概述
眾所周知使用 JWT 做權限驗證，相比 Session 的優點是，Session 需要占用大量服務器內存，并且在多服務器時就會涉及到共享 Session 問題，在手機等移動端訪問時比較麻煩
而 JWT 無需存儲在服務器，不占用服務器資源（也就是無狀態的），用戶在登錄后拿到 Token 后，訪問需要權限的請求時附上 Token（一般設置在Http請求頭），JWT 不存在多服務器共享的問題，也沒有手機移動端訪問問題，若為了提高安全，可將 Token 與用戶的 IP 地址綁定起來
前端流程
用戶通過 AJAX 進行登錄得到一個 Token
之后訪問需要權限請求時附上 Token 進行訪問
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Title</title> <script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script> <script type="application/javascript"> var header = ""; function login() { $.post("http://localhost:8080/auth/login", { username: $("#username").val(), password: $("#password").val() }, function (data) { console.log(data); header = data; }) } function toUserPageBtn() { $.ajax({ type: "get", url: "http://localhost:8080/userpage", beforeSend: function (request) { request.setRequestHeader("Authorization", header); }, success: function (data) { console.log(data); } }); } </script></head><body> <fieldset> <legend>Please Login</legend> <label>UserName</label><input type="text" id="username"> <label>Password</label><input type="text" id="password"> <input type="button" onclick="login()" value="Login"> </fieldset> <button id="toUserPageBtn" onclick="toUserPageBtn()">訪問UserPage</button></body></html>后端流程（Spring Boot + Spring Security + JJWT）
思路：
編寫用戶實體類，并插入一條數據
User（用戶）實體類
@Data@Entitypublic class User { @Id @GeneratedValue private int id; private String name; private String password; @ManyToMany(cascade = {CascadeType.REFRESH}, fetch = FetchType.EAGER) @JoinTable(name = "user_role", joinColumns = {@JoinColumn(name = "uid", referencedColumnName = "id")}, inverseJoinColumns = {@JoinColumn(name = "rid", referencedColumnName = "id")}) private List<Role> roles;} Role（權限）實體類
@Data@Entitypublic class Role { @Id @GeneratedValue private int id; private String name; @ManyToMany(mappedBy = "roles") private List<User> users;}插入數據
User 表
| id | name | password |
|---|---|---|
| 1 | linyuan | 123 |
Role 表
| id | name |
|---|---|
| 1 | USER |
User_ROLE 表
| uid | rid |
|---|---|
| 1 | 1 |
Dao 層接口，通過用戶名獲取數據，返回值為 Java8 的 Optional 對象
public interface UserRepository extends Repository<User,Integer> { Optional<User> findByName(String name);}編寫 LoginDTO，用于與前端之間數據傳輸
@Datapublic class LoginDTO implements Serializable { @NotBlank(message = "用戶名不能為空") private String username; @NotBlank(message = "密碼不能為空") private String password;}編寫 Token 生成工具，利用 JJWT 庫創建，一共三個方法：生成 Token（返回String）、解析 Token（返回Authentication認證對象）、驗證 Token（返回布爾值）
@Componentpublic class JWTTokenUtils { private final Logger log = LoggerFactory.getLogger(JWTTokenUtils.class); private static final String AUTHORITIES_KEY = "auth"; private String secretKey; //簽名密鑰 private long tokenValidityInMilliseconds; //失效日期 private long tokenValidityInMillisecondsForRememberMe; //（記住我）失效日期 @PostConstruct public void init() { this.secretKey = "Linyuanmima"; int secondIn1day = 1000 * 60 * 60 * 24; this.tokenValidityInMilliseconds = secondIn1day * 2L; this.tokenValidityInMillisecondsForRememberMe = secondIn1day * 7L; } private final static long EXPIRATIONTIME = 432_000_000; //創建Token public String createToken(Authentication authentication, Boolean rememberMe){ String authorities = authentication.getAuthorities().stream() //獲取用戶的權限字符串，如 USER,ADMIN .map(GrantedAuthority::getAuthority) .collect(Collectors.joining(",")); long now = (new Date()).getTime(); //獲取當前時間戳 Date validity; //存放過期時間 if (rememberMe){ validity = new Date(now + this.tokenValidityInMilliseconds); }else { validity = new Date(now + this.tokenValidityInMillisecondsForRememberMe); } return Jwts.builder() //創建Token令牌 .setSubject(authentication.getName()) //設置面向用戶 .claim(AUTHORITIES_KEY,authorities) //添加權限屬性 .setExpiration(validity) //設置失效時間 .signWith(SignatureAlgorithm.HS512,secretKey) //生成簽名 .compact(); } //獲取用戶權限 public Authentication getAuthentication(String token){ System.out.println("token:"+token); Claims claims = Jwts.parser() //解析Token的payload .setSigningKey(secretKey) .parseClaimsJws(token) .getBody(); Collection<? extends GrantedAuthority> authorities = Arrays.stream(claims.get(AUTHORITIES_KEY).toString().split(",")) //獲取用戶權限字符串 .map(SimpleGrantedAuthority::new) .collect(Collectors.toList()); //將元素轉換為GrantedAuthority接口集合 User principal = new User(claims.getSubject(), "", authorities); return new UsernamePasswordAuthenticationToken(principal, "", authorities); } //驗證Token是否正確 public boolean validateToken(String token){ try { Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token); //通過密鑰驗證Token return true; }catch (SignatureException e) { //簽名異常 log.info("Invalid JWT signature."); log.trace("Invalid JWT signature trace: {}", e); } catch (MalformedJwtException e) { //JWT格式錯誤 log.info("Invalid JWT token."); log.trace("Invalid JWT token trace: {}", e); } catch (ExpiredJwtException e) { //JWT過期 log.info("Expired JWT token."); log.trace("Expired JWT token trace: {}", e); } catch (UnsupportedJwtException e) { //不支持該JWT log.info("Unsupported JWT token."); log.trace("Unsupported JWT token trace: {}", e); } catch (IllegalArgumentException e) { //參數錯誤異常 log.info("JWT token compact of handler are invalid."); log.trace("JWT token compact of handler are invalid trace: {}", e); } return false; }}實現 UserDetails 接口，代表用戶實體類，在我們的 User 對象上在進行包裝，包含了權限等性質，可以供 Spring Security 使用
public class MyUserDetails implements UserDetails{ private User user; public MyUserDetails(User user) { this.user = user; } @Override public Collection<? extends GrantedAuthority> getAuthorities() { List<Role> roles = user.getRoles(); List<GrantedAuthority> authorities = new ArrayList<>(); StringBuilder sb = new StringBuilder(); if (roles.size()>=1){ for (Role role : roles){ authorities.add(new SimpleGrantedAuthority(role.getName())); } return authorities; } return AuthorityUtils.commaSeparatedStringToAuthorityList(""); } @Override public String getPassword() { return user.getPassword(); } @Override public String getUsername() { return user.getName(); } @Override public boolean isAccountNonExpired() { return true; } @Override public boolean isAccountNonLocked() { return true; } @Override public boolean isCredentialsNonExpired() { return true; } @Override public boolean isEnabled() { return true; }}實現 UserDetailsService 接口，該接口僅有一個方法，用來獲取 UserDetails，我們可以從數據庫中獲取 User 對象，然后將其包裝成 UserDetails 并返回
@Servicepublic class MyUserDetailsService implements UserDetailsService { @Autowired UserRepository userRepository; @Override public UserDetails loadUserByUsername(String s) throws UsernameNotFoundException { //從數據庫中加載用戶對象 Optional<User> user = userRepository.findByName(s); //調試用，如果值存在則輸出下用戶名與密碼 user.ifPresent((value)->System.out.println("用戶名:"+value.getName()+" 用戶密碼："+value.getPassword())); //若值不再則返回null return new MyUserDetails(user.orElse(null)); }}編寫過濾器，用戶如果攜帶 Token 則獲取 Token，并根據 Token 生成 Authentication 認證對象，并存放到 SecurityContext 中，供 Spring Security 進行權限控制
public class JwtAuthenticationTokenFilter extends GenericFilterBean { private final Logger log = LoggerFactory.getLogger(JwtAuthenticationTokenFilter.class); @Autowired private JWTTokenUtils tokenProvider; @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { System.out.println("JwtAuthenticationTokenFilter"); try { HttpServletRequest httpReq = (HttpServletRequest) servletRequest; String jwt = resolveToken(httpReq); if (StringUtils.hasText(jwt) && this.tokenProvider.validateToken(jwt)) { //驗證JWT是否正確 Authentication authentication = this.tokenProvider.getAuthentication(jwt); //獲取用戶認證信息 SecurityContextHolder.getContext().setAuthentication(authentication); //將用戶保存到SecurityContext } filterChain.doFilter(servletRequest, servletResponse); }catch (ExpiredJwtException e){ //JWT失效 log.info("Security exception for user {} - {}", e.getClaims().getSubject(), e.getMessage()); log.trace("Security exception trace: {}", e); ((HttpServletResponse) servletResponse).setStatus(HttpServletResponse.SC_UNAUTHORIZED); } } private String resolveToken(HttpServletRequest request){ String bearerToken = request.getHeader(WebSecurityConfig.AUTHORIZATION_HEADER); //從HTTP頭部獲取TOKEN if (StringUtils.hasText(bearerToken) && bearerToken.startsWith("Bearer ")){ return bearerToken.substring(7, bearerToken.length()); //返回Token字符串，去除Bearer } String jwt = request.getParameter(WebSecurityConfig.AUTHORIZATION_TOKEN); //從請求參數中獲取TOKEN if (StringUtils.hasText(jwt)) { return jwt; } return null; }}編寫 LoginController，用戶通過用戶名、密碼訪問 /auth/login，通過 LoginDTO 對象接收，創建一個 Authentication 對象，代碼中為 UsernamePasswordAuthenticationToken，判斷對象是否存在，通過 AuthenticationManager 的 authenticate 方法對認證對象進行驗證，AuthenticationManager 的實現類 ProviderManager 會通過 AuthentionProvider（認證處理） 進行驗證，默認 ProviderManager 調用 DaoAuthenticationProvider 進行認證處理，DaoAuthenticationProvider 中會通過 UserDetailsService（認證信息來源） 獲取 UserDetails ，若認證成功則返回一個包含權限的 Authention，然后通過 SecurityContextHolder.getContext().setAuthentication() 設置到 SecurityContext 中，根據 Authentication 生成 Token，并返回給用戶
@RestControllerpublic class LoginController { @Autowired private UserRepository userRepository; @Autowired private AuthenticationManager authenticationManager; @Autowired private JWTTokenUtils jwtTokenUtils; @RequestMapping(value = "/auth/login",method = RequestMethod.POST) public String login(@Valid LoginDTO loginDTO, HttpServletResponse httpResponse) throws Exception{ //通過用戶名和密碼創建一個 Authentication 認證對象，實現類為 UsernamePasswordAuthenticationToken UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(loginDTO.getUsername(),loginDTO.getPassword()); //如果認證對象不為空 if (Objects.nonNull(authenticationToken)){ userRepository.findByName(authenticationToken.getPrincipal().toString()) .orElseThrow(()->new Exception("用戶不存在")); } try { //通過 AuthenticationManager（默認實現為ProviderManager）的authenticate方法驗證 Authentication 對象 Authentication authentication = authenticationManager.authenticate(authenticationToken); //將 Authentication 綁定到 SecurityContext SecurityContextHolder.getContext().setAuthentication(authentication); //生成Token String token = jwtTokenUtils.createToken(authentication,false); //將Token寫入到Http頭部 httpResponse.addHeader(WebSecurityConfig.AUTHORIZATION_HEADER,"Bearer "+token); return "Bearer "+token; }catch (BadCredentialsException authentication){ throw new Exception("密碼錯誤"); } }}編寫 Security 配置類，繼承 WebSecurityConfigurerAdapter，重寫 configure 方法
@Configuration@EnableWebSecurity@EnableGlobalMethodSecurity(prePostEnabled = true)public class WebSecurityConfig extends WebSecurityConfigurerAdapter { public static final String AUTHORIZATION_HEADER = "Authorization"; public static final String AUTHORIZATION_TOKEN = "access_token"; @Autowired private UserDetailsService userDetailsService; @Override protected void configure(AuthenticationManagerBuilder auth) throws Exception { auth //自定義獲取用戶信息 .userDetailsService(userDetailsService) //設置密碼加密 .passwordEncoder(passwordEncoder()); } @Override protected void configure(HttpSecurity http) throws Exception { //配置請求訪問策略 http //關閉CSRF、CORS .cors().disable() .csrf().disable() //由于使用Token，所以不需要Session .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS) .and() //驗證Http請求 .authorizeRequests() //允許所有用戶訪問首頁 與 登錄 .antMatchers("/","/auth/login").permitAll() //其它任何請求都要經過認證通過 .anyRequest().authenticated() //用戶頁面需要用戶權限 .antMatchers("/userpage").hasAnyRole("USER") .and() //設置登出 .logout().permitAll(); //添加JWT filter 在 http .addFilterBefore(genericFilterBean(), UsernamePasswordAuthenticationFilter.class); } @Bean public PasswordEncoder passwordEncoder() { return new BCryptPasswordEncoder(); } @Bean public GenericFilterBean genericFilterBean() { return new JwtAuthenticationTokenFilter(); }}編寫用于測試的Controller
@RestControllerpublic class UserController { @PostMapping("/login") public String login() { return "login"; } @GetMapping("/") public String index() { return "hello"; } @GetMapping("/userpage") public String httpApi() { System.out.println(SecurityContextHolder.getContext().getAuthentication().getPrincipal()); return "userpage"; } @GetMapping("/adminpage") public String httpSuite() { return "userpage"; }}案例源碼下載
總結
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