问题描述：当使用Angular作为前端框架，Spring Boot作为后端框架时，无法从Spring Boot接收JWT令牌。

解决方法：

1. 在Angular应用中，确保在发送请求时，将JWT令牌作为请求头的一部分发送给后端。可以使用Angular的HttpClient模块来发送HTTP请求，示例如下：

import { HttpClient, HttpHeaders } from '@angular/common/http';

@Injectable()
export class AuthService {
  constructor(private http: HttpClient) {}

  login(username: string, password: string) {
    const headers = new HttpHeaders().set('Authorization', 'Bearer ' + token);
    return this.http.post('/api/login', { username, password }, { headers });
  }
}

在上述示例中，Authorization 请求头使用 Bearer 方案来传递JWT令牌。

2. 在Spring Boot后端应用中，确保能够正确解析JWT令牌并验证其有效性。可以使用Spring Security和JWT库来处理JWT令牌。示例如下：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Autowired
    private JwtTokenProvider jwtTokenProvider;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
            .authorizeRequests()
            .antMatchers("/api/login").permitAll()
            .anyRequest().authenticated()
            .and()
            .apply(new JwtConfigurer(jwtTokenProvider));
    }
}

@Component
public class JwtConfigurer extends SecurityConfigurerAdapter {
    private JwtTokenProvider jwtTokenProvider;

    public JwtConfigurer(JwtTokenProvider jwtTokenProvider) {
        this.jwtTokenProvider = jwtTokenProvider;
    }

    @Override
    public void configure(HttpSecurity http) throws Exception {
        JwtTokenFilter customFilter = new JwtTokenFilter(jwtTokenProvider);
        http.addFilterBefore(customFilter, UsernamePasswordAuthenticationFilter.class);
    }
}

@Component
public class JwtTokenFilter extends OncePerRequestFilter {
    private JwtTokenProvider jwtTokenProvider;

    public JwtTokenFilter(JwtTokenProvider jwtTokenProvider) {
        this.jwtTokenProvider = jwtTokenProvider;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
            throws ServletException, IOException {
        String token = jwtTokenProvider.resolveToken(request);
        if (token != null && jwtTokenProvider.validateToken(token)) {
            Authentication auth = jwtTokenProvider.getAuthentication(token);
            SecurityContextHolder.getContext().setAuthentication(auth);
        }
        chain.doFilter(request, response);
    }
}

@Component
public class JwtTokenProvider {
    private static final String SECRET_KEY = "your_secret_key_here";

    public String createToken(String username, List roles) {
        // 生成JWT令牌的代码
    }

    public Authentication getAuthentication(String token) {
        // 从JWT令牌中提取用户信息并创建认证对象的代码
    }

    public boolean validateToken(String token) {
        // 验证JWT令牌的有效性的代码
    }

    public String resolveToken(HttpServletRequest request) {
        // 从请求中解析JWT令牌的代码
    }
}

上述示例中，JwtTokenProvider 类负责生成、验证和解析JWT令牌；JwtTokenFilter 类负责从请求中提取JWT令牌并进行验证；JwtConfigurer 类负责将JwtTokenFilter 添加到Spring Security的过滤器链中。

请根据自己的实际情况进行相应的调整和配置，确保配置正确。