if (StringUtils.hasText(token) && token.startsWith("Bearer ")) { return token.substring(7); // 去除 "Bearer " 前缀 }这个是干嘛

这段代码是用于在请求中提取 JWT（JSON Web Token）的内容，并去除 JWT 前缀 "Bearer "。

首先，通过调用 `StringUtils.hasText(token)`，判断 `token` 是否为非空且不为纯空格的字符串。

接着，通过调用 `token.startsWith("Bearer ")` 来检查 `token` 是否以 "Bearer " 作为前缀。JWT 的标准格式是以 "Bearer " 作为前缀的，例如 "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."。

如果 `token` 非空且以 "Bearer " 作为前缀，则执行 `token.substring(7)`，即去除前缀 "Bearer "，返回除去前缀后的 JWT 内容。

例如，如果 `token` 是 "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."，那么经过这段代码处理后，返回的结果将是 "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."，即去除了 "Bearer " 前缀。

这段代码的作用是将请求中包含的 JWT 提取出来，并去除前缀，以便后续进行 JWT 的验证或其他处理。

相关问题

springboot用户登录返回token

好的，你可以尝试使用Spring Security和JWT组合来实现用户登录返回token的功能。

1. 首先，在pom.xml文件中添加以下依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

<dependency>
   <groupId>io.jsonwebtoken</groupId>
   <artifactId>jjwt</artifactId>
   <version>0.9.1</version>
</dependency>

2. 创建一个配置类，用于配置Spring Security和JWT，例如：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private UserDetailsService userDetailsService;

    @Autowired
    private JwtAuthenticationEntryPoint unauthorizedHandler;

    @Bean
    public JwtAuthenticationFilter authenticationTokenFilterBean() throws Exception {
        return new JwtAuthenticationFilter();
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService).passwordEncoder(passwordEncoder());
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.cors().and().csrf().disable()
                .exceptionHandling().authenticationEntryPoint(unauthorizedHandler).and()
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
                .authorizeRequests()
                .antMatchers(HttpMethod.GET, "/").permitAll()
                .antMatchers(HttpMethod.POST, "/api/auth/**").permitAll()
                .anyRequest().authenticated();

        // Add our custom JWT security filter
        http.addFilterBefore(authenticationTokenFilterBean(), UsernamePasswordAuthenticationFilter.class);
    }

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

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

3. 创建一个JWT工具类，用于生成和解析token，例如：

@Component
public class JwtTokenProvider {

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

    @Value("${jwt.expiration}")
    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;
    }
}

4. 创建一个JWT认证过滤器，用于验证token，例如：

public class JwtAuthenticationFilter extends OncePerRequestFilter {

    @Autowired
    private JwtTokenProvider tokenProvider;

    @Autowired
    private CustomUserDetailsService customUserDetailsService;

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {
        try {
            String jwt = getJwtFromRequest(request);

            if (StringUtils.hasText(jwt) && tokenProvider.validateToken(jwt)) {
                Long userId = tokenProvider.getUserIdFromJWT(jwt);

                UserDetails userDetails = customUserDetailsService.loadUserById(userId);
                UsernamePasswordAuthenticationToken authentication = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());
                authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));

                SecurityContextHolder.getContext().setAuthentication(authentication);
            }
        } catch (Exception ex) {
            logger.error("Could not set user authentication in security context", ex);
        }

        filterChain.doFilter(request, response);
    }

    private String getJwtFromRequest(HttpServletRequest request) {
        String bearerToken = request.getHeader("Authorization");
        if (StringUtils.hasText(bearerToken) && bearerToken.startsWith("Bearer ")) {
            return bearerToken.substring(7, bearerToken.length());
        }
        return null;
    }
}

5. 创建一个控制器，用于处理用户登录请求，例如：

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

    @Autowired
    private AuthenticationManager authenticationManager;

    @Autowired
    private JwtTokenProvider tokenProvider;

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

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

        SecurityContextHolder.getContext().setAuthentication(authentication);

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

其中，LoginRequest是一个包含用户名和密码的请求对象，JwtAuthenticationResponse是一个包含JWT的响应对象。

6. 最后，在application.yml文件中添加以下配置：

jwt:
  secret: mySecretKey
  expiration: 86400000

其中，jwt.secret是用于签名的密钥，jwt.expiration是token的过期时间，以毫秒为单位。

springboot使用token实现登录验证接口

可以使用Spring Security和JWT（JSON Web Token）来实现基于token的登录验证接口。下面是一个简单的示例：

1. 添加依赖

在pom.xml中添加以下依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.0</version>
</dependency>

2. 配置Spring Security

在Spring Boot的配置类中添加以下代码：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private UserDetailsServiceImpl userDetailsService;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
            .authorizeRequests()
            .antMatchers("/api/auth/**").permitAll()
            .anyRequest().authenticated()
            .and()
            .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);
        http.addFilterBefore(authenticationJwtTokenFilter(), UsernamePasswordAuthenticationFilter.class);
    }

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

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

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

这个配置类禁用了CSRF保护，允许所有用户访问“/api/auth/**”接口，其余接口需要进行认证。它还使用“JwtAuthenticationFilter”类来验证token。

3. 实现UserDetailsService

创建一个UserDetailsService的实现类，用于从数据库或其他数据源中获取用户信息。例如：

@Service
public class UserDetailsServiceImpl implements UserDetailsService {

    @Autowired
    private UserRepository userRepository;

    @Override
    @Transactional
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.findByUsername(username)
                .orElseThrow(() -> new UsernameNotFoundException("User Not Found with username: " + username));

        return UserDetailsImpl.build(user);
    }
}

这里的“UserDetailsImpl”类是一个自定义的实现了UserDetails接口的类，用于封装用户信息。

4. 实现JwtUtils

创建一个JwtUtils类，用于生成和验证token。例如：

@Component
public class JwtUtils {
    @Value("${jwt.secret}")
    private String jwtSecret;

    @Value("${jwt.expirationMs}")
    private int jwtExpirationMs;

    public String generateJwtToken(Authentication authentication) {
        UserDetailsImpl userPrincipal = (UserDetailsImpl) authentication.getPrincipal();
        return Jwts.builder()
                .setSubject((userPrincipal.getUsername()))
                .setIssuedAt(new Date())
                .setExpiration(new Date((new Date()).getTime() + jwtExpirationMs))
                .signWith(SignatureAlgorithm.HS512, jwtSecret)
                .compact();
    }

    public boolean validateJwtToken(String authToken) {
        try {
            Jwts.parser().setSigningKey(jwtSecret).parseClaimsJws(authToken);
            return true;
        } catch (SignatureException e) {
            logger.error("Invalid JWT signature: {}", e.getMessage());
        } catch (MalformedJwtException e) {
            logger.error("Invalid JWT token: {}", e.getMessage());
        } catch (ExpiredJwtException e) {
            logger.error("JWT token is expired: {}", e.getMessage());
        } catch (UnsupportedJwtException e) {
            logger.error("JWT token is unsupported: {}", e.getMessage());
        } catch (IllegalArgumentException e) {
            logger.error("JWT claims string is empty: {}", e.getMessage());
        }

        return false;
    }

    public String getUsernameFromJwtToken(String token) {
        return Jwts.parser().setSigningKey(jwtSecret).parseClaimsJws(token).getBody().getSubject();
    }
}

这里的“jwt.secret”和“jwt.expirationMs”分别是用于生成token的密钥和过期时间（以毫秒为单位）。

5. 实现JwtAuthenticationFilter

创建一个JwtAuthenticationFilter类，用于在每个请求上验证token。例如：

public class JwtAuthenticationFilter extends OncePerRequestFilter {

    @Autowired
    private JwtUtils jwtUtils;

    @Autowired
    private UserDetailsServiceImpl userDetailsService;

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {
        try {
            String jwt = parseJwt(request);
            if (jwt != null && jwtUtils.validateJwtToken(jwt)) {
                String username = jwtUtils.getUsernameFromJwtToken(jwt);

                UserDetails userDetails = userDetailsService.loadUserByUsername(username);
                UsernamePasswordAuthenticationToken authentication = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());
                authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));

                SecurityContextHolder.getContext().setAuthentication(authentication);
            }
        } catch (Exception e) {
            logger.error("Cannot set user authentication: {}", e.getMessage());
        }

        filterChain.doFilter(request, response);
    }

    private String parseJwt(HttpServletRequest request) {
        String headerAuth = request.getHeader("Authorization");

        if (StringUtils.hasText(headerAuth) && headerAuth.startsWith("Bearer ")) {
            return headerAuth.substring(7, headerAuth.length());
        }

        return null;
    }
}

这个过滤器将从请求头中获取token，并使用JwtUtils类来验证token。如果token有效，则将用户信息设置为Spring Security的上下文中的认证信息。

6. 创建登录接口

创建一个登录接口，用于验证用户并生成token。例如：

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

    @Autowired
    private AuthenticationManager authenticationManager;

    @Autowired
    private JwtUtils jwtUtils;

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

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

        SecurityContextHolder.getContext().setAuthentication(authentication);

        String jwt = jwtUtils.generateJwtToken(authentication);

        return ResponseEntity.ok(new JwtResponse(jwt));
    }
}

这个接口将使用AuthenticationManager来验证用户信息，并使用JwtUtils类来生成token。如果验证成功，则返回一个包含token的JwtResponse对象。

7. 测试接口

现在可以测试接口了。使用POST方法向“/api/auth/signin”发送以下JSON数据：

{
    "username": "your_username",
    "password": "your_password"
}

如果验证成功，则会返回一个包含token的JSON响应。以后，可以在每个请求中将token作为“Authorization”请求头的值发送。