websocket 自定义使用(3)
文章目录
- 1.添加依赖
- 2.编辑WebSocketConfig，
- 3.编写WebSocketHandlerInterceptor
- 4.编写MyWebSocketHandler
-
- 使用
- 5.自定义解码器
-
- 使用
1.添加依赖
org.springframework
spring-messaging
4.1.7.RELEASE
org.springframework
spring-websocket
4.1.7.RELEASE
javax.websocket
javax.websocket-api
1.0
provided
2.编辑WebSocketConfig，
根据spring文档，编写websocketConfig，这里可参看文档，xml配置和使用注解两种方式，我选择注解方式
registerWebSocketHandlers：这个方法是向spring容器注册一个handler地址，我把他理解成requestMapping（也可以理解为@ServerEndpoint(“/webSocket”)）
addInterceptors：拦截器，当建立websocket连接的时候，我们可以通过继承spring的HttpSessionHandshakeInterceptor来搞事情。
setAllowedOrigins：跨域设置，表示所有域名都可以，不限制， 域包括ip：port, 指定可以是任意的域名，不加的话默认localhost+本服务端口
withSockJS： 这个是应对浏览器不支持websocket协议的时候降级为轮询的处理。
@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(webSocketHandler(), "/websocket/socketServer")
.addInterceptors(new WebSocketHandlerInterceptor()).setAllowedOrigins("*");
registry.addHandler(webSocketHandler(), "/sockjs/socketServer").setAllowedOrigins("http://localhost:28180")
.addInterceptors(new WebSocketHandlerInterceptor()).withSockJS();
}
@Bean
public TextWebSocketHandler webSocketHandler() {
return new WebSocketHandler();
}
}
3.编写WebSocketHandlerInterceptor
这个是创建websocket连接是的拦截器，记录建立连接的用户的session以便根据不同session来通信
public class WebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
Map attributes) throws Exception {
System.out.println("Before Handshake");
if (request instanceof ServletServerHttpRequest) {
ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
HttpSession session = servletRequest.getServletRequest().getSession(false);
if (session != null) {
//使用userName区分WebSocketHandler，以便定向发送消息
String userName = (String) session.getAttribute("SESSION_USERNAME"); //一般直接保存user实体
if (userName != null) {
attributes.put("WEBSOCKET_USERID", userName);
}
}
}
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);
}
}
4.编写MyWebSocketHandler
@Configuration
public class MyWebSocketHandler extends TextWebSocketHandler {
//Map来存储WebSocketSession，key用USER_ID 即在线用户列表
private static ConcurrentHashMap users = new ConcurrentHashMap<>();
//用户标识
private static final String USER_ID = "WEBSOCKET_USERID"; //对应监听器从的key
public MYWebSocketHandler() {
}
/**
* 连接成功时候，会触发页面上onopen方法
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
System.out.println("成功建立websocket连接!");
String userId = session.getId();
users.put(userId, session);
System.out.println("当前线上用户数量:" + users.size());
//这块会实现自己业务，比如，当用户登录后，会把离线消息推送给用户
//TextMessage returnMessage = new TextMessage("成功建立socket连接，你将收到的离线");
//session.sendMessage(returnMessage);
}
/**
* 关闭连接时触发
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
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());
}
/**
* js调用websocket.send时候，会调用该方法
*/
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
/**
* 收到消息，自定义处理机制，实现业务
*/
System.out.println("服务器收到消息：" + message);
if (message.getPayload().startsWith("#anyone#")) { //单发某人
sendMessageToUser((String) session.getAttributes().get(USER_ID), new TextMessage("服务器单发：" + message.getPayload()));
} else if (message.getPayload().startsWith("#everyone#")) {
sendMessageToUsers(new TextMessage("服务器群发：" + message.getPayload()));
} else {
}
}
@Override
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);
}
@Override
public boolean supportsPartialMessages() {
return false;
}
/**
* 给某个用户发送消息
*
* @param userId
* @param message
*/
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
*
* @param message
*/
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();
}
}
}
}
使用
@Autowired
MyWebSocketHandler webSocket;
5.自定义解码器
public class WebSocketCustomEncoding implements Encoder.Text使用
@ServerEndpoint(value = "/webSocketService", encoders = {ImageEncoder.class})