下面分别介绍搭建方法:
一、直接使用Java EE的api进行搭建。
一共3个步骤:
1、添加依赖
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>7.0</version>
<scope>provided</scope>
</dependency>
2、使用注解@ServerEndpoint
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Logger;
/**
* WebSocket连接 sessionKey是url中的参数
*/
@ServerEndpoint("/websocket/{sessionKey}")
public class WebSocket {
private static final Logger log = Logger.getLogger(WebSocket.class.getName());
//静态变量,用来记录当前在线连接数。应该把它设计成线程安全的。
private static int onlineCount = 0;
//concurrent包的线程安全,用来存放每个客户端对应的MyWebSocket对象。若要实现服务端与单一客户端通信的话,可以使用Map来存放,其中Key可以为用户标识
private static Map<String, WebSocket> webSockets = new ConcurrentHashMap<>();
//与某个客户端的连接会话,需要通过它来给客户端发送数据
private Session session;
/**
* 连接建立成功调用的方法
*
* @param session 可选的参数。session为与某个客户端的连接会话,需要通过它来给客户端发送数据
* @param sessionKey url地址参数
*/
@OnOpen
public void onOpen(Session session, @PathParam("sessionKey") String sessionKey) {
if (!webSockets.containsKey(sessionKey)) {
this.session = session;
webSockets.put(sessionKey, this);
addOnlineCount();
log.info("当前websocket连接数:" + onlineCount);
}
}
/**
* 连接关闭调用的方法
*
* @param sessionKey url地址参数
*/
@OnClose
public void onClose(@PathParam("sessionKey") String sessionKey) {
if (webSockets.containsKey(sessionKey)) {
webSockets.remove(sessionKey);
subOnlineCount();
log.info("当前websocket连接数:" + onlineCount);
}
}
/**
* 收到客户端消息后调用的方法
*
* @param message 客户端发送过来的消息
* @param session 可选的参数
*/
@OnMessage
public void onMessage(String message, Session session) {
log.info("来自客户端的消息:" + message);
}
/**
* 发生错误时调用
*
* @param session 可选的参数
* @param error 错误消息
*/
@OnError
public void onError(Session session, Throwable error) {
log.info("websocket发生错误:" + error);
}
/**
* 该方法没有用注解,是根据自己需要添加的方法。在自己的业务中调用,发送消息给前端。
*
* @param sessionKey
* @param message 返回的结果
* @throws IOException
*/
public static void sendMessage(String sessionKey, String message) throws IOException {
WebSocket webSocket = webSockets.get(sessionKey);
if (null != webSocket) {
log.info("websocket发送消息:" + message);
//同步发送 发送第二条时,必须等第一条发送完成
webSocket.session.getBasicRemote().sendText(message);
//异步发送
//webSocket.session.getAsyncRemote().sendText(message);
}
}
public static synchronized int getOnlineCount() {
return onlineCount;
}
public static synchronized void addOnlineCount() {
onlineCount++;
}
public static synchronized void subOnlineCount() {
onlineCount--;
}
}
3、测试
在线WebSocket测试:http://coolaf.com/tool/chattest
输入地址进行测试即可,举例:ws://localhost:8080/websocket/sessionKey
补充:也可以使用java搭建客户端程序测试,测试的例程放到后面去了~~
二、和springboot整合的WebSocket服务(功能更加强大)
看下效果:<ignore_js_op>
<ignore_js_op>
http://localhost:8080/websocket/sendToUser?username=river&info=你找我干嘛?
maven依赖如下:
maven依赖如下:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
<version>2.0.4.RELEASE</version>
</dependency>
1、控制类
package com.boot.river.websocket;
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.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.socket.TextMessage;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
@Controller
@RequestMapping(value = "/websocket", method = {RequestMethod.POST, RequestMethod.GET})/*GET请求开放用于测试,最好只允许POST请求*/
public class WebSocketController {
@Autowired
SpringWebSocketHandler springWebSocketHandler;
/**
* 登录将username放入session中,然后在拦截器HandshakeInterceptor中取出
*/
@ResponseBody
@RequestMapping("/login")
public String login(HttpServletRequest request, @RequestParam(value = "username") String username, @RequestParam(value = "password") String password) {
System.out.println("登录:" + username + ":" + password);
HttpSession session = request.getSession();
if (null != session) {
session.setAttribute("SESSION_USERNAME", username);
return "success";
} else {
return "fail";
}
}
/**
* 指定发送
*/
@ResponseBody
@RequestMapping("/sendToUser")
public String send(@RequestParam(value = "username") String username, @RequestParam(value = "info") String info) {
springWebSocketHandler.sendMessageToUser(username, new TextMessage(info));
System.out.println("发送至:" + username);
return "success";
}
/**
* 广播
*/
@ResponseBody
@RequestMapping("/broadcast")
public String broadcast(@RequestParam(value = "info") String info) {
springWebSocketHandler.sendMessageToUsers(new TextMessage("广播消息:" + info));
System.out.println("广播成功");
return "success";
}
}
2、配置类(实现WebSocketConfigurer接口 )
@Configuration
@EnableWebSocket
public class SpringWebSocketConfig implements WebSocketConfigurer {
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(getSpringWebSocketHandler(), "/websocket/server")
.addInterceptors(getInterceptor()).setAllowedOrigins("*");
registry.addHandler(getSpringWebSocketHandler(), "/sockjs/server").setAllowedOrigins("*")
.addInterceptors(getInterceptor()).withSockJS();
}
@Bean
public SpringWebSocketHandler getSpringWebSocketHandler() {
return new SpringWebSocketHandler();
}
@Bean
public SpringWebSocketHandlerInterceptor getInterceptor() {
return new SpringWebSocketHandlerInterceptor();
}
}
3、处理类(实现了WebSocketHandler接口)
package com.boot.river.websocket;
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;
import java.util.HashMap;
import java.util.Map;
public class SpringWebSocketHandler extends TextWebSocketHandler {
/**
* 存储用户id和其对应的session
*/
private static final Map<String, WebSocketSession> users = new HashMap<>();
/**
* 用户名key值
*/
private static final String USER_ID = "WEBSOCKET_USERID";
/**
* 连接建立后触发
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) {
System.out.println("成功建立websocket连接!");
String userId = (String) session.getAttributes().get(USER_ID);//取出在拦截器中存储的username
users.put(userId, session);
System.out.println("当前线上用户数量:" + users.size());
}
/**
* 关闭连接时触发
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) {
String userId = (String) session.getAttributes().get(USER_ID);
System.out.println("用户" + userId + "已退出!");
users.remove(userId);
System.out.println("剩余在线用户" + users.size());
}
/**
* 接收消息
*/
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
super.handleTextMessage(session, message);
System.out.println("收到消息:" + message);
if (message.getPayload().contains("在吗")) {
session.sendMessage(new TextMessage("对方不在线!"));
}
}
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
if (session.isOpen()) {
session.close();
}
System.out.println("传输出现异常,关闭websocket连接... ");
String userId = (String) session.getAttributes().get(USER_ID);
users.remove(userId);
}
public boolean supportsPartialMessages() {
return false;
}
/**
* 给某个用户发送消息
*/
public void sendMessageToUser(String userId, TextMessage message) {
for (String id : users.keySet()) {
if (id.equals(userId)) {
try {
if (users.get(id).isOpen()) {
users.get(id).sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
break;
}
}
}
/**
* 给所有在线用户发送消息
*/
public void sendMessageToUsers(TextMessage message) {
for (String userId : users.keySet()) {
try {
if (users.get(userId).isOpen()) {
users.get(userId).sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
4、拦截器(实现HandshakeInterceptor接口)
package com.boot.river.websocket;
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.support.HttpSessionHandshakeInterceptor;
import javax.servlet.http.HttpSession;
import java.util.Map;
public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
Map<String, Object> attributes) throws Exception {
System.out.println("Before Handshake");
if (request instanceof ServletServerHttpRequest) {
ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
HttpSession session = servletRequest.getServletRequest().getSession(false);//获取session时,如果没有则返回null
if (session != null) {
String userName = (String) session.getAttribute("SESSION_USERNAME");//在登录时保存的用户名
if (userName != null) {
attributes.put("WEBSOCKET_USERID", userName);//放入attributes中,可以在处理器的WebSocketSession中取出
}
}
}
return super.beforeHandshake(request, response, wsHandler, attributes);
}
@Override
public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
Exception ex) {
super.afterHandshake(request, response, wsHandler, ex);
System.out.println("after Handshake");
}
}
参考:
https://my.oschina.net/u/3445245/blog/3003208
https://blog.****.net/runbat/article/details/80985944
https://docs.spring.io/spring/docs/5.0.0.BUILD-SNAPSHOT/spring-framework-reference/html/websocket.html
下面分别介绍websocket的java客户端请求和js客户端请求
1、java客户端
添加依赖:
<dependency>
<groupId>org.java-websocket</groupId>
<artifactId>Java-WebSocket</artifactId>
<version>1.4.0</version>
</dependency>
package com.river.websocket;
import org.java_websocket.enums.ReadyState;
import java.net.URISyntaxException;
/**
* @author river
* @date 2019-12-6
*/
public class Client {
public static void main(String[] args) throws URISyntaxException, InterruptedException {
MyWebSocketClient client = new MyWebSocketClient("ws://localhost:8080/websocket/server");
client.connect();
while (client.getReadyState() != ReadyState.OPEN) {
System.out.println("连接状态:" + client.getReadyState());
Thread.sleep(100);
}
client.send("测试数据!");
client.close();
}
}
继承WebsocketClient
package com.river.websocket;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;
import java.net.URI;
import java.net.URISyntaxException;
public class MyWebSocketClient extends WebSocketClient {
MyWebSocketClient(String url) throws URISyntaxException {
super(new URI(url));
}
@Override
public void onOpen(ServerHandshake shake) {
System.out.println(shake.getHttpStatusMessage());
}
@Override
public void onMessage(String paramString) {
System.out.println(paramString);
}
@Override
public void onClose(int paramInt, String paramString, boolean paramBoolean) {
System.out.println("关闭");
}
@Override
public void onError(Exception e) {
System.out.println("发生错误");
}
}
2、js客户端
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<title>websocket</title>
<script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
<script type="text/javascript" src="http://cdn.bootcss.com/sockjs-client/1.1.1/sockjs.js"></script>
<script type="text/javascript">
var websocket = null;
if (\'WebSocket\' in window) {
websocket = new WebSocket("ws://localhost:8080/websocket/server");
} else if (\'MozWebSocket\' in window) {
websocket = new MozWebSocket("ws://localhost:8080/websocket/server");
} else {
websocket = new SockJS("http://localhost:8080/sockjs/server");
}
websocket.onopen = onOpen;
websocket.onmessage = onMessage;
websocket.onerror = onError;
websocket.onclose = onClose;
function onOpen(event) {
alert(event.type);
}
function onMessage(messageEvent) {
alert(messageEvent.data);
}
function onError(event) {
}
function onClose(closeEvent) {
alert(closeEvent.reason);
}
function doSendUser() {
if (websocket.readyState === websocket.OPEN) {
var msg = document.getElementById("inputMsg").value;
websocket.send(msg);//发送消息
alert("发送成功!");
} else {
alert("连接失败!");
}
}
window.close = function () {
websocket.onclose();
};
function websocketClose() {
websocket.close();
alert("连接关闭");
}
</script>
</head>
<body>
请输入:<input id="inputMsg" name="inputMsg"/>
<button οnclick="doSendUser();">发送</button>
<button οnclick="websocketClose();">关闭连接</button>
</body>
</html>
补充:登录方式除了在Controller中处理,还可以在Websocket中接收到的消息进行登录处理。
更多java学习资料可关注:itheimaGZ获取