WebSocket设置在线离线以及优先展示最近聊天的人
1.设置在线状态
主要逻辑:
1.用户连接之后,首先后端执行onOpen,传入用户的id,然后写入到redis中
RedisConfig.java 中加入
@Bean
public RedisTemplate<String, String> redisTemplate() {
RedisTemplate<String, String> redisTemplate = new StringRedisTemplate();
return redisTemplate;
}
@Bean
public ValueOperations<String, String> stringValueOperations(RedisTemplate<String, String> redisTemplate) {
return redisTemplate.opsForValue();
}
@OnOpen
public void onOpen(Session session,@PathParam("id") String id) {
sessionMap.put(session.getId(), session);
userMap.put(session.getId(),id);
long timestamp = System.currentTimeMillis();
stringRedisTemplate.opsForValue().set(id,"存在"+timestamp);
log.info("[onOpen] 新建连接,session={}, 当前在线人数为:{}", session.getId(), userMap.size());
this.sendAllMessage(JSONUtil.toJsonStr(Dict.create().set("users", userMap.values())));
}
@OnClose
public void onClose(Session session) {
stringRedisTemplate.delete(userMap.get(session.getId()));
userMap.remove(session.getId());
sessionMap.remove(session.getId());
log.info("[onClose] 有一连接关闭,session={}, 当前在线人数为:{}", session.getId(), userMap.size());
}
2.前端监听变化
client.onmessage = (msg) => {
if (msg.data) {
let json = JSON.parse(msg.data)
if (json.users && json.users.length){
this.loadOnline(json);
return
}
if (json.content && (json.fromuser === this.fromUser && json.touser === this.toUser)
|| json.touser === this.fromUser && json.fromuser === this.toUser) {
this.messages.push(json)
this.scrollToBottom()
}
if (this.toUser === json.fromuser) {
this.setUnReadNums()
} else {
this.loadUnReadNums()
}
}
}
3.查询在线人数
loadOnline(json){
request.get('/user/selectAllOnline').then(res => {
res.data = res.data.filter(v => (v.id + '_' + v.name) !== this.fromUser)
this.$set(this.users, 'USER', res.data)
})
},
4.后端进行业务逻辑判断
public List<User> selectAllOnline(User userNo) {
List<User> userList = userMapper.selectAll(userNo);
for(User user:userList){
String key = Integer.toString(user.getId());
String value = stringRedisTemplate.opsForValue().get(key);
if(value != null){
String username = user.getUsername()+"在线";
user.setUsername(username);
}
}
return userList;
}
5.注意在WebSocket直接写Redis相关操作会报错
解决方案看该帖子:https://blog.csdn.net/weixin_45730605/article/details/135898294?spm=1001.2014.3001.5502