Spring Security basic auth for sign in - spring-boot

Question

I am new to springboot security.And i just find that it is quite hard to follow the latest version since some of the method has already outdated.So i just follow on some of the tutorials to work on the jwt and authentication with mysql.I have problem on the use of the basic auth for generating the token when it is integrated to my own model.Here are my code.
Tokenservice:
#Service
public class TokenService {
private final JwtEncoder encoder;
private PasswordEncoder passwordEncoder;
public TokenService(JwtEncoder jwtEncoder, PasswordEncoder passwordEncoder) {
this.encoder = jwtEncoder;
this.passwordEncoder = passwordEncoder;
}
#Autowired
private JpaUserrepository jpaUserrepository;
private Authentication auth;
public String generateToken (Authentication authentication){
Instant now=Instant.now();
String scope=authentication.getAuthorities().stream() //Stream<capture of ? extends GrantedAuthority >
.map(GrantedAuthority::getAuthority)
.collect(Collectors.joining(" "));
JwtClaimsSet claims = JwtClaimsSet.builder()
.issuer(authentication.getName())
.issuedAt(now)
.expiresAt(now.plus(1, ChronoUnit.HOURS))
.claim("scope",scope).build();
return this.encoder.encode(JwtEncoderParameters.from((claims))).getTokenValue();
}
public String signup(JpaUser jpaUser) {
System.out.println(jpaUserrepository.findByUsername(jpaUser.getUsername()));
if(jpaUserrepository.findByUsername(jpaUser.getUsername()).isPresent())
{return "repeated username";}
jpaUserrepository.save(new JpaUser(jpaUser.getUsername(),passwordEncoder.encode(jpaUser.getPassword()),jpaUser.getEmail(),jpaUser.getRoles()));
return "sign up success";
}
}
I want to sign up which can return the token,but the required type of generatedtoken method is authentication (Basic Auth) but i have no idea to convert my Jpauser model to authentication interphase.
Here is Jpauser model:
#Entity
#Table(name = "JpaUser")
public class JpaUser {
#Id #GeneratedValue
private Long id;
private String username;
private String password;
private String email;
private String roles;
public JpaUser() {}
public JpaUser(String username, String password,String email, String roles) {
this.username = username;
this.password = password;
this.email=email;
this.roles = roles;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public void setPassword(String password) {
this.password = password;
}
public String getRoles() {
return roles;
}
public void setRoles(String roles) {
this.roles = roles;
}
#Override
public String toString() {
return "SecurityUser{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", email='" + email + '\'' +
", roles='" + roles + '\'' +
'}';
}
}
My securityconfig:
#Bean
public SecurityFilterChain securityfilterchain(HttpSecurity http) throws Exception {
return http
//if used csrf.ignoringAntMatchers -->prevent the attack from cross-origin
//.csrf(csrf -> csrf.disable())
.csrf(csrf -> csrf.ignoringAntMatchers("/shownews/**","/getnews/**","/token","/signup"))
.authorizeRequests(auth-> auth
.antMatchers("/shownews/**").permitAll()
.antMatchers("/getnews/**").permitAll()
.anyRequest().authenticated())
.oauth2ResourceServer(OAuth2ResourceServerConfigurer::jwt)
.sessionManagement(session -> session.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
//Link to the jpauserservice to check whether the authentication valid (similar to authentication manager)
.userDetailsService(myUserDetailsService)
.headers(headers -> headers.frameOptions().sameOrigin())
.httpBasic(Customizer.withDefaults())
.formLogin().and()
.build();
}
#Bean
JwtDecoder jwtDecoder(){
return NimbusJwtDecoder.withPublicKey(rsakeys.publicKey()).build();
}
In fact, i am quite loss when i learn this topic since i think the doc is quite hard to understand .I am just wondering if there any materials that are more easy to understand amd modifymy code?