這期內容當中小編將會給大家帶來有關如何在Springboot中使用Spring Security實現一個JWT認證，文章內容豐富且以專業的角度為大家分析和敘述，閱讀完這篇文章希望大家可以有所收獲。
Spring Security作為成熟且強大的安全框架，得到許多大廠的青睞。而作為前后端分離的SSO方案，JWT也在許多項目中應用。本文將介紹如何通過Spring Security實現JWT認證。
用戶與服務器交互大概如下：
客戶端獲取JWT，一般通過POST方法把用戶名/密碼傳給server；
服務端接收到客戶端的請求后，會檢驗用戶名/密碼是否正確，如果正確則生成JWT并返回；不正確則返回錯誤；
客戶端拿到JWT后，在有效期內都可以通過JWT來訪問資源了，一般把JWT放在請求頭；一次獲取，多次使用；
服務端校驗JWT是否合法，合法則允許客戶端正常訪問，不合法則返回401。
我們把要整合的Spring Security和JWT加入到項目的依賴中去：
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <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>
JWT工具類起碼要具有以下功能：
根據用戶信息生成JWT；
校驗JWT是否合法，如是否被篡改、是否過期等；
從JWT中解析用戶信息，如用戶名、權限等；
具體代碼如下：
@Component
public class JwtTokenProvider {
@Autowired JwtProperties jwtProperties;
@Autowired
private CustomUserDetailsService userDetailsService;
private String secretKey;
@PostConstruct
protected void init() {
secretKey = Base64.getEncoder().encodeToString(jwtProperties.getSecretKey().getBytes());
}
public String createToken(String username, List<String> roles) {
Claims claims = Jwts.claims().setSubject(username);
claims.put("roles", roles);
Date now = new Date();
Date validity = new Date(now.getTime() + jwtProperties.getValidityInMs());
return Jwts.builder()//
.setClaims(claims)//
.setIssuedAt(now)//
.setExpiration(validity)//
.signWith(SignatureAlgorithm.HS256, secretKey)//
.compact();
}
public Authentication getAuthentication(String token) {
UserDetails userDetails = this.userDetailsService.loadUserByUsername(getUsername(token));
return new UsernamePasswordAuthenticationToken(userDetails, "", userDetails.getAuthorities());
}
public String getUsername(String token) {
return Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token).getBody().getSubject();
}
public String resolveToken(HttpServletRequest req) {
String bearerToken = req.getHeader("Authorization");
if (bearerToken != null && bearerToken.startsWith("Bearer ")) {
return bearerToken.substring(7);
}
return null;
}
public boolean validateToken(String token) {
try {
Jws<Claims> claims = Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token);
if (claims.getBody().getExpiration().before(new Date())) {
return false;
}
return true;
} catch (JwtException | IllegalArgumentException e) {
throw new InvalidJwtAuthenticationException("Expired or invalid JWT token");
}
}
}工具類還實現了另一個功能：從HTTP請求頭中獲取JWT。
Filter是Security處理的關鍵，基本上都是通過Filter來攔截請求的。首先從請求頭取出JWT，然后校驗JWT是否合法，如果合法則取出Authentication保存在SecurityContextHolder里。如果不合法，則做異常處理。
public class JwtTokenAuthenticationFilter extends GenericFilterBean {
private JwtTokenProvider jwtTokenProvider;
public JwtTokenAuthenticationFilter(JwtTokenProvider jwtTokenProvider) {
this.jwtTokenProvider = jwtTokenProvider;
}
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
try {
String token = jwtTokenProvider.resolveToken(request);
if (token != null && jwtTokenProvider.validateToken(token)) {
Authentication auth = jwtTokenProvider.getAuthentication(token);
if (auth != null) {
SecurityContextHolder.getContext().setAuthentication(auth);
}
}
} catch (InvalidJwtAuthenticationException e) {
response.setStatus(HttpStatus.UNAUTHORIZED.value());
response.getWriter().write("Invalid token");
response.getWriter().flush();
return;
}
filterChain.doFilter(req, res);
}
}對于異常處理，使用@ControllerAdvice是不行的，應該這個是Filter，在這里拋的異常還沒有到DispatcherServlet，無法處理。所以Filter要自己做異常處理：
catch (InvalidJwtAuthenticationException e) {
response.setStatus(HttpStatus.UNAUTHORIZED.value());
response.getWriter().write("Invalid token");
response.getWriter().flush();
return;
}最后的return不能省略，因為已經要把輸出的內容給Response了，沒有必要再往后傳遞，否則報錯
java.lang.IllegalStateException: getWriter() has already been called
JWT需要配置一個密鑰來加密，同時還要配置JWT令牌的有效期。
@Configuration
@ConfigurationProperties(prefix = "pkslow.jwt")
public class JwtProperties {
private String secretKey = "pkslow.key";
private long validityInMs = 3600_000;
//getter and setter
}Spring Security的整個框架還是比較復雜的，簡化后大概如下圖所示：
它是通過一連串的Filter來進行安全管理。細節這里先不展開講。
這個配置也可以理解為是FilterChain的配置，可以不用理解，代碼很好懂它做了什么：
@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {
@Autowired
JwtTokenProvider jwtTokenProvider;
@Bean
@Override
public AuthenticationManager authenticationManagerBean() throws Exception {
return super.authenticationManagerBean();
}
@Bean
public PasswordEncoder passwordEncoder() {
return NoOpPasswordEncoder.getInstance();
}
@Override
protected void configure(HttpSecurity http) throws Exception {
http
.httpBasic().disable()
.csrf().disable()
.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS)
.and()
.authorizeRequests()
.antMatchers("/auth/login").permitAll()
.antMatchers(HttpMethod.GET, "/admin").hasRole("ADMIN")
.antMatchers(HttpMethod.GET, "/user").hasRole("USER")
.anyRequest().authenticated()
.and()
.apply(new JwtSecurityConfigurer(jwtTokenProvider));
}
}這里通過HttpSecurity配置了哪些請求需要什么權限才可以訪問。
/auth/login用于登陸獲取JWT，所以都能訪問；
/admin只有ADMIN用戶才可以訪問；
/user只有USER用戶才可以訪問。
而之前實現的Filter則在下面配置使用：
public class JwtSecurityConfigurer extends SecurityConfigurerAdapter<DefaultSecurityFilterChain, HttpSecurity> {
private JwtTokenProvider jwtTokenProvider;
public JwtSecurityConfigurer(JwtTokenProvider jwtTokenProvider) {
this.jwtTokenProvider = jwtTokenProvider;
}
@Override
public void configure(HttpSecurity http) throws Exception {
JwtTokenAuthenticationFilter customFilter = new JwtTokenAuthenticationFilter(jwtTokenProvider);
http.exceptionHandling()
.authenticationEntryPoint(new JwtAuthenticationEntryPoint())
.and()
.addFilterBefore(customFilter, UsernamePasswordAuthenticationFilter.class);
}
}通常在Spring Security的世界里，都是通過實現UserDetailsService來獲取UserDetails的。
@Component
public class CustomUserDetailsService implements UserDetailsService {
private UserRepository users;
public CustomUserDetailsService(UserRepository users) {
this.users = users;
}
@Override
public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
return this.users.findByUsername(username)
.orElseThrow(() -> new UsernameNotFoundException("Username: " + username + " not found"));
}
}對于UserRepository，可以從數據庫中讀取，或者其它用戶管理中心。為了方便，我使用Map放了兩個用戶：
@Repository
public class UserRepository {
private static final Map<String, User> allUsers = new HashMap<>();
@Autowired
private PasswordEncoder passwordEncoder;
@PostConstruct
protected void init() {
allUsers.put("pkslow", new User("pkslow", passwordEncoder.encode("123456"), Collections.singletonList("ROLE_ADMIN")));
allUsers.put("user", new User("user", passwordEncoder.encode("123456"), Collections.singletonList("ROLE_USER")));
}
public Optional<User> findByUsername(String username) {
return Optional.ofNullable(allUsers.get(username));
}
}完成代碼編寫后，我們來測試一下：
（1）無JWT訪問，失敗
curl http://localhost:8080/admin
{"timestamp":"2021-02-06T05:45:06.385+0000","status":403,"error":"Forbidden","message":"Access Denied","path":"/admin"}
$ curl http://localhost:8080/user
{"timestamp":"2021-02-06T05:45:16.438+0000","status":403,"error":"Forbidden","message":"Access Denied","path":"/user"}（2）admin獲取JWT，密碼錯誤則失敗，密碼正確則成功
$ curl http://localhost:8080/auth/login -X POST -d '{"username":"pkslow","password":"xxxxxx"}' -H 'Content-Type: application/json'
{"timestamp":"2021-02-06T05:47:16.254+0000","status":403,"error":"Forbidden","message":"Access Denied","path":"/auth/login"}
$ curl http://localhost:8080/auth/login -X POST -d '{"username":"pkslow","password":"123456"}' -H 'Content-Type: application/json'
eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJwa3Nsb3ciLCJyb2xlcyI6WyJST0xFX0FETUlOIl0sImlhdCI6MTYxMjU5MDYxNCwiZXhwIjoxNjEyNTkxMjE0fQ.d4Gi50aaOsHHqpM0d8Mh2960otnZf7rlE3x6xSfakVo（3）admin帶JWT訪問/admin，成功；訪問/user失敗
$ curl http://localhost:8080/admin -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJwa3Nsb3ciLCJyb2xlcyI6WyJST0xFX0FETUlOIl0sImlhdCI6MTYxMjU5MDYxNCwiZXhwIjoxNjEyNTkxMjE0fQ.d4Gi50aaOsHHqpM0d8Mh2960otnZf7rlE3x6xSfakVo'
you are admin
$ curl http://localhost:8080/user -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJwa3Nsb3ciLCJyb2xlcyI6WyJST0xFX0FETUlOIl0sImlhdCI6MTYxMjU5MDYxNCwiZXhwIjoxNjEyNTkxMjE0fQ.d4Gi50aaOsHHqpM0d8Mh2960otnZf7rlE3x6xSfakVo'
{"timestamp":"2021-02-06T05:51:23.099+0000","status":403,"error":"Forbidden","message":"Forbidden","path":"/user"}（4）使用過期的JWT訪問，失敗
$ curl http://localhost:8080/admin -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJwa3Nsb3ciLCJyb2xlcyI6WyJST0xFX0FETUlOIl0sImlhdCI6MTYxMjU5MDQ0OSwiZXhwIjoxNjEyNTkwNTA5fQ.CSaubE4iJcYATbLmbb59aNFU1jNCwDFHUV3zIakPU64' Invalid token
上述就是小編為大家分享的如何在Springboot中使用Spring Security實現一個JWT認證了，如果剛好有類似的疑惑，不妨參照上述分析進行理解。如果想知道更多相關知識，歡迎關注億速云行業資訊頻道。
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