单点登录（英语：Single sign-on，缩写为 SSO），又译为单一签入，一种对于许多相互关连，但是又是各自独立的软件系统，提供访问控制的属性。当拥有这项属性时，当用户登录时，就可以获取所有系统的访问权限，不用对每个单一系统都逐一登录。这项功能通常是以轻型目录访问协议（LDAP）来实现，在服务器上会将用户信息存储到LDAP数据库中。相同的，单一注销（single sign-off）就是指，只需要单一的注销动作，就可以结束对于多个系统的访问权限。

Security OAuth2 单点登录流程示意图

https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/security/SpringSecurity-OAuth2-sso.png

1. 访问client1
2. client1将请求导向sso-server
3. 同意授权
4. 携带授权码code返回client1
5. client1拿着授权码请求令牌
6. 返回JWT令牌
7. client1解析令牌并登录
8. client1访问client2
9. client2将请求导向sso-server
10. 同意授权
11. 携带授权码code返回client2
12. client2拿着授权码请求令牌
13. 返回JWT令牌
14. client2解析令牌并登录

用户的登录状态是由sso-server认证中心来保存的，登录界面和账号密码的验证也是sso-server认证中心来做的（client1和clien2返回token是不同的，但解析出来的用户信息是同一个用户）。

Security OAuth2 实现单点登录

项目结构

https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/security/spring-security-oauth2-sso01.png

sso-server

认证服务器

@Configuration
@EnableAuthorizationServer
public class SsoAuthorizationServerConfig extends AuthorizationServerConfigurerAdapter {

    /**
     * 客户端一些配置
     * @param clients
     * @throws Exception
     */
    @Override
    public void configure(ClientDetailsServiceConfigurer clients) throws Exception {
        clients.inMemory()
                .withClient("merryyou1")
                .secret("merryyousecrect1")
                .authorizedGrantTypes("authorization_code", "refresh_token")
                .scopes("all")
                .and()
                .withClient("merryyou2")
                .secret("merryyousecrect2")
                .authorizedGrantTypes("authorization_code", "refresh_token")
                .scopes("all");
    }

    /**
     * 配置jwttokenStore
     * @param endpoints
     * @throws Exception
     */
    @Override
    public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {
        endpoints.tokenStore(jwtTokenStore()).accessTokenConverter(jwtAccessTokenConverter());
    }

    /**
     * springSecurity 授权表达式，访问merryyou tokenkey时需要经过认证
     * @param security
     * @throws Exception
     */
    @Override
    public void configure(AuthorizationServerSecurityConfigurer security) throws Exception {
        security.tokenKeyAccess("isAuthenticated()");
    }

    /**
     * JWTtokenStore
     * @return
     */
    @Bean
    public TokenStore jwtTokenStore() {
        return new JwtTokenStore(jwtAccessTokenConverter());
    }

    /**
     * 生成JTW token
     * @return
     */
    @Bean
    public JwtAccessTokenConverter jwtAccessTokenConverter(){
        JwtAccessTokenConverter converter = new JwtAccessTokenConverter();
        converter.setSigningKey("merryyou");
        return converter;
    }
}

security配置

@Configuration
public class SsoSecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private UserDetailsService userDetailsService;

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.formLogin().loginPage("/authentication/require")
                .loginProcessingUrl("/authentication/form")
                .and().authorizeRequests()
                .antMatchers("/authentication/require",
                        "/authentication/form",
                        "/**/*.js",
                        "/**/*.css",
                        "/**/*.jpg",
                        "/**/*.png",
                        "/**/*.woff2"
                )
                .permitAll()
                .anyRequest().authenticated()
                .and()
                .csrf().disable();
//        http.formLogin().and().authorizeRequests().anyRequest().authenticated();
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService).passwordEncoder(passwordEncoder());
    }
}

SsoUserDetailsService

@Component
public class SsoUserDetailsService implements UserDetailsService {

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        return new User(username, passwordEncoder.encode("123456"), AuthorityUtils.commaSeparatedStringToAuthorityList("ROLE_USER"));
    }
}

application.yml

server:
  port: 8082
  context-path: /uaa
spring:
  freemarker:
    allow-request-override: false
    allow-session-override: false
    cache: true
    charset: UTF-8
    check-template-location: true
    content-type: text/html
    enabled: true
    expose-request-attributes: false
    expose-session-attributes: false
    expose-spring-macro-helpers: true
    prefer-file-system-access: true
    suffix: .ftl
    template-loader-path: classpath:/templates/

sso-client1

SsoClient1Application

@SpringBootApplication
@RestController
@EnableOAuth2Sso
public class SsoClient1Application {

    @GetMapping("/user")
    public Authentication user(Authentication user) {
        return user;
    }

    public static void main(String[] args) {
        SpringApplication.run(SsoClient1Application.class, args);
    }
}

application.yml

auth-server: http://localhost:8082/uaa # sso-server地址
server:
  context-path: /client1
  port: 8083
security:
  oauth2:
    client:
      client-id: merryyou1
      client-secret: merryyousecrect1
      user-authorization-uri: ${auth-server}/oauth/authorize #请求认证的地址
      access-token-uri: ${auth-server}/oauth/token #请求令牌的地址
    resource:
      jwt:
        key-uri: ${auth-server}/oauth/token_key #解析jwt令牌所需要密钥的地址

sso-client2

同sso-client1一致

效果如下：
[图片上传失败...(image-1c6041-1516894354927)]

代码下载

从我的 github 中下载，https://github.com/longfeizheng/sso-merryyou