Spring Boot OAuth2配置报错：缺失ClientRegistrationRepository Bean

1. 排查OAuth客户端配置完整性 #

启动报错的核心原因是oauth2Login()配置需要ClientRegistrationRepository bean读取OAuth客户端注册信息（如GitHub的Client ID/Secret），这个类属于OAuth客户端场景必需组件，并非服务端专用。

检查你的application.yml或application.properties是否正确配置了GitHub OAuth信息：

# application.yml示例
spring:
  security:
    oauth2:
      client:
        registration:
          github:
            client-id: 你的GitHub客户端ID
            client-secret: 你的GitHub客户端密钥
            scope: read:user,user:email

只要配置正确，Spring Boot会自动创建ClientRegistrationRepository的实现类bean，无需手动定义。

2. 替换废弃配置方式 #

WebSecurityConfigurerAdapter已被废弃，推荐使用SecurityFilterChain Bean的方式配置Spring Security，可避免自动配置失效问题，代码如下：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpStatus;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.HttpStatusEntryPoint;

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            // 配置访问权限：首页、错误页、静态资源公开，其余接口需认证
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/", "/error", "/webjars/**").permitAll()
                .anyRequest().authenticated()
            )
            // 未认证请求返回401状态码
            .exceptionHandling(ex -> ex
                .authenticationEntryPoint(new HttpStatusEntryPoint(HttpStatus.UNAUTHORIZED))
            )
            // 启用OAuth2登录流程
            .oauth2Login();
            
        return http.build();
    }
}

使用该配置后，只要GitHub OAuth配置正确，应用即可正常启动，同时首页/会对未认证用户开放。

3. 极简方案：仅开放首页访问 #

若你仅需实现首页公开，无需自定义异常处理逻辑，可简化配置：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.web.SecurityFilterChain;

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/", "/index.html", "/webjars/**").permitAll()
                .anyRequest().authenticated()
            )
            .oauth2Login();
            
        return http.build();
    }
}

内容的提问来源于stack exchange，提问作者nightblade9