<!-- 스프링부트 시큐리티 기본 lib -->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-security</artifactId>
</dependency>

<!-- 구글 로그인등 oauth2를 사용하기 위한 lib -->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-oauth2-client</artifactId>
</dependency>

<!-- 테스트 Lib -->    
<dependency>
	<groupId>org.springframework.security</groupId>
	<artifactId>spring-security-test</artifactId>
	<scope>test</scope>
</dependency>

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;

import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;


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

	@Bean
	public BCryptPasswordEncoder encodePwd() {
		return new BCryptPasswordEncoder();
	}

	@Override
	protected void configure(HttpSecurity http) throws Exception {
		//로그아웃은 디폴트 값으로 /logout 을 사용한다

		http.csrf().disable();
		http.authorizeRequests()
			.antMatchers("/dash/**").access("hasRole('ROLE_ADMIN')")
			.anyRequest().permitAll()
		.and()
			.formLogin()
			.loginPage("/login")
			.loginProcessingUrl("/loginProc")
			.defaultSuccessUrl("/")
		.and()
			.oauth2Login()
			.loginPage("/login")
		.and()
			.logout()
			.logoutSuccessUrl("/login")
			.invalidateHttpSession(true);
	}
}

import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;

import com.apt.proptech.domain.User;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.userdetails.UserDetails;


import lombok.Data;
import org.springframework.security.oauth2.core.user.OAuth2User;


@Data
public class PrincipalDetails implements UserDetails, OAuth2User {

	// 프로젝트에서 별도로 구현한 User
	private User user;
	private Map<String, Object> attributes;

	//일반 로그인시 사용
	public PrincipalDetails(User user) {
		super();
		this.user = user;
	}

	// OAuth2.0 로그인시 사용
	public PrincipalDetails(User user, Map<String, Object> attributes) {
		this.user = user;
		this.attributes = attributes;
	}

	@Override
	public String getPassword() {
		return user.getPassword();
	}

	@Override
	public String getUsername() {
		return user.getUsername();
	}

	@Override
	public boolean isAccountNonExpired() {
		return true;
	}

	@Override
	public boolean isAccountNonLocked() {
		return true;
	}

	//계정 비밀번호가 만료되지 않았는지 반환
	@Override
	public boolean isCredentialsNonExpired() {
		return true;
	}

	// 계정이 활성화(사용가능) 상태 인지 반환
	@Override
	public boolean isEnabled() {
		return true;
	}

	@Override
	public Map<String, Object> getAttributes() {
		return attributes;
	}

	@Override
	public Collection<? extends GrantedAuthority> getAuthorities() {
		Collection<GrantedAuthority> collection = new ArrayList<GrantedAuthority>();
		collection.add(()->{ return user.getUserRole().name();});
		return collection;
	}


	@Override
	public String getName() {
		return null;
	}
}

import com.apt.proptech.domain.oauth.PrincipalDetails;
import com.apt.proptech.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
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;


@Service
public class PrincipalDetailsService implements UserDetailsService{

	@Autowired
	private UserRepository userRepository;

	@Override
	public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {

		return new PrincipalDetails(userRepository.findByUsername(username).orElseThrow(()->new UsernameNotFoundException(username)));
	}

}

spring:
  security:
    oauth2:
      client:
        registration:
          google: # /oauth2/authorization/google 이 주소를 동작하게 한다.
            client-id: ENC(3P13X0MEc7WH3Hchx8s4PEGFNbGL7s0QOeISXx+sxYlX1TByJ/HnXJHERDPmywLCbhlFoxp1yczmkj3g7IWUReIB2vHRkaLF/9AuaA5jnWwEexSVlyTRNw==)
            client-secret: ENC(SccKsp2Z/9tA3396ftHJRpjlPwTE7Hz7ushjsfTySrQ31L65u0X8dg==)
            scope:
            - email
            - profile

// OAuth2.0 제공자들 마다 응답해주는 속성값이 달라서 공통으로 만들어준다.
public interface OAuth2UserInfo {
	String getProviderId();
	String getProvider();
	String getEmail();
	String getName();
}

@Service
public class PrincipalOauth2UserService extends DefaultOAuth2UserService {

	@Autowired
	private UserRepository userRepository;

	static final Logger LOGGER = LoggerFactory.getLogger(PrincipalOauth2UserService.class);


	// userRequest 는 code를 받아서 accessToken을 응답 받은 객체
	@Override
	public OAuth2User loadUser(OAuth2UserRequest userRequest) throws OAuth2AuthenticationException {
		// google의 회원 프로필 조회
		OAuth2User oAuth2User = super.loadUser(userRequest);

		return processOAuth2User(userRequest, oAuth2User);
	}

	private OAuth2User processOAuth2User(OAuth2UserRequest userRequest, OAuth2User oAuth2User) {

        // oAuth2값 지정 -> 제공자에 따라 값이 달라짐
		OAuth2UserInfo oAuth2UserInfo = new oAuth2UserInfo();

		oAuth2UserInfo.setProviderId(oAuth2User.getAttributes().get("sub") );
        oAuth2UserInfo.setProvider("google" );
        oAuth2UserInfo.setName(oAuth2User.getAttributes().get("name")  );
        oAuth2UserInfo.setEmail( oAuth2User.getAttributes().get("email"));

       Optional<User> userOptional = userRepository.findByProviderAndProviderId(oAuth2UserInfo.getProvider(), oAuth2UserInfo.getProviderId());
		User user;
		if (userOptional.isPresent()) {
			user = userOptional.get();
			// user가 존재하면 update 해주기
			user.setEmail(oAuth2UserInfo.getEmail());
			userRepository.save(user);
		} else {
			// user의 패스워드가 null이기 때문에 OAuth 유저는 일반적인 로그인을 할 수 없음.
			user = User.builder()
					.username(oAuth2UserInfo.getProvider() + "_" + oAuth2UserInfo.getProviderId())
					.email(oAuth2UserInfo.getEmail())
					.userRole(UserRole.ROLE_USER)
					.provider(oAuth2UserInfo.getProvider())
					.providerId(oAuth2UserInfo.getProviderId())
					.build();
			userRepository.save(user);
		}

		return new PrincipalDetails(user, oAuth2User.getAttributes());
	}
}

<body onload="document.f.username.focus();">
    <h3>Login with Username and Password</h3>
    <form name="f" action="/login" method="POST">
        <table>
            <tbody>
                <tr>
                    <td>User:</td>
                    <td><input type="text" name="username" value=""></td>
                </tr>
                <tr>
                    <td>Password:</td>
                    <td><input type="password" name="password"></td>
                </tr>
                <tr>
                    <td colspan="2"><input name="submit" type="submit" value="Login"></td>
                </tr>
            </tbody>
        </table>
   <a href="/oauth2/authorization/google" class="btn btn-google btn-user btn-block">
	<i class="fab fa-google fa-fw"></i> Login with Google
   </a>
    </form>
</body>

@GetMapping("/login")
public String loginView( ){
	return "login/login";
}

@GetMapping("/userinfo")
@ResponseBody
public String user(@AuthenticationPrincipal PrincipalDetails principal) {
        LOGGER.debug("principal : "+principal.getName());

        // iterator 순차 출력 해보기
        Iterator<? extends GrantedAuthority> iter = principal.getAuthorities().iterator();
        while (iter.hasNext()) {
            GrantedAuthority auth = iter.next();
            System.out.println(auth.getAuthority());
        }

        return "유저 페이지입니다.";
    }


@GetMapping(value = "/logout")
public String logoutPage(HttpServletRequest request, HttpServletResponse response) {
        new SecurityContextLogoutHandler().logout(request, response, SecurityContextHolder.getContext().getAuthentication());
        return "redirect:/login";
    }