一．使用H5的websocket协议
参考：https://www.cnblogs.com/bianzy/p/5822426.html
接收onOpen接收参数：https://blog.csdn.net/u014175572/article/details/46693121
实现步骤
- 修改pom.xml
<!--加载websocket-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
<version>1.3.5.RELEASE</version>
</dependency>
- 建立websocket服务端 PayWebSocket
package domain.websocket;
import domain.domain.DomainResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;
/**
* 收银系统websocket服务端
* @author liangxifeng 2018-07-04
*/
@ServerEndpoint(value = "/websocket/pay/{mac}/{contractNum}",encoders = { ServerEncoder.class })
@Component
@Slf4j
public class PayWebSocket {
//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 payOnlineCount = 0;
//concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。
//private static CopyOnWriteArraySet<PayWebSocket> payWebSocketSet = new CopyOnWriteArraySet<PayWebSocket>();
//线程安全的map,key=mac地址，value=PayWebSocket对象
public static ConcurrentHashMap<String,PayWebSocket> payWebSocketMap = new ConcurrentHashMap<String, PayWebSocket>();
//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;
private String flag = "收银系统websocket=>";
/**
* 连接建立成功调用的方法
* @param mac mac地址
* @param contractNum 合同号
* @param session websocket会话
*/
@OnOpen
public void onOpen(@PathParam("mac") String mac,
@PathParam("contractNum") String contractNum, Session session) throws Exception{
logInfo("合同号 contractNum="+contractNum);
//验证参数
if(mac == null || mac.trim().isEmpty() || contractNum == null || contractNum.trim().isEmpty()){
sendMessage(new DomainResponse(0,"mac地址或收款合同号不可为空",0));
}
this.session = session;
//将PayWebSocket对象加入map中
payWebSocketMap.put(mac.trim(),this);
addOnlineCount(); //在线数加1
log.info("有新连接加入！当前在线人数为" + getOnlineCount());
}
/**
* 连接关闭调用的方法
*/
@OnClose
public void onClose() {
//payWebSocketSet.remove(this); //从set中删除
subOnlineCount(); //在线数减1
System.out.println("有一连接关闭！当前在线人数为" + getOnlineCount());
}
/**
* 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*/
@OnMessage
public void onMessage(String message, Session session) throws Exception{
System.out.println("来自客户端的消息:" + message);
// //群发消息
// for (PayWebSocket item : payWebSocketSet) {
// try {
// item.sendMessage(message);
// } catch (IOException e) {
// e.printStackTrace();
// }
// }
}
/**
* 打印日志信息
* @param msg
*/
public void logInfo(String msg){
log.info(this.flag+msg);
}
/**
* 发生错误时调用
*/
@OnError
public void onError(Session session, Throwable error) {
log.info("发生错误");
error.printStackTrace();
}
public void sendMessage(Object message) throws Exception {
this.session.getBasicRemote().sendObject(message);
//this.session.getAsyncRemote().sendText(message);
}
/**
* 群发自定义消息
*/
public static void sendInfo(Object message) throws Exception {
// for (PayWebSocket item : payWebSocketSet) {
// try {
// item.sendMessage(message);
// } catch (IOException e) {
// continue;
// }
// }
}
public static synchronized int getOnlineCount() {
return payOnlineCount;
}
/**
* 连接数+1
*/
public static synchronized void addOnlineCount() {
PayWebSocket.payOnlineCount++;
}
/**
* 连接数-1
*/
public static synchronized void subOnlineCount() {
if(payOnlineCount!=0){
PayWebSocket.payOnlineCount--;
}
}
}
- 创建配置文件，启动websocket服务 WebSocketConfig
package domain.util;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
/**
* 注入ServerEndpointExporter，这个bean会自动注册使用了@ServerEndpoint注解声明的Websocket endpoint
* @author liangxifeng 2018-07-04
*/
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
- 为了在websocket服务器使用sendObject给客户端发送object,需要实现如下ServerEncoder类
package domain.websocket;
import domain.domain.DomainResponse;
import net.sf.json.JSONObject;
import javax.websocket.EncodeException;
import javax.websocket.Encoder;
import javax.websocket.EndpointConfig;
/**
* ServerEncoder为了防止在websocket向客户端发送sendObject方法的时候提示如下错误：
* javax.websocket.EncodeException: No encoder specified for object of class [class org.ywzn.po.Messagepojo]
*/
public class ServerEncoder implements Encoder.Text<DomainResponse> {
//代表websocket调用sendObject方法返回客户端的时候，必须返回的是DomainResponse对象
@Override
public String encode(DomainResponse domainResponse) {
//将java对象转换为json字符串
return JSONObject.fromObject(domainResponse).toString();
}
@Override
public void init(EndpointConfig endpointConfig) { }
@Override
public void destroy() { }
}
-
目录结构
websocket.jpg
-
html内容 websocket-java.html
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1, maximum-scale=1, user-scalable=no">
<title>websocket-java</title>
<script src="/static/js/WebSocket.js"></script></script>
</head>
<body>
Welcome<br/>
<input id="text" type="text" /><button onclick="send()">Send</button> <button onclick="closeWebSocket()">Close</button>
<div id="message">
</div>
</body>
<script type="text/javascript">
WEB_SOCKET_SWF_LOCATION="/static/js/WebSocket.swf";
WEB_SOCKET_DEBUG=true;
var websocket = null;
//判断当前浏览器是否支持WebSocket
if('WebSocket' in window){
websocket = new WebSocket("ws://localhost:8082/websocket");
}
else{
alert('Not support websocket')
}
var websocketPay = null;
if('WebSocket' in window){
websocketPay = new WebSocket("ws://localhost:8082/websocket/pay/2/151200234");
}
//连接成功建立的回调方法
websocketPay.onopen = function(event){
setMessageInnerHTML("pay-open");
}
//接收到消息的回调方法
websocketPay.onmessage = function(event){
console.log('pay =='+event.data)
var data = eval("(" + event.data + ")"); //解析对象
setMessageInnerHTML('pay message ==='+event.data);
}
//连接发生错误的回调方法
websocket.onerror = function(){
setMessageInnerHTML("error");
};
//连接成功建立的回调方法
websocket.onopen = function(event){
setMessageInnerHTML("open");
}
//接收到消息的回调方法
websocket.onmessage = function(event){
console.log(event.data)
var data = eval("(" + event.data + ")"); //解析对象
//console.log(typeof(JSON.parse(event.data)));
//var data = JSON.parse(event.data);
setMessageInnerHTML(typeof(data));
}
//连接关闭的回调方法
websocket.onclose = function(){
setMessageInnerHTML("close");
}
//监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function(){
websocket.close();
}
//将消息显示在网页上
function setMessageInnerHTML(innerHTML){
document.getElementById('message').innerHTML += innerHTML + '<br/>';
}
//关闭连接
function closeWebSocket(){
websocket.close();
}
//发送消息
function send(){
var message = document.getElementById('text').value;
websocket.send(message);
}
</script>
</html>
-
访问效果
image.png
服务器可以给指定的用户发消息
package domain.controller;
import domain.domain.DomainResponse;
import domain.domain.Exhibition;
import domain.websocket.PayWebSocket;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
@RestController
@RequestMapping(value = "/exhibiton")
public class ExhibitonController {
@Autowired
private InsertExhibitionService insertExhibitionService;
@GetMapping(value = "/sendMsg/{mac}")
/**
* 指定某个websocket发送从服务器发送到浏览器，服务器主动推送
*/
private DomainResponse testSendMsg(@PathVariable("mac") String mac ) throws Exception{
DomainResponse msg = new DomainResponse(Integer.parseInt(mac),mac,"指定给"+mac+"用户发消息");
PayWebSocket payWebSocket = PayWebSocket.payWebSocketMap.get(mac);
if(payWebSocket == null)
{
return new DomainResponse(0,"没有该用户",0);
}
payWebSocket.sendMessage(msg);
return msg;
}
}
访问地址：http://192.168.9.209:8082/exhibiton/sendMsg/2
注意：以上方式IE8不兼容，所以放弃使用；
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