websocket准实时推送消息

来源：互联网发布：什么软件可以写日记编辑：程序博客网时间：2024/05/21 06:50

在web项目中前端向后端请求数据时，如果要求数据的实时性，第一种方式是基于ajax的长轮训，第二种方式是websocket通讯，今天要介绍的是第二种方式。直接上代码。

进行websocket通讯的类，要加上component注解

@ServerEndpoint("/websocket/{uid}")@Component("websocket")public class SocketServer    {    private Session session;    private static ConcurrentHashMap< String , SocketServer>  map = new ConcurrentHashMap<String , SocketServer>();    //建立连接后，将session存在map中    @OnOpen    public void onOpen(@PathParam("uid") String uid, Session session ) {        this.session = session;        map.put(uid,this);    }   //遍历发送消息   public  void  sendMessage (String  message) {        for(SocketServer server :  map.values()){            try {                server.session.getBasicRemote().sendText(message);            } catch (IOException e) {                e.printStackTrace();            }        }   }}

定时器每隔55秒去查数据库中的order表，如果有新的记录增加，就往队列中加入一条消息

@Component@EnableSchedulingpublic class   Producer  {    Jedis jedis = new Jedis("127.0.0.1", 6379);    int tempId ;    @Scheduled(cron = "0/55 * * * * ?")    public  void  run(){        Class.forName("com.mysql.jdbc.Driver");        Connection con = DriverManager.getConnection("jdbc:mysql:///maetin","root","123456");        String sql = "select * from  tbl_product order by  id  desc limit 1";        try {            con = this.getConnection();            Statement stmt = con.createStatement();            ResultSet rs = stmt.executeQuery(sql);            while(rs.next()){                if(tempId == 0 ){                    tempId = rs.getInt("id");                }                if(tempId < rs.getInt("id")){                     tempId = rs.getInt("id");                    jedis.lpush("IdQueue" , tempId+"");                }            }        }catch (Exception e){            e.printStackTrace();        }finally {        }    }}

推送消息到前端

@Component@EnableSchedulingpublic class Consumer {    Jedis jedis = new Jedis("127.0.0.1", 6379);    @Autowired    private SocketServer socket;    @Autowired    private BusiService service;    @Scheduled(cron = "0/30* * * * ?")    public  void  run(){        String id = jedis.rpoplpush("IdQueue", "TempQueue");        if(null != id){            jedis.rpop("TempQueue");            socket.sendMessage("推送的消息");        }    }}

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