springboot整合websocket

1.创建springboot项目，引入spring-boot-starter-websocket依赖

   <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

全部依赖如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.10</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.cherry</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
<!--        // springboot整合websocket-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

2.创建一个TextWebSocketHandler的子类，重写handleTextMessage、afterConnectionEstablished、afterConnectionClosed方法

handleTextMessage()

handleTextMessage()方法通过英文方法名可知，用于处理文本信息。它有两个参数分别是：WebSocketSession和TextMessage。WebSocketSession可以通过sendMessage将消息发送给前台。TextMessage通过调用getPayload（）接收前台消息体。

afterConnectionEstablished()

afterConnectionEstablished方法通过英文方法名可知，用于连接确立之后。
通过WebSocketSession的sendMessage方法，将创建的TextMessage对象给前台。

afterConnectionClosed

afterConnectionClosed方法用于连接关闭之后。参数有WebSocketSession和CloseStatus。WebSocketSession的方法sendMessage可以向前台发送消息，CloseStatus的getReason方法获得关闭的原因。

package com.cherry.demo.handler;

import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

import java.io.IOException;

@Component
public class MyHandler extends TextWebSocketHandler {

    // 客户端想服务器发消息
    @Override
    public void handleTextMessage(WebSocketSession session, TextMessage message)
            throws IOException {
        // 接收客户端的消息  message.getPayload()消息体
        System.out.println("获取到消息 >> " + message.getPayload());
        session.sendMessage(new TextMessage("消息已收到"));
        // 向服务端发送消息
        if(message.getPayload().equals("10")){
            for (int i = 0; i < 10; i++) {
                session.sendMessage(new TextMessage("消息 -> " + i));
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    // 建议连接时
    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws
            Exception {
        session.sendMessage(new TextMessage("欢迎连接到ws服务"));
    }

    // 关闭连接
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status)
            throws Exception {
        System.out.println("断开连接！");
    }
}

3.创建WebSocketConfigurer接口的子类，重写registerWebSocketHandlers方法。

registerWebSocketHandlers()方法参数是WebSocketHandlerRegistry 。调用WebSocketHandlerRegistry 的addHandler方法传递处理器和路径。处理器参数是上一步创建的TextWebSocketHandler 的子类。路径是客户端调用时跟在端口后的路径。再调用WebSocketHandlerRegistry 的setAllowedOrigins方法传递星号，允许跨域访问。

WebSocketHandlerRegistry

addHandler()方法第一个传输传递处理器，第一个参数传递路径
setAllowedOrigins()方法设置允许源，传递星号，否则跨域。

import com.cherry.demo.handler.MyHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
    @Autowired
    private MyHandler myHandler;

    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(this.myHandler, "/ws").setAllowedOrigins("*");
    }

}

4.使用easyswoole在线工具，测试websocket功能

http://www.easyswoole.com/wstool.html