用springboot框架编写一个用户登录案例

好的，下面是使用Spring Boot框架编写用户登录案例的步骤：

1. 创建一个Spring Boot项目，并添加相应的依赖。

2. 创建一个用户实体类，包含用户名和密码属性。

@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false, unique = true)
    private String username;

    @Column(nullable = false)
    private String password;

    // 省略getter和setter方法
}

3. 创建一个用户登录表单类，包含用户名和密码属性。

public class LoginForm {
    @NotBlank
    private String username;

    @NotBlank
    private String password;

    // 省略getter和setter方法
}

4. 创建一个用户控制器类，处理用户登录请求。

@RestController
@RequestMapping("/api/auth")
public class AuthController {

    @Autowired
    private AuthenticationManager authenticationManager;

    @Autowired
    private JwtTokenProvider jwtTokenProvider;

    @Autowired
    private UserService userService;

    @PostMapping("/signin")
    public ResponseEntity<?> authenticateUser(@Valid @RequestBody LoginForm loginRequest) {

        Authentication authentication = authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(
                        loginRequest.getUsername(),
                        loginRequest.getPassword()
                )
        );

        SecurityContextHolder.getContext().setAuthentication(authentication);

        String jwt = jwtTokenProvider.generateToken(authentication);
        return ResponseEntity.ok(new JwtAuthenticationResponse(jwt));
    }

    // 省略其他方法
}

5. 创建一个用户服务类，处理用户数据的CRUD操作。

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public Optional<User> findByUsername(String username) {
        return userRepository.findByUsername(username);
    }

    @Override
    public void save(User user) {
        userRepository.save(user);
    }
}

6. 创建一个JWT Token提供者类，用于生成和验证Token。

@Component
public class JwtTokenProvider {

    @Value("${app.jwtSecret}")
    private String jwtSecret;

    @Value("${app.jwtExpirationInMs}")
    private int jwtExpirationInMs;

    public String generateToken(Authentication authentication) {

        UserPrincipal userPrincipal = (UserPrincipal) authentication.getPrincipal();

        Date now = new Date();
        Date expiryDate = new Date(now.getTime() + jwtExpirationInMs);

        return Jwts.builder()
                .setSubject(Long.toString(userPrincipal.getId()))
                .setIssuedAt(new Date())
                .setExpiration(expiryDate)
                .signWith(SignatureAlgorithm.HS512, jwtSecret)
                .compact();
    }

    public Long getUserIdFromJWT(String token) {
        Claims claims = Jwts.parser()
                .setSigningKey(jwtSecret)
                .parseClaimsJws(token)
                .getBody();

        return Long.parseLong(claims.getSubject());
    }

    public boolean validateToken(String authToken) {
        try {
            Jwts.parser().setSigningKey(jwtSecret).parseClaimsJws(authToken);
            return true;
        } catch (SignatureException ex) {
            logger.error("Invalid JWT signature");
        } catch (MalformedJwtException ex) {
            logger.error("Invalid JWT token");
        } catch (ExpiredJwtException ex) {
            logger.error("Expired JWT token");
        } catch (UnsupportedJwtException ex) {
            logger.error("Unsupported JWT token");
        } catch (IllegalArgumentException ex) {
            logger.error("JWT claims string is empty.");
        }
        return false;
    }
}

7. 创建一个JWT身份验证响应类，用于在登录成功后返回Token给客户端。

public class JwtAuthenticationResponse {
    private String accessToken;
    private String tokenType = "Bearer";

    public JwtAuthenticationResponse(String accessToken) {
        this.accessToken = accessToken;
    }

    public String getAccessToken() {
        return accessToken;
    }

    public void setAccessToken(String accessToken) {
        this.accessToken = accessToken;
    }

    public String getTokenType() {
        return tokenType;
    }

    public void setTokenType(String tokenType) {
        this.tokenType = tokenType;
    }
}

8. 创建一个Spring Security配置类，用于配置安全策略和过滤器链。

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(
        securedEnabled = true,
        jsr250Enabled = true,
        prePostEnabled = true
)
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private CustomUserDetailsService customUserDetailsService;

    @Autowired
    private JwtAuthenticationEntryPoint unauthorizedHandler;

    @Bean
    public JwtAuthenticationFilter jwtAuthenticationFilter() {
        return new JwtAuthenticationFilter();
    }

    @Override
    public void configure(AuthenticationManagerBuilder authenticationManagerBuilder) throws Exception {
        authenticationManagerBuilder
                .userDetailsService(customUserDetailsService)
                .passwordEncoder(passwordEncoder());
    }

    @Bean(BeanIds.AUTHENTICATION_MANAGER)
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }

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

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.cors().and().csrf().disable()
                .exceptionHandling().authenticationEntryPoint(unauthorizedHandler).and()
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
                .authorizeRequests().antMatchers("/",
                "/favicon.ico",
                "/**/*.png",
                "/**/*.gif",
                "/**/*.svg",
                "/**/*.jpg",
                "/**/*.html",
                "/**/*.css",
                "/**/*.js").permitAll()
                .antMatchers("/api/auth/**").permitAll()
                .anyRequest().authenticated();

        // 添加JWT身份验证过滤器
        http.addFilterBefore(jwtAuthenticationFilter(), UsernamePasswordAuthenticationFilter.class);
    }
}

以上就是使用Spring Boot框架编写用户登录案例的基本步骤，您可以根据自己的需求进行修改和扩展。