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在现代Web应用中,用户认证和授权是一个非常重要的环节。传统的Session-based认证方式虽然简单易用,但在分布式系统中存在一些局限性。为了解决这些问题,Token-based认证方式应运而生。本文将详细介绍如何使用Java实现Token登录验证,并重点介绍JWT(JSON Web Token)的使用。
Token是一种用于身份验证和授权的令牌。它通常是一个字符串,包含了用户的身份信息和其他相关数据。Token可以在客户端和服务器之间传递,用于验证用户的身份和权限。
JWT由三部分组成,分别是Header、Payload和Signature,它们之间用.分隔。
在开始之前,确保你已经安装了以下工具:
使用Spring Initializr创建一个新的Spring Boot项目,选择以下依赖:
在pom.xml中添加JWT依赖:
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt</artifactId>
<version>0.9.1</version>
</dependency>
创建一个User实体类和一个UserRepository接口:
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String password;
// Getters and Setters
}
public interface UserRepository extends JpaRepository<User, Long> {
User findByUsername(String username);
}
创建一个UserDetailsService实现类:
@Service
public class CustomUserDetailsService implements UserDetailsService {
@Autowired
private UserRepository userRepository;
@Override
public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
User user = userRepository.findByUsername(username);
if (user == null) {
throw new UsernameNotFoundException("User not found");
}
return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());
}
}
创建一个JwtUtil类用于生成和验证JWT Token:
@Component
public class JwtUtil {
private String SECRET_KEY = "secret";
public String extractUsername(String token) {
return extractClaim(token, Claims::getSubject);
}
public Date extractExpiration(String token) {
return extractClaim(token, Claims::getExpiration);
}
public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
final Claims claims = extractAllClaims(token);
return claimsResolver.apply(claims);
}
private Claims extractAllClaims(String token) {
return Jwts.parser().setSigningKey(SECRET_KEY).parseClaimsJws(token).getBody();
}
private Boolean isTokenExpired(String token) {
return extractExpiration(token).before(new Date());
}
public String generateToken(UserDetails userDetails) {
Map<String, Object> claims = new HashMap<>();
return createToken(claims, userDetails.getUsername());
}
private String createToken(Map<String, Object> claims, String subject) {
return Jwts.builder().setClaims(claims).setSubject(subject).setIssuedAt(new Date(System.currentTimeMillis()))
.setExpiration(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 10))
.signWith(SignatureAlgorithm.HS256, SECRET_KEY).compact();
}
public Boolean validateToken(String token, UserDetails userDetails) {
final String username = extractUsername(token);
return (username.equals(userDetails.getUsername()) && !isTokenExpired(token));
}
}
创建一个JwtRequestFilter类用于拦截请求并验证JWT Token:
@Component
public class JwtRequestFilter extends OncePerRequestFilter {
@Autowired
private CustomUserDetailsService userDetailsService;
@Autowired
private JwtUtil jwtUtil;
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
throws ServletException, IOException {
final String authorizationHeader = request.getHeader("Authorization");
String username = null;
String jwt = null;
if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
jwt = authorizationHeader.substring(7);
username = jwtUtil.extractUsername(jwt);
}
if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
UserDetails userDetails = this.userDetailsService.loadUserByUsername(username);
if (jwtUtil.validateToken(jwt, userDetails)) {
UsernamePasswordAuthenticationToken usernamePasswordAuthenticationToken = new UsernamePasswordAuthenticationToken(
userDetails, null, userDetails.getAuthorities());
usernamePasswordAuthenticationToken
.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
SecurityContextHolder.getContext().setAuthentication(usernamePasswordAuthenticationToken);
}
}
chain.doFilter(request, response);
}
}
在SecurityConfig类中配置Spring Security,保护API端点:
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
@Autowired
private CustomUserDetailsService userDetailsService;
@Autowired
private JwtRequestFilter jwtRequestFilter;
@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
auth.userDetailsService(userDetailsService);
}
@Override
protected void configure(HttpSecurity http) throws Exception {
http.csrf().disable()
.authorizeRequests().antMatchers("/authenticate").permitAll()
.anyRequest().authenticated()
.and().sessionManagement()
.sessionCreationPolicy(SessionCreationPolicy.STATELESS);
http.addFilterBefore(jwtRequestFilter, UsernamePasswordAuthenticationFilter.class);
}
@Override
@Bean
public AuthenticationManager authenticationManagerBean() throws Exception {
return super.authenticationManagerBean();
}
@Bean
public PasswordEncoder passwordEncoder() {
return NoOpPasswordEncoder.getInstance();
}
}
localStorage或sessionStorage中。为了实现Token的自动刷新,可以在Token即将过期时,生成一个新的Token并返回给客户端。客户端在收到新的Token后,替换旧的Token。
本文详细介绍了如何使用Java实现Token登录验证,并重点介绍了JWT的使用。通过Token-based认证方式,可以有效解决传统Session-based认证在分布式系统中的局限性。希望本文能帮助你更好地理解和应用Token登录验证技术。
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