一直没有用过websocket，今天出个需求，需要加个聊天模块，找到这篇博客 https://www.jianshu.com/p/47bc85b21912，照着代码运行了一下，了解一下
首先加入依赖

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-undertow</artifactId>
    </dependency>
    <!-- 静态资源 -->
    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>webjars-locator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>sockjs-client</artifactId>
        <version>1.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>stomp-websocket</artifactId>
        <version>2.3.3</version>
    </dependency>
    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>bootstrap</artifactId>
        <version>3.3.7</version>
    </dependency>
    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>jquery</artifactId>
        <version>3.1.0</version>
    </dependency>

由于这个项目加入了security
首先来配置一下security

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private AnyUserDetailsService anyUserDetailsService;

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(this.anyUserDetailsService);
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests().antMatchers("/", "/webjars/**", "/register", "/api/common/**", "/image/**", "/user/**").permitAll()
                .anyRequest().authenticated().and().formLogin().loginPage("/login").defaultSuccessUrl("/chat", true)
                .permitAll().and().logout().permitAll().and().csrf().disable();
    }

}

然后配置security的用户

import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.userdetails.User;

import java.util.Collection;

public class UserPrincipal extends User {

    private static final long serialVersionUID = -4735218819792872573L;

    private String nickname;

    private String avatar;

    public UserPrincipal(String username, String password, Collection<? extends GrantedAuthority> authorities) {
        super(username, password, authorities);
    }

    public UserPrincipal(String username, String password, boolean enabled, boolean accountNonExpired,
            boolean credentialsNonExpired, boolean accountNonLocked,
            Collection<? extends GrantedAuthority> authorities) {
        super(username, password, enabled, accountNonExpired, credentialsNonExpired, accountNonLocked, authorities);
    }

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

    public String getAvatar() {
        return avatar;
    }

    public void setAvatar(String avatar) {
        this.avatar = avatar;
    }
}

用户信息

import com.lijia.websocket.mongo.model.User;
import com.lijia.websocket.mongo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class AnyUserDetailsService implements UserDetailsService {
    private final static String ROLE_TAG = "ROLE_USER";

    @Autowired
    private UserService userService;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userService.getByUsername(username);
        if (user == null) {
            throw new UsernameNotFoundException("用户不存在");
        }
        List<GrantedAuthority> authorities = new ArrayList<>();
        authorities.add(new SimpleGrantedAuthority(ROLE_TAG));
        // 用户认证（用户名，密码，权限）
        UserPrincipal userPrincipal = new UserPrincipal(username, user.getPassword(), authorities);
        userPrincipal.setNickname(user.getNickname());
        userPrincipal.setAvatar(user.getAvatar());
        return userPrincipal;
    }

}

然后 配置websocket

@Configuration
@EnableWebSocketMessageBroker
@Log4j
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {

    @Override
    public void registerStompEndpoints(StompEndpointRegistry stompEndpointRegistry) {
        stompEndpointRegistry.addEndpoint("/any-socket").withSockJS();
    }

    @Override
    public void configureMessageBroker(MessageBrokerRegistry messageBrokerRegistry) {
        messageBrokerRegistry.setApplicationDestinationPrefixes("/app");
        messageBrokerRegistry.enableSimpleBroker("/topic", "/queue");
    }

    @Override
    public void configureWebSocketTransport(final WebSocketTransportRegistration registration) {
        registration.addDecoratorFactory(new WebSocketHandlerDecoratorFactory() {
            @Override
            public WebSocketHandler decorate(final WebSocketHandler handler) {
                return new WebSocketHandlerDecorator(handler) {
                    @Override
                    public void afterConnectionEstablished(final WebSocketSession session) throws Exception {
                        String username = session.getPrincipal().getName();
                        log.info("online: " + username);
                        super.afterConnectionEstablished(session);
                    }

                    @Override
                    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus)
                            throws Exception {
                        String username = session.getPrincipal().getName();
                        log.info("offline: " + username);
                        super.afterConnectionClosed(session, closeStatus);
                    }
                };
            }
        });
        super.configureWebSocketTransport(registration);
    }
}

主要聊天代码是

一个是群聊消息，一个是单聊消息。
这个项目直接使用map存储数据的，没用到数据库。
再看看聊天页面

2和3互相发消息，1收不到

大体就是通过websocket发布一些固定的topic，然后页面需要订阅这个topic，有消息就推送。
代码用作者博客里面的 https://github.com/ChinaSilence/any-chat就行。
我还是放到了自己练习项目 https://github.com/lijiaccy/springboot-sharding-table，在websocket文件夹下