Java Spring WebSocket实现后端消息主动推送

最新推荐文章于 2025-03-16 21:00:21 发布

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本文详细介绍了如何使用Java Spring构建WebSocket消息推送Demo。首先，通过maven配置相关依赖，然后创建WebSocket处理类SocketHandler、配置类WebSocketConfig以及拦截器WebSocketInterceptor。在WebSocketConfig中注册处理类和拦截器，WebSocketInterceptor用于将HttpSession中的对象放入WebSocketSession中，SocketHandler负责处理WebSocket连接和消息。最后，展示了SpringMVC Controller类如何与WebSocket交互，实现后端消息向特定用户或所有用户的推送。

这篇文章将介绍如何构建一个简单的WebSocket消息推送Demo

使用eclipse建立maven项目后引入相关的依赖jar包，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 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.accenture</groupId>
<artifactId>webSocket</artifactId>
<name>webSocket</name>
<packaging>war</packaging>
<version>1.0.0-BUILD-SNAPSHOT</version>
<properties>
<java-version>1.6</java-version>
<org.aspectj-version>1.6.10</org.aspectj-version>
<org.slf4j-version>1.6.6</org.slf4j-version>
<spring-framework.version>4.1.6.RELEASE</spring-framework.version>
<junit.version>4.11</junit.version>
<jackson.version>2.6.0</jackson.version>
</properties>
<dependencies>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring-framework.version}</version>
<exclusions>

<exclusion>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-expression</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring-framework.version}</version>
</dependency>


<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>${spring-framework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>${spring-framework.version}</version>
</dependency>


<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>${jackson.version}</version>
</dependency>


<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${org.aspectj-version}</version>
</dependency>


<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${org.slf4j-version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>${org.slf4j-version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${org.slf4j-version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.15</version>
<exclusions>
<exclusion>
<groupId>javax.mail</groupId>
<artifactId>mail</artifactId>
</exclusion>
<exclusion>
<groupId>javax.jms</groupId>
<artifactId>jms</artifactId>
</exclusion>
<exclusion>
<groupId>com.sun.jdmk</groupId>
<artifactId>jmxtools</artifactId>
</exclusion>
<exclusion>
<groupId>com.sun.jmx</groupId>
<artifactId>jmxri</artifactId>
</exclusion>
</exclusions>
<scope>runtime</scope>
</dependency>


<dependency>
<groupId>javax.inject</groupId>
<artifactId>javax.inject</artifactId>
<version>1</version>
</dependency>


<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>


<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>

</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<additionalProjectnatures>
<projectnature>org.springframework.ide.eclipse.core.springnature</projectnature>
</additionalProjectnatures>
<additionalBuildcommands>
<buildcommand>org.springframework.ide.eclipse.core.springbuilder</buildcommand>
</additionalBuildcommands>
<downloadSources>true</downloadSources>
<downloadJavadocs>true</downloadJavadocs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<compilerArgument>-Xlint:all</compilerArgument>
<showWarnings>true</showWarnings>
<showDeprecation>true</showDeprecation>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<configuration>
<mainClass>org.test.int1.Main</mainClass>
</configuration>
</plugin>
</plugins>
</build>

</project>

websocket相关类：

我们需要编写三个WebSocket的处理类，这里是利用了Spring WebSocket模块，三个类分别是WebSocket处理类SocketHandler、WebSocket配置类WebSocketConfig以及WebSocket拦截器WebSocketInterceptor。

在开始编写之前记得在Spring配置文件中添加Spring注解支持：

<context:component-scan base-package="com.accenture.demo" />

WebSocketConfig.java

package com.accenture.socket;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

/**
* @desp websocket配置
*
*/
@Configuration
@EnableWebMvc
@EnableWebSocket
public class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer{

@Autowired
private SocketHandler socketHandler;

@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
//注册处理拦截器,拦截url为socketServer的请求
registry.addHandler(socketHandler, "/socketServer").addInterceptors(new WebSocketInterceptor());

//注册SockJs的处理拦截器,拦截url为/sockjs/socketServer的请求
registry.addHandler(socketHandler, "/sockjs/socketServer").addInterceptors(new WebSocketInterceptor()).withSockJS();
}

}

如上所示，在WebSocketConfig.java中，我们为SocketHandler注册了两个url请求，并应用了我们所定义的WebSocketInterceptor()拦截器。

WebSocketInterceptor.java

package com.accenture.socket;

import java.util.Map;

import javax.servlet.http.HttpSession;

import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.HandshakeInterceptor;

/**
* @desp websocket拦截器
*
*/
public class WebSocketInterceptor implements HandshakeInterceptor{

@Override
public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response,
WebSocketHandler handler, Exception exception) {

}

/**
* @desp 将HttpSession中对象放入WebSocketSession中
*/
@Override
public boolean beforeHandshake(ServerHttpRequest request,
ServerHttpResponse response, WebSocketHandler handler,
Map<String, Object> map) throws Exception {
if(request instanceof ServerHttpRequest){
ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
HttpSession session = servletRequest.getServletRequest().getSession();
if(session!=null){
//区分socket连接以定向发送消息
map.put("user", session.getAttribute("user"));
}
}
return true;
}

}

如上所示，在执行客户端服务器端握手之前，也就是在beforeHandshake()方法中，我们将HttpSession中我们登录后存储的对象放到WebSocketSession中，以此实现定向发送消息。

SocketHandler.java

package com.accenture.socket;

import java.io.IOException;
import java.util.ArrayList;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketMessage;
import org.springframework.web.socket.WebSocketSession;

/**
* @desp Socket处理类
* @author liulichao@ruc.edu.cn
*
*/
@Service
public class SocketHandler implements WebSocketHandler{

private static final Logger logger;
private static final ArrayList<WebSocketSession> users;

static{
users = new ArrayList<WebSocketSession>();
logger = LoggerFactory.getLogger(SocketHandler.class);
}

@Override
public void afterConnectionEstablished(WebSocketSession session)
throws Exception {
logger.info("成功建立socket连接");
users.add(session);
String username = session.getAttributes().get("user").toString();
if(username!=null){
session.sendMessage(new TextMessage("我们已经成功建立socket通信了"));
}

}

@Override
public void handleMessage(WebSocketSession arg0, WebSocketMessage<?> arg1)
throws Exception {
// TODO Auto-generated method stub

}

@Override
public void handleTransportError(WebSocketSession session, Throwable error)
throws Exception {
if(session.isOpen()){
session.close();
}
logger.error("连接出现错误:"+error.toString());
users.remove(session);
}

@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus arg1)
throws Exception {
logger.debug("连接已关闭");
users.remove(session);
}

@Override
public boolean supportsPartialMessages() {
return false;
}

/**
* 给所有在线用户发送消息
*
* @param message
*/
public void sendMessageToUsers(TextMessage message) {
for (WebSocketSession user : users) {
try {
if (user.isOpen()) {
user.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}

/**
* 给某个用户发送消息
*
* @param userName
* @param message
*/
public void sendMessageToUser(String userName, TextMessage message) {
for (WebSocketSession user : users) {
if (user.getAttributes().get("user").equals(userName)) {
try {
if (user.isOpen()) {
user.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
break;
}
}
}

}

3.3 SpringMVC Controller类：

SocketController.java

package com.accenture.controller;

import javax.servlet.http.HttpSession;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.socket.TextMessage;

import com.accenture.socket.SocketHandler;

/**
* @desp Socket控制器
* @author liulichao@ruc.edu.cn
* @date 2016-5-6
*
*/
@Controller
public class SocketController{

private static final Logger logger = LoggerFactory.getLogger(SocketController.class);

@Autowired
private SocketHandler socketHandler;

@RequestMapping(value="/login")
public String login(HttpSession session){
logger.info("用户登录了建立连接啦");

session.setAttribute("user", "liulichao");

return "home";
}

@RequestMapping(value = "/message", method = RequestMethod.GET)
public String sendMessage(){

socketHandler.sendMessageToUser("liulichao", new TextMessage("这是一条测试的消息"));

return "message";
}

}

如上，在SocketController中我们定义了两个请求处理方法，首先执行login()后再session中存入user对象模拟用户已登录，而sendMessage()方法则是调用了sendMessageToUser()实现向某一个用户推送消息。

整个包结构如下

同时，在web.xml中需要所有servlet与filter中需要加入异步支持：

<async-supported>true</async-supported>

前端页面实现

模拟登录页面home.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String wsPath = "ws://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
<head>
<title>Home</title>
</head>
<body>
<h1>
Hello world! This is a WebSocket demo!
<div id="message">

</div>
</h1>

<script type="text/javascript" src="js/jquery-1.12.2.min.js"></script>
<script type="text/javascript" src="js/sockjs.min.js"></script>

<script type="text/javascript">

$(function(){
//建立socket连接
var sock;
if ('WebSocket' in window) {
sock = new WebSocket("<%=wsPath%>socketServer");
} else if ('MozWebSocket' in window) {
sock = new MozWebSocket("<%=wsPath%>socketServer");
} else {
sock = new SockJS("<%=basePath%>sockjs/socketServer");
}
sock.onopen = function (e) {
console.log(e);
};
sock.onmessage = function (e) {
console.log(e)
$("#message").append("<p><font color='red'>"+e.data+"</font>")
};
sock.onerror = function (e) {
console.log(e);
};
sock.onclose = function (e) {
console.log(e);
}
});

</script>

</body>

</html>

如上所示，我们访问login模拟登录后之后将跳到home.jsp，在页面中通过sockjs与服务器端我们注册的WebSocket访问接口实现握手建立socket连接。

推送消息页面message.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>message</title>
</head>
<body>
<h1>已经发送消息了</h1>

</body>

</html>

在访问/message过后将调用消息发送的函数实现后端消息向前端的推送。

首先，我们访问login函数，将跳至home.jsp视图，出现如下的页面：