-    private WebSocket webSocket;
+    private OkHttpClient okHttpClient;
+    private volatile WebSocket webSocket;
     private final AtomicBoolean connected = new AtomicBoolean(false);
-    private final StringBuilder messageBuffer = new StringBuilder();
 
     public IotWebSocketClient(String serverUrl, Integer connectTimeoutMs, Integer sendTimeoutMs, String dataFormat) {
         this.serverUrl = serverUrl;
@@ -44,8 +42,9 @@ public class IotWebSocketClient implements WebSocket.Listener {
 
     /**
      * 连接到 WebSocket 服务器
+     * <p>
+     * 注意：调用方需要通过分布式锁保证并发安全
      */
-    @SuppressWarnings("resource")
     public void connect() throws Exception {
         if (connected.get()) {
             log.warn("[connect][WebSocket 客户端已经连接，无需重复连接]");
@@ -53,17 +52,32 @@ public class IotWebSocketClient implements WebSocket.Listener {
         }
 
         try {
-            HttpClient httpClient = HttpClient.newBuilder()
-                    .connectTimeout(Duration.ofMillis(connectTimeoutMs))
+            // 创建 OkHttpClient
+            okHttpClient = new OkHttpClient.Builder()
+                    .connectTimeout(connectTimeoutMs, TimeUnit.MILLISECONDS)
+                    .readTimeout(sendTimeoutMs, TimeUnit.MILLISECONDS)
+                    .writeTimeout(sendTimeoutMs, TimeUnit.MILLISECONDS)
                     .build();
 
-            CompletableFuture<WebSocket> future = httpClient.newWebSocketBuilder()
-                    .connectTimeout(Duration.ofMillis(connectTimeoutMs))
-                    .buildAsync(URI.create(serverUrl), this);
+            // 创建 WebSocket 请求
+            Request request = new Request.Builder()
+                    .url(serverUrl)
+                    .build();
+
+            // 使用 CountDownLatch 等待连接完成
+            CountDownLatch connectLatch = new CountDownLatch(1);
+            AtomicBoolean connectSuccess = new AtomicBoolean(false);
+
+            // 创建 WebSocket 连接
+            webSocket = okHttpClient.newWebSocket(request, new IotWebSocketListener(connectLatch, connectSuccess));
 
             // 等待连接完成
-            webSocket = future.get(connectTimeoutMs, TimeUnit.MILLISECONDS);
-            connected.set(true);
+            boolean await = connectLatch.await(connectTimeoutMs, TimeUnit.MILLISECONDS);
+            if (!await || !connectSuccess.get()) {
+                close();
+                throw new Exception("WebSocket 连接超时或失败，服务器地址: " + serverUrl);
+            }
+
             log.info("[connect][WebSocket 客户端连接成功，服务器地址: {}]", serverUrl);
         } catch (Exception e) {
             close();
@@ -72,36 +86,6 @@ public class IotWebSocketClient implements WebSocket.Listener {
         }
     }
 
-    @Override
-    public void onOpen(WebSocket webSocket) {
-        log.debug("[onOpen][WebSocket 连接已打开]");
-        webSocket.request(1);
-    }
-
-    @Override
-    public CompletionStage<?> onText(WebSocket webSocket, CharSequence data, boolean last) {
-        messageBuffer.append(data);
-        if (last) {
-            log.debug("[onText][收到 WebSocket 消息: {}]", messageBuffer);
-            messageBuffer.setLength(0);
-        }
-        webSocket.request(1);
-        return null;
-    }
-
-    @Override
-    public CompletionStage<?> onClose(WebSocket webSocket, int statusCode, String reason) {
-        connected.set(false);
-        log.info("[onClose][WebSocket 连接已关闭，状态码: {}，原因: {}]", statusCode, reason);
-        return null;
-    }
-
-    @Override
-    public void onError(WebSocket webSocket, Throwable error) {
-        connected.set(false);
-        log.error("[onError][WebSocket 发生错误]", error);
-    }
-
     /**
      * 发送设备消息
      *
@@ -109,7 +93,8 @@ public class IotWebSocketClient implements WebSocket.Listener {
      * @throws Exception 发送异常
      */
     public void sendMessage(IotDeviceMessage message) throws Exception {
-        if (!connected.get() || webSocket == null) {
+        WebSocket ws = this.webSocket;
+        if (!connected.get() || ws == null) {
             throw new IllegalStateException("WebSocket 客户端未连接");
         }
 
@@ -121,9 +106,11 @@ public class IotWebSocketClient implements WebSocket.Listener {
                 messageData = message.toString();
             }
 
-            // 发送消息并等待完成
-            CompletableFuture<WebSocket> future = webSocket.sendText(messageData, true);
-            future.get(sendTimeoutMs, TimeUnit.MILLISECONDS);
+            // 发送消息
+            boolean success = ws.send(messageData);
+            if (!success) {
+                throw new Exception("WebSocket 发送消息失败，消息队列已满或连接已关闭");
+            }
             log.debug("[sendMessage][发送消息成功，设备 ID: {}，消息长度: {}]",
                     message.getDeviceId(), messageData.length());
         } catch (Exception e) {
@@ -136,18 +123,17 @@ public class IotWebSocketClient implements WebSocket.Listener {
      * 关闭连接
      */
     public void close() {
-        if (!connected.get() && webSocket == null) {
-            return;
-        }
-
         try {
             if (webSocket != null) {
-                webSocket.sendClose(WebSocket.NORMAL_CLOSURE, "客户端主动关闭")
-                        .orTimeout(5, TimeUnit.SECONDS)
-                        .exceptionally(e -> {
-                            log.warn("[close][发送关闭帧失败]", e);
-                            return null;
-                        });
+                // 发送正常关闭帧，状态码 1000 表示正常关闭
+                webSocket.close(1000, "客户端主动关闭");
+                webSocket = null;
+            }
+            if (okHttpClient != null) {
+                // 关闭连接池和调度器
+                okHttpClient.dispatcher().executorService().shutdown();
+                okHttpClient.connectionPool().evictAll();
+                okHttpClient = null;
             }
             connected.set(false);
             log.info("[close][WebSocket 客户端连接已关闭，服务器地址: {}]", serverUrl);
@@ -174,4 +160,50 @@ public class IotWebSocketClient implements WebSocket.Listener {
                 '}';
     }
 
+    /**
+     * OkHttp WebSocket 监听器
+     */
+    private class IotWebSocketListener extends WebSocketListener {
+
+        private final CountDownLatch connectLatch;
+        private final AtomicBoolean connectSuccess;
+
+        public IotWebSocketListener(CountDownLatch connectLatch, AtomicBoolean connectSuccess) {
+            this.connectLatch = connectLatch;
+            this.connectSuccess = connectSuccess;
+        }
+
+        @Override
+        public void onOpen(WebSocket webSocket, Response response) {
+            connected.set(true);
+            connectSuccess.set(true);
+            connectLatch.countDown();
+            log.info("[onOpen][WebSocket 连接已打开，服务器: {}]", serverUrl);
+        }
+
+        @Override
+        public void onMessage(WebSocket webSocket, String text) {
+            log.debug("[onMessage][收到消息: {}]", text);
+        }
+
+        @Override
+        public void onClosing(WebSocket webSocket, int code, String reason) {
+            connected.set(false);
+            log.info("[onClosing][WebSocket 正在关闭，code: {}, reason: {}]", code, reason);
+        }
+
+        @Override
+        public void onClosed(WebSocket webSocket, int code, String reason) {
+            connected.set(false);
+            log.info("[onClosed][WebSocket 已关闭，code: {}, reason: {}]", code, reason);
+        }
+
+        @Override
+        public void onFailure(WebSocket webSocket, Throwable t, Response response) {
+            connected.set(false);
+            connectLatch.countDown(); // 确保连接失败时也释放等待
+            log.error("[onFailure][WebSocket 连接失败]", t);
+        }
+    }
+
 }

yudao-module-iot/yudao-module-iot-biz/src/test/java/cn/iocoder/yudao/module/iot/service/rule/data/action/websocket/IotWebSocketClientTest.java

@@ -0,0 +1,257 @@
+package cn.iocoder.yudao.module.iot.service.rule.data.action.websocket;
+
+import cn.iocoder.yudao.module.iot.core.mq.message.IotDeviceMessage;
+import okhttp3.Response;
+import okhttp3.WebSocket;
+import okhttp3.WebSocketListener;
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * {@link IotWebSocketClient} 的单元测试
+ *
+ * @author HUIHUI
+ */
+class IotWebSocketClientTest {
+
+    private MockWebServer mockWebServer;
+
+    @BeforeEach
+    public void setUp() throws Exception {
+        mockWebServer = new MockWebServer();
+        mockWebServer.start();
+    }
+
+    @AfterEach
+    public void tearDown() throws Exception {
+        if (mockWebServer != null) {
+            mockWebServer.shutdown();
+        }
+    }
+
+    /**
+     * 简单的 WebSocket 监听器，用于测试
+     */
+    private static class TestWebSocketListener extends WebSocketListener {
+        @Override
+        public void onOpen(@NotNull WebSocket webSocket, @NotNull Response response) {
+            // 连接打开
+        }
+
+        @Override
+        public void onMessage(@NotNull WebSocket webSocket, @NotNull String text) {
+            // 收到消息
+        }
+
+        @Override
+        public void onClosing(@NotNull WebSocket webSocket, int code, @NotNull String reason) {
+            webSocket.close(code, reason);
+        }
+
+        @Override
+        public void onFailure(@NotNull WebSocket webSocket, @NotNull Throwable t, @Nullable Response response) {
+            // 连接失败
+        }
+    }
+
+    @Test
+    public void testConstructor_defaultValues() {
+        // 准备参数
+        String serverUrl = "ws://localhost:8080";
+
+        // 调用
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, null, null, null);
+
+        // 断言：验证默认值被正确设置
+        assertNotNull(client);
+        assertFalse(client.isConnected());
+    }
+
+    @Test
+    public void testConstructor_customValues() {
+        // 准备参数
+        String serverUrl = "ws://localhost:8080";
+        Integer connectTimeoutMs = 3000;
+        Integer sendTimeoutMs = 5000;
+        String dataFormat = "TEXT";
+
+        // 调用
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, connectTimeoutMs, sendTimeoutMs, dataFormat);
+
+        // 断言
+        assertNotNull(client);
+        assertFalse(client.isConnected());
+    }
+
+    @Test
+    public void testConnect_success() throws Exception {
+        // 准备参数：使用 MockWebServer 的 WebSocket 端点
+        String serverUrl = "ws://" + mockWebServer.getHostName() + ":" + mockWebServer.getPort();
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        // mock：设置 MockWebServer 响应 WebSocket 升级请求
+        mockWebServer.enqueue(new MockResponse().withWebSocketUpgrade(new TestWebSocketListener()));
+
+        // 调用
+        client.connect();
+
+        // 断言
+        assertTrue(client.isConnected());
+
+        // 清理
+        client.close();
+    }
+
+    @Test
+    public void testConnect_alreadyConnected() throws Exception {
+        // 准备参数
+        String serverUrl = "ws://" + mockWebServer.getHostName() + ":" + mockWebServer.getPort();
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        // mock
+        mockWebServer.enqueue(new MockResponse().withWebSocketUpgrade(new TestWebSocketListener()));
+
+        // 调用：第一次连接
+        client.connect();
+        assertTrue(client.isConnected());
+
+        // 调用：第二次连接（应该不会重复连接）
+        client.connect();
+        assertTrue(client.isConnected());
+
+        // 清理
+        client.close();
+    }
+
+    @Test
+    public void testSendMessage_success() throws Exception {
+        // 准备参数
+        String serverUrl = "ws://" + mockWebServer.getHostName() + ":" + mockWebServer.getPort();
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        IotDeviceMessage message = IotDeviceMessage.builder()
+                .deviceId(123L)
+                .method("thing.property.report")
+                .params("{\"temperature\": 25.5}")
+                .build();
+
+        // mock
+        mockWebServer.enqueue(new MockResponse().withWebSocketUpgrade(new TestWebSocketListener()));
+
+        // 调用
+        client.connect();
+        client.sendMessage(message);
+
+        // 断言：消息发送成功不抛异常
+        assertTrue(client.isConnected());
+
+        // 清理
+        client.close();
+    }
+
+    @Test
+    public void testSendMessage_notConnected() {
+        // 准备参数
+        String serverUrl = "ws://localhost:8080";
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        IotDeviceMessage message = IotDeviceMessage.builder()
+                .deviceId(123L)
+                .method("thing.property.report")
+                .params("{\"temperature\": 25.5}")
+                .build();
+
+        // 调用 & 断言：未连接时发送消息应抛出异常
+        assertThrows(IllegalStateException.class, () -> client.sendMessage(message));
+    }
+
+    @Test
+    public void testClose_success() throws Exception {
+        // 准备参数
+        String serverUrl = "ws://" + mockWebServer.getHostName() + ":" + mockWebServer.getPort();
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        // mock
+        mockWebServer.enqueue(new MockResponse().withWebSocketUpgrade(new TestWebSocketListener()));
+
+        // 调用
+        client.connect();
+        assertTrue(client.isConnected());
+
+        client.close();
+
+        // 断言
+        assertFalse(client.isConnected());
+    }
+
+    @Test
+    public void testClose_notConnected() {
+        // 准备参数
+        String serverUrl = "ws://localhost:8080";
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        // 调用：关闭未连接的客户端不应抛异常
+        assertDoesNotThrow(client::close);
+        assertFalse(client.isConnected());
+    }
+
+    @Test
+    public void testIsConnected_initialState() {
+        // 准备参数
+        String serverUrl = "ws://localhost:8080";
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        // 断言：初始状态应为未连接
+        assertFalse(client.isConnected());
+    }
+
+    @Test
+    public void testToString() {
+        // 准备参数
+        String serverUrl = "ws://localhost:8080";
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "JSON");
+
+        // 调用
+        String result = client.toString();
+
+        // 断言
+        assertNotNull(result);
+        assertTrue(result.contains("serverUrl='ws://localhost:8080'"));
+        assertTrue(result.contains("dataFormat='JSON'"));
+        assertTrue(result.contains("connected=false"));
+    }
+
+    @Test
+    public void testSendMessage_textFormat() throws Exception {
+        // 准备参数
+        String serverUrl = "ws://" + mockWebServer.getHostName() + ":" + mockWebServer.getPort();
+        IotWebSocketClient client = new IotWebSocketClient(serverUrl, 5000, 5000, "TEXT");
+
+        IotDeviceMessage message = IotDeviceMessage.builder()
+                .deviceId(123L)
+                .method("thing.property.report")
+                .params("{\"temperature\": 25.5}")
+                .build();
+
+        // mock
+        mockWebServer.enqueue(new MockResponse().withWebSocketUpgrade(new TestWebSocketListener()));
+
+        // 调用
+        client.connect();
+        client.sendMessage(message);
+
+        // 断言：消息发送成功不抛异常
+        assertTrue(client.isConnected());
+
+        // 清理
+        client.close();
+    }
+
+}