• Springboot2.7集成websocket及相关问题

    1、集成websocket完整代码

    导入maven依赖

    1. <dependency>
    2.     <groupId>org.springframework.bootgroupId>
    3.     <artifactId>spring-boot-starter-websocketartifactId>
    4. dependency>

    服务端代码

    1. （1）注入bean
    2. @Configuration
    3. @EnableWebSocket
    4. public class WebSocketConfig {
    5.     @Bean
    6.     public ServerEndpointExporter serverEndpointExporter() {
    7.         return new ServerEndpointExporter();
    8.     }
    9. }
    10. （2）服务端开放的服务及其业务逻辑
    11. @Slf4j
    12. @Component
    13. @ServerEndpoint("/testcase/page/{clientId}")
    14. //@Lazy
    15. public class WsMessageService {
    16.  
    17.     //与某个客户端的连接会话
    18.     private Session session;
    19.  
    20.     //存放每个客户端对应的WebSocket对象。
    21.     private static Map webSocketsBeanMap = new ConcurrentHashMap<>();
    22.  
    23.     //每次连接都是一个新的会话对象，线程安全的
    24.     String userId;
    25.  
    26.     //注入业务类。要注意setTestcaseService()的名称不能错，set后的字符串要和要注入的变量名一致。
    27.     private static TestcaseService testcaseService;
    28.     @Autowired
    29.     public void setTestcaseService(TestcaseService testcaseService) {
    30.         WsMessageService.testcaseService= testcaseService;
    31.     }
    32.  
    33.     //private TestcaseService testcaseService = SpringContextUtil.getBean(TestcaseService.class);
    34.  
    35.     @OnOpen
    36.     public void onOpen(Session session, @PathParam(value = "clientId") String userId) {
    37.         this.session = session;
    38.         this.userId = userId;
    39.         webSocketsBeanMap.put(userId, this);
    40.         log.info("OnOpen连接成功，userId：{}，当前在线人数：{}", userId, this.getOnLineCount());
    41.     }
    42.  
    43.     @OnMessage
    44.     public void onMessage(String message) throws IOException {
    45.         Session session = webSocketsBeanMap.get(this.userId).session;
    46.         if (session==null || !session.isOpen()) {
    47.             return;
    48.         }
    49.         log.info("收到客户端的消息:" + message);
    50.         //start业务
    51.         Integer pageNum = null;
    52.         Integer pageSize = null;
    53.         String pid = null;
    54.         String vid = null;
    55.         if (session.getRequestParameterMap().get("pageNum")!= null) {
    56.             pageNum = Integer.valueOf(session.getRequestParameterMap().get("pageNum").get(0));
    57.         }
    58.         if (session.getRequestParameterMap().get("pageNum")!= null) {
    59.             pageSize = Integer.valueOf(session.getRequestParameterMap().get("pageSize").get(0));
    60.         }
    61.         if (session.getRequestParameterMap().get("pid")!= null) {
    62.             pid = session.getRequestParameterMap().get("pid").get(0);
    63.         }
    64.         if (session.getRequestParameterMap().get("vid")!= null) {
    65.             vid = session.getRequestParameterMap().get("vid").get(0);
    66.         }
    67.         PageInfo pageInfo = testcaseService.findTestcaseByMultiCondition(pageNum, pageSize, pid, vid);
    68.         //end业务
    69.         try {
    70.             JSONObject object = new JSONObject();
    71.             object.put("data", pageInfo);
    72.             object.put("code", 200);
    73.             object.put("message", "SUCCESS");
    74.             this.session.getBasicRemote().sendText(String.valueOf(object.toString()));
    75.         } catch (IOException e) {
    76.             throw new RuntimeException(e);
    77.         }
    78.     }
    79.  
    80.     @OnClose
    81.     public void onClose() throws IOException {
    82.         log.info("会话关闭，关闭会话的用户Id为：{}", this.userId);
    83.         webSocketsBeanMap.remove(this.userId);
    84.         log.info("当前在线人数：{}", this.getOnLineCount());
    85.     }
    86.  
    87.     @OnError
    88.     public void onError(Session session, Throwable error) {
    89.         log.error("连接错误：" + error.getMessage());
    90.         error.printStackTrace();
    91.     }
    92.  
    93.     private int getOnLineCount() {
    94.         return webSocketsBeanMap.size();
    95.     }
    96. }

    测试服务端的可用性。在浏览器的控制台输入以下代码可以测试。

    1. function initWebSocket(wsUri) {
    2.             var websocket = new WebSocket(wsUri);
    3.             websocket.onopen = function(evt) {
    4.                 console.log('连接建立中... '+wsUri);
    5.             };
    6.             websocket.onclose = function(evt) {
    7.                 console.log('连接关闭中...', evt);
    8.             };
    9.             websocket.onmessage = function(evt) {
    10.                 console.log('收到来自服务端的消息：', evt.data);
    11.             };
    12.             websocket.onerror = function(evt) {
    13.                 console.log('发生错误...', evt);
    14.             };
    15.             return websocket;
    16.         }
    17.     var websocket = initWebSocket("ws://ip:port/testcase/page/123?pid=5922cc3d03f74012a7112c931c8497d7&vid=fc2d7a6049ff4c7bafc40bf659b4e903");
    18.         var msg, i = 0;
    19.         var loop = setInterval(function(){
    20.             msg = "Hello " +(i++);
    21.             if(websocket.readyState == WebSocket.OPEN) {
    22.                 websocket.send(msg);
    23.                 console.log('已发送消息：' +msg);
    24.             } else{
    25.                 clearInterval(loop);
    26.                 console.log('连接已关闭');
    27.             }
    28.         }, 10000);

    2、集成websocket另一种方法（用控制台测试时返回的数据会乱码）

    代码找不到了。但那种方法有一个特征就是使用的注解比当前的方法少。

    3、解决业务类注入不进去的问题（两种方法，推荐第一种）

    （1）第一种：就是当前使用的注入方法。注意命名，否则不会注入成功

    1. //注入业务类。要注意setTestcaseService()的名称不能错，set后的字符串要和要注入的变量名一致。
    2.     private static TestcaseService testcaseService;
    3.     @Autowired
    4.     public void setTestcaseService(TestcaseService testcaseService) {
    5.         WsMessageService.testcaseService= testcaseService;
    6.     }

    （2）第二种：自己写一个SpringContextUtil工具类，协助注入

    1. package cn.xxxxx.tmMaster.utils;
    2.  
    3. import lombok.extern.slf4j.Slf4j;
    4. import org.mybatis.logging.LoggerFactory;
    5. import org.springframework.beans.BeansException;
    6. import org.springframework.context.ApplicationContext;
    7. import org.springframework.context.ApplicationContextAware;
    8. import org.springframework.stereotype.Component;
    9.  
    10. import java.util.logging.Logger;
    11.  
    12. @Slf4j
    13. @Component
    14. public class SpringContextUtil implements ApplicationContextAware {
    15.  
    16.     private static ApplicationContext applicationContext;
    17.  
    18.     @Override
    19.     public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    20.         SpringContextUtil.applicationContext = applicationContext;
    21.     }
    22.  
    23.     /**
    24.      * 获取 applicationContext
    25.      */
    26.     public static ApplicationContext getApplicationContext() {
    27.         return applicationContext;
    28.     }
    29.  
    30.     /**
    31.      * 通过 name 获取 bean 对象
    32.      */
    33.     public static Object getBean(String name) {
    34.  
    35.         return getApplicationContext().getBean(name);
    36.     }
    37.  
    38.     /**
    39.      * 通过 class 获取 bean 对象
    40.      */
    41.     public static  T getBean(Class clazz) {
    42.         return getApplicationContext().getBean(clazz);
    43.     }
    44.  
    45.     /**
    46.      * 通过 name，clazz  获取指定的 bean 对象
    47.      */
    48.     public static  T getBean(String name, Class clazz) {
    49.         return getApplicationContext().getBean(name, clazz);
    50.     }
    51. }

    在WsMessageService中使用如下代码注入进去，但在类上必须要@Lazy进行懒加载，否则会报错

    1. @Lazy
    2. public class WsMessageService {
    3. ……
    4.     private TestcaseService testcaseService = SpringContextUtil.getBean(TestcaseService.class);
    5. ……
    6. }

    不加@Lazy报错如下：org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'wsMessageService' defined in file [D:\javaworkspace\test-xxxx\tm-master\target\classes\cn\xxxxx\tmMaster\service\testcase\WsMessageService.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [cn.xxxxx.tmMaster.service.testcase.WsMessageService]: Constructor threw exception; nested exception is java.lang.NullPointerException

    1. org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'wsMessageService' defined in file [D:\javaworkspace\test-xxxx\tm-master\target\classes\cn\xxxxx\tmMaster\service\testcase\WsMessageService.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [cn.xxxxx.tmMaster.service.testcase.WsMessageService]: Constructor threw exception; nested exception is java.lang.NullPointerException
    2.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1334) ~[spring-beans-5.3.29.jar:5.3.29]
    3.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1232) ~[spring-beans-5.3.29.jar:5.3.29]
    4.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.29.jar:5.3.29]
    5.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.29.jar:5.3.29]
    6.     at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.29.jar:5.3.29]
    7.     at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.29.jar:5.3.29]
    8.     at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.29.jar:5.3.29]
    9.     at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.29.jar:5.3.29]
    10.     at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955) ~[spring-beans-5.3.29.jar:5.3.29]
    11.     at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:921) ~[spring-context-5.3.29.jar:5.3.29]
    12.     at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.29.jar:5.3.29]
    13.     at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.14.jar:2.7.14]
    14.     at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:731) [spring-boot-2.7.14.jar:2.7.14]
    15.     at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) [spring-boot-2.7.14.jar:2.7.14]
    16.     at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-2.7.14.jar:2.7.14]
    17.     at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303) [spring-boot-2.7.14.jar:2.7.14]
    18.     at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292) [spring-boot-2.7.14.jar:2.7.14]
    19.     at cn.xxxxx.tmMaster.MasterApplication.main(MasterApplication.java:17) [classes/:na]
    20.     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_382]
    21.     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_382]
    22.     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_382]
    23.     at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_382]
    24.     at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:50) [spring-boot-devtools-2.7.14.jar:2.7.14]
    25. Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [cn.xxxxx.tmMaster.service.testcase.WsMessageService]: Constructor threw exception; nested exception is java.lang.NullPointerException
    26.     at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:224) ~[spring-beans-5.3.29.jar:5.3.29]
    27.     at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87) ~[spring-beans-5.3.29.jar:5.3.29]
    28.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1326) ~[spring-beans-5.3.29.jar:5.3.29]
    29.     ... 22 common frames omitted
    30. Caused by: java.lang.NullPointerException: null
    31.     at cn.xxxxx.tmMaster.utils.SpringContextUtil.getBean(SpringContextUtil.java:55) ~[classes/:na]
    32.     at cn.xxxxx.tmMaster.service.testcase.WsMessageService.(WsMessageService.java:48) ~[classes/:na]
    33.     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_382]
    34.     at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_382]
    35.     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_382]
    36.     at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_382]
    37.     at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:211) ~[spring-beans-5.3.29.jar:5.3.29]
    38.     ... 24 common frames omitted

    参考资料：

    SpringBoot集成WebSocket实现客户端与服务端长连接通信_springboot实现websocket客户端_拄杖忙学轻声码的博客-CSDN博客 SpringBoot集成WebSocket实现客户端与服务端长连接通信

    快速搭建springboot websocket客户端_springboot实现websocket客户端_wcybaonier的博客-CSDN博客 快速搭建springboot websocket客户端

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  • 原文地址：https://blog.csdn.net/qq_30719815/article/details/132907229