websocket推送消息
websocket是一种双向通信协议，HTTP是单向的。
直接上代码：
1.首先创建一个要整合websocket的springboot模块
本文讲解主要使用的类：
配置文件：
server:
port: 1013
spring:
application:
name: IDEAL-WEBSOCKET
2.添加依赖
推荐idea在线创建springboot模块或者https://start.spring.io/。
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>demo</artifactId>
<groupId>com.example</groupId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>ideal-websocket-1013</artifactId>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- websocket的基本依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.73</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-commons</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
3.本项目演示的是根据用户id推送给不同的客户端：实际场景中，一个账号可能支持多人同时登陆，每个登陆人员的客户端界面都要显示该用户的即时业务信息
创建一个用户DTO；
package com.demo.websocket.dto;
import com.alibaba.fastjson.JSONObject;
import lombok.Data;
@Data
public class UserDto {
private String userId;
private String userName;
@Override
public String toString () {
return JSONObject.toJSONString(this);
}
}
4.编写websocet服务：url是/show/user/peoples，这个是给前端调用的
前端调用时候可以用websocket在线测试网址：地址：ws://127.0.0.1:1013/show/user/peoples，具体的后面会截图演示。
package com.demo.websocket.websocket;
import com.alibaba.fastjson.JSON;
import com.demo.websocket.config.WebSocketConfig;
import com.demo.websocket.dto.UserDto;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
@Slf4j
@Component
@ServerEndpoint(value = "/show/user/peoples")
public class UserWebSocket {
private static Map<String, List<Session>> clients = new ConcurrentHashMap<>();
@OnOpen
public void onOpen(Session session) {
log.info("有新的客户端上线: {}", session.getId());
List<Session> list = new CopyOnWriteArrayList<>();
list.add(session);
clients.put(session.getId(), list);
}
@OnClose
public void onClose(Session session) {
String sessionId = session.getId();
log.info("有客户端离线: {}", sessionId);
clients.remove(sessionId);
}
@OnError
public void onError(Session session, Throwable throwable) {
throwable.printStackTrace();
if (clients.get(session.getId()) != null) {
clients.remove(session.getId());
}
}
@OnMessage
public void onMessage(String message, Session session){
UserDto userDto = JSON.parseObject(message, UserDto.class);
List<Session> list = clients.get(userDto.getUserId());
if(null == list){
list = new CopyOnWriteArrayList<Session>();
list.add(session);
}else {
list.add(session);
}
clients.put(userDto.getUserId(),list);
log.info("用户新的客户端加入成功");
}
/**
* 发送消息
*
* @param userDto 消息对象
*/
public void sendToUser(UserDto userDto) {
List<Session> list = clients.get(userDto.getUserId());
if(null != list){
log.info("需要发送的消息个数==={}",list.size());
for(Session session : list){
try {
session.getBasicRemote().sendText(userDto.toString());
}catch (IOException e){
log.error("发送websocket消息失败：{}", e);
}
}
}
}
}
4.测试接口：WebSocketController
package com.demo.websocket.controller;
import com.alibaba.fastjson.JSONObject;
import com.demo.websocket.dto.UserDto;
import com.demo.websocket.websocket.OneToManyWebSocket;
import com.demo.websocket.websocket.OneToOneWebSocket;
import com.demo.websocket.websocket.UserWebSocket;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.HashMap;
import java.util.Map;
@RestController
@Slf4j
@RequestMapping("")
public class WebSocketController {
@Autowired
private UserWebSocket userWebSocket;
/**
* 模拟给同一个用户的不同客户段发送消息
* @return
*/
@PostMapping(value = "/send/user")
String sendUser(@RequestBody UserDto userDto){
log.info("开始给用户发送消息");
userWebSocket.sendToUser(userDto);
return "成功";
}
}
5.为了方便测试，模块中引入了swagger2的配置
SwaggerConfig类：
package com.demo.websocket.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
/**
* Description：swagger2配置类
* @Date 2019-04-29 00:05
*/
@Configuration
public class SwaggerConfig {
@Bean
public Docket myDocket() {
Docket docket = new Docket(DocumentationType.SWAGGER_2);
ApiInfo apiInfo = new ApiInfoBuilder()
.title("websocket---Api接口文档") // 标题
.description("websocket学习") // 描述
.contact(new Contact("", "", ""))
.version("1.0") // 版本号
.build();
docket.apiInfo(apiInfo);
//设置只生成被Api这个注解注解过的Ctrl类中有ApiOperation注解的api接口的文档
docket.select()
.apis(RequestHandlerSelectors.basePackage("com.demo.websocket.controller"))
.paths(PathSelectors.any())
.build();
return docket;
}
}
SwaggerAddressConfig类：
package com.demo.websocket.config;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.web.context.WebServerInitializedEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.UnknownHostException;
/**
* @Date ：2019/9/9 10:41
* @Description：控制台输出 Swagger 接口文档地址
*/
@Slf4j
@Component
public class SwaggerAddressConfig implements ApplicationListener<WebServerInitializedEvent> {
private int serverPort;
public int getPort(){
return this.serverPort;
}
@Override
public void onApplicationEvent(WebServerInitializedEvent webServerInitializedEvent) {
try {
InetAddress localHost = Inet4Address.getLocalHost();
this.serverPort = webServerInitializedEvent.getWebServer().getPort();
log.info("启动完成，接口文档地址：http://"+localHost.getHostAddress()+":"+serverPort+"/swagger-ui.html");
} catch (UnknownHostException e) {
log.info("获取本机的ip异常错误=={}",e);
}
}
}
WebSocketApplication模块启动类：添加上@EnableSwagger2
package com.demo.websocket;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
@EnableDiscoveryClient // 除了eureka，还可以注册到其它的注册中心，如zookeeper上；
@SpringBootApplication
@EnableSwagger2
public class WebSocketApplication {
public static void main(String[] args) {
SpringApplication.run(WebSocketApplication.class,args);
}
}
启动项目以后：访问图片中红圈内的地址就能打开swagger页面
6.效果展示
如下图：打开http://www.websocket-test.com/在线测试的网址，可能会被浏览器安全拦截，选择继续访问。
websocket连接地址：ws://127.0.0.1:1013/show/user/peoples
然后在发送的内容中发送一条用户body：表示用户111的某个客户端上线。
{
"userId": "111",
"userName": "bbb"
}
模拟用户111的客户端1：
模拟用户111的客户端2：
模拟用户222的客户端：
接下来模拟后台数据变动给前端推送消息：
测试接口的调用使用swagger进行，关于swagger的具体使用，可以自行百度；没有的直接用postman或者jmeter都行。
将userId的值在"111"和"222"间切换，就能看到在websocket线测试网页右边显示出对应的消息了。如果userId=“111”,就只在”111“的页面显示发送的消息，如果userId=“222”,就只在”222“的页面显示发送的消息。
到此就演示结束了
