一个多租户的Javaweb项目，项目使用技术为spring boot+thymeleaf+jpa，实现根据浏览器中输入网址的企业ID参数来进行多租户的单点登录，单点登录用到的技术：saml2.0,saml的各种配置信息存放在数据库中，IDP服务用到时是微软的ADFS。实现以上业务代码

首先，我们需要在Spring Boot中实现多租户的支持。这可以通过使用Spring的`MultiTenancy`功能来实现。具体来说，我们可以创建一个`TenantContext`类来跟踪当前租户的信息，例如企业ID。这个类可以使用`ThreadLocal`来存储当前租户的信息。我们还需要创建一个`TenantInterceptor`来拦截所有的请求，并从浏览器中的企业ID参数中解析出当前租户的信息，然后将其存储到`TenantContext`中。

接下来，我们需要实现单点登录。为此，我们可以使用SAML 2.0协议。SAML是一种基于XML的标准，用于在不同的安全域之间传输身份验证和授权数据。我们可以使用Spring Security SAML扩展来实现SAML支持。具体来说，我们需要配置一个SAML认证提供程序（IDP）和一个SAML服务提供程序（SP）。IDP是负责处理用户身份验证请求的服务器，而SP是负责向IDP发出身份验证请求的服务器。

在我们的应用程序中，我们可以将IDP配置信息存储在数据库中，并在运行时从数据库中读取这些配置信息。然后，我们可以使用Spring Security SAML扩展来配置SP。具体来说，我们需要配置SP的元数据和信任关系。元数据是SAML实体的描述信息，包括其公钥和证书等。信任关系用于指定SP和IDP之间的互信关系。

一旦我们完成了SAML配置，我们就可以在我们的应用程序中实现单点登录。具体来说，我们需要在我们的控制器中添加一个SAML认证请求处理程序，并在用户成功身份验证后将其重定向到我们的应用程序。在这个过程中，我们还需要将用户的SAML证书存储在我们的数据库中。这可以通过使用Spring Security的`AuthenticationSuccessHandler`接口来实现。

最后，我们还需要为我们的应用程序添加安全性。具体来说，我们可以使用Spring Security来限制对受保护资源的访问。我们可以创建一个安全配置类来配置Spring Security，并使用注释来指定哪些资源需要进行身份验证和授权。

以下是一个示例代码，展示了如何在Spring Boot应用程序中实现多租户支持和SAML单点登录：

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private CustomUserDetailsService userDetailsService;

    @Autowired
    private DataSource dataSource;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .antMatchers("/admin/**").hasRole("ADMIN")
                .antMatchers("/user/**").hasAnyRole("USER", "ADMIN")
                .anyRequest().authenticated()
                .and()
                .formLogin().permitAll()
                .and()
                .logout().permitAll();
    }

    @Override
    public void configure(WebSecurity web) throws Exception {
        web.ignoring().antMatchers("/resources/**");
    }

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

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

    @Bean
    public SAMLUserDetailsService samlUserDetailsService() {
        return new CustomSAMLUserDetailsService();
    }

    @Bean
    public SAMLConfigurer saml() {
        return new SAMLConfigurer();
    }

    @Bean
    public SAMLAuthenticationProvider samlAuthenticationProvider() {
        SAMLAuthenticationProvider samlAuthenticationProvider = new SAMLAuthenticationProvider();
        samlAuthenticationProvider.setUserDetails(samlUserDetailsService());
        samlAuthenticationProvider.setForcePrincipalAsString(false);
        return samlAuthenticationProvider;
    }

    @Bean
    public SAMLContextProviderImpl contextProvider() {
        return new SAMLContextProviderImpl();
    }

    @Bean
    public SAMLBootstrap samlBootstrap() {
        return new SAMLBootstrap();
    }

    @Bean
    public StaticBasicParserPool parserPool() {
        return new StaticBasicParserPool();
    }

    @Bean
    public ExtendedMetadataDelegate idpMetadataProvider() throws MetadataProviderException {
        HTTPMetadataProvider httpMetadataProvider = new HTTPMetadataProvider("idp-metadata-url", 5000);
        httpMetadataProvider.setParserPool(parserPool());
        ExtendedMetadataDelegate extendedMetadataDelegate = new ExtendedMetadataDelegate(httpMetadataProvider, extendedMetadata());
        extendedMetadataDelegate.setMetadataTrustCheck(true);
        extendedMetadataDelegate.setMetadataRequireSignature(false);
        return extendedMetadataDelegate;
    }

    @Bean
    public ExtendedMetadata extendedMetadata() {
        ExtendedMetadata extendedMetadata = new ExtendedMetadata();
        extendedMetadata.setIdpDiscoveryEnabled(false);
        extendedMetadata.setSignMetadata(false);
        extendedMetadata.setEcpEnabled(true);
        return extendedMetadata;
    }

    @Bean
    public MetadataGenerator metadataGenerator() {
        MetadataGenerator metadataGenerator = new MetadataGenerator();
        metadataGenerator.setEntityId("entity-id");
        metadataGenerator.setEntityBaseURL("entity-base-url");
        metadataGenerator.setExtendedMetadata(extendedMetadata());
        metadataGenerator.setIncludeDiscoveryExtension(false);
        metadataGenerator.setKeyManager(keyManager());
        return metadataGenerator;
    }

    @Bean
    public KeyManager keyManager() {
        DefaultResourceLoader loader = new DefaultResourceLoader();
        Resource storeFile = loader.getResource("classpath:saml/keystore.jks");
        String storePass = "store-pass";
        Map<String, String> passwords = new HashMap<>();
        passwords.put("key-alias", "key-pass");
        return new JKSKeyManager(storeFile, storePass, passwords, "key-alias");
    }

    @Bean
    public SAMLProcessingFilter samlWebSSOProcessingFilter() throws Exception {
        SAMLProcessingFilter samlWebSSOProcessingFilter = new SAMLProcessingFilter();
        samlWebSSOProcessingFilter.setAuthenticationManager(authenticationManager());
        samlWebSSOProcessingFilter.setAuthenticationSuccessHandler(samlAuthenticationSuccessHandler());
        samlWebSSOProcessingFilter.setAuthenticationFailureHandler(samlAuthenticationFailureHandler());
        return samlWebSSOProcessingFilter;
    }

    @Bean
    public SAMLAuthenticationSuccessHandler samlAuthenticationSuccessHandler() {
        return new CustomSAMLAuthenticationSuccessHandler();
    }

    @Bean
    public SAMLAuthenticationFailureHandler samlAuthenticationFailureHandler() {
        return new SimpleSAMLAuthenticationFailureHandler();
    }

    @Bean
    public SAMLLogoutFilter samlLogoutFilter() {
        return new SAMLLogoutFilter(samlLogoutSuccessHandler(),
                new LogoutHandler[]{logoutHandler()},
                new LogoutHandler[]{logoutHandler()});
    }

    @Bean
    public SAMLLogoutSuccessHandler samlLogoutSuccessHandler() {
        return new CustomSAMLLogoutSuccessHandler();
    }

    @Bean
    public SecurityContextLogoutHandler logoutHandler() {
        SecurityContextLogoutHandler logoutHandler = new SecurityContextLogoutHandler();
        logoutHandler.setClearAuthentication(true);
        logoutHandler.setInvalidateHttpSession(true);
        return logoutHandler;
    }

    @Bean
    public SAMLDiscovery samlIDPDiscovery() {
        return new SAMLDiscovery();
    }

    @Bean
    public SAMLDefaultEntryPoint samlEntryPoint() {
        SAMLDefaultEntryPoint samlDefaultEntryPoint = new SAMLDefaultEntryPoint();
        samlDefaultEntryPoint.setDefaultProfileOptions(defaultWebSSOProfileOptions());
        return samlDefaultEntryPoint;
    }

    @Bean(name = "samlWebSSOProfileOptions")
    public WebSSOProfileOptions defaultWebSSOProfileOptions() {
        WebSSOProfileOptions webSSOProfileOptions = new WebSSOProfileOptions();
        webSSOProfileOptions.setIncludeScoping(false);
        return webSSOProfileOptions;
    }

    @Bean
    public SAMLEntryPoint samlLogoutEntryPoint() {
        SAMLLogoutProcessingFilter samlLogoutProcessingFilter = new SAMLLogoutProcessingFilter(samlLogoutSuccessHandler(), logoutHandler());
        samlLogoutProcessingFilter.setFilterProcessesUrl("/logout");
        return samlLogoutProcessingFilter;
    }

    @Bean
    public SAMLProcessorImpl processor() {
        Collection<SAMLBinding> bindings = new ArrayList<>();
        bindings.add(httpRedirectDeflateBinding());
        bindings.add(httpPostBinding());
        bindings.add(artifactBinding(parserPool(), velocityEngine()));
        bindings.add(paosBinding());
        return new SAMLProcessorImpl(bindings);
    }

    @Bean
    public HTTPRedirectDeflateBinding httpRedirectDeflateBinding() {
        return new HTTPRedirectDeflateBinding(parserPool());
    }

    @Bean
    public HTTPPostBinding httpPostBinding() {
        return new HTTPPostBinding(parserPool(), velocityEngine());
    }

    @Bean
    public HTTPArtifactBinding artifactBinding(ParserPool parserPool, VelocityEngine velocityEngine) {
        return new HTTPArtifactBinding(parserPool, velocityEngine, artifactResolutionProfile());
    }

    @Bean
    public SAMLArtifactResolutionProfile artifactResolutionProfile() {
        final SAMLArtifactResolutionProfileImpl samlArtifactResolutionProfile = new SAMLArtifactResolutionProfileImpl(httpClient());
        samlArtifactResolutionProfile.setProcessor(new SAMLProcessorImpl(Collections.singletonList(new HTTPSOAP11Binding(parserPool()))));
        return samlArtifactResolutionProfile;
    }

    @Bean
    public HttpClient httpClient() {
        return new HttpClient(new MultiThreadedHttpConnectionManager());
    }

    @Bean
    public VelocityEngine velocityEngine() {
        return VelocityFactory.getEngine();
    }

    @Bean
    public SAMLBootstrap samlBootstrap(SAMLConfigurer saml) {
        return new SAMLBootstrap(saml);
    }

    @Bean
    public SAMLConfigurer samlConfigurer() {
        return new SAMLConfigurer();
    }

}