概述
- 使用 JWT 做权限验证，相比 Session 的优点是，Session 需要占用大量服务器内存，并且在多服务器时就会涉及到共享 Session 问题，在手机等移动端访问时比较麻烦
- 而 JWT 无需存储在服务器，不占用服务器资源（也就是无状态的），用户在登录后拿到 Token 后，访问需要权限的请求时附上 Token（一般设置在Http请求头），JWT 不存在多服务器共享的问题，也没有手机移动端访问问题，若为了提高安全，可将 Token 与用户的 IP 地址绑定起来
案例源码下载
前端流程
- 用户通过 AJAX 进行登录得到一个 Token
- 之后访问需要权限请求时附上 Token 进行访问
<!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()">访问UserPage</button>
</body>
</html>
后端流程（Spring Boot + Spring Security + JJWT）
思路：
创建用户、权限实体类与数据传输对象
编写 Dao 层接口，用于获取用户信息
实现 UserDetails（Security 支持的用户实体对象，包含权限信息）
实现 UserDetailsSevice（从数据库中获取用户信息，并包装成UserDetails）
编写 JWTToken 生成工具，用于生成、验证、解析 Token
配置 Security，配置请求处理 与 设置 UserDetails 获取方式为自定义的 UserDetailsSevice
编写 LoginController，接收用户登录名密码并进行验证，若验证成功返回 Token 给用户
编写过滤器，若用户请求头或参数中包含 Token 则解析，并生成 Authentication，绑定到 SecurityContext ，供 Security 使用
用户访问了需要权限的页面，却没附上正确的 Token，在过滤器处理时则没有生成 Authentication，也就不存在访问权限，则无法访问，否之访问成功
编写用户实体类，并插入一条数据
User（用户）实体类
@Data
@Entity
public 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（权限）实体类
@Data
@Entity
public class Role {
@Id
@GeneratedValue
private int id;
private String name;
@ManyToMany(mappedBy = "roles")
private List<User> users;
}
插入数据
User 表
| id | name | password |
|---|---|---|
| 1 | linyuan | 123 |
Role 表
| id | name |
|---|---|
| 1 | USER |
User_ROLE 表
| uid | rid |
|---|---|
| 1 | 1 |
Dao 层接口，通过用户名获取数据，返回值为 Java8 的 Optional 对象
public interface UserRepository extends Repository<User,Integer> {
Optional<User> findByName(String name);
}
编写 LoginDTO，用于与前端之间数据传输
@Data
public class LoginDTO implements Serializable {
@NotBlank(message = "用户名不能为空")
private String username;
@NotBlank(message = "密码不能为空")
private String password;
}
编写 Token 生成工具，利用 JJWT 库创建，一共三个方法：生成 Token（返回String）、解析 Token（返回Authentication认证对象）、验证 Token（返回布尔值）
@Component
public class JWTTokenUtils {
private final Logger log = LoggerFactory.getLogger(JWTTokenUtils.class);
private static final String AUTHORITIES_KEY = "auth";
private String secretKey; //签名密钥
private long tokenValidityInMilliseconds; //失效日期
private long tokenValidityInMillisecondsForRememberMe; //（记住我）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;
//创建Token
public String createToken(Authentication authentication, Boolean rememberMe){
String authorities = authentication.getAuthorities().stream() //获取用户的权限字符串，如 USER,ADMIN
.map(GrantedAuthority::getAuthority)
.collect(Collectors.joining(","));
long now = (new Date()).getTime(); //获取当前时间戳
Date validity; //存放过期时间
if (rememberMe){
validity = new Date(now + this.tokenValidityInMilliseconds);
}else {
validity = new Date(now + this.tokenValidityInMillisecondsForRememberMe);
}
return Jwts.builder() //创建Token令牌
.setSubject(authentication.getName()) //设置面向用户
.claim(AUTHORITIES_KEY,authorities) //添加权限属性
.setExpiration(validity) //设置失效时间
.signWith(SignatureAlgorithm.HS512,secretKey) //生成签名
.compact();
}
//获取用户权限
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(",")) //获取用户权限字符串
.map(SimpleGrantedAuthority::new)
.collect(Collectors.toList()); //将元素转换为GrantedAuthority接口集合
User principal = new User(claims.getSubject(), "", authorities);
return new UsernamePasswordAuthenticationToken(principal, "", authorities);
}
//验证Token是否正确
public boolean validateToken(String token){
try {
Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token); //通过密钥验证Token
return true;
}catch (SignatureException e) { //签名异常
log.info("Invalid JWT signature.");
log.trace("Invalid JWT signature trace: {}", e);
} catch (MalformedJwtException e) { //JWT格式错误
log.info("Invalid JWT token.");
log.trace("Invalid JWT token trace: {}", e);
} catch (ExpiredJwtException e) { //JWT过期
log.info("Expired JWT token.");
log.trace("Expired JWT token trace: {}", e);
} catch (UnsupportedJwtException e) { //不支持该JWT
log.info("Unsupported JWT token.");
log.trace("Unsupported JWT token trace: {}", e);
} catch (IllegalArgumentException e) { //参数错误异常
log.info("JWT token compact of handler are invalid.");
log.trace("JWT token compact of handler are invalid trace: {}", e);
}
return false;
}
}
实现 UserDetails 接口，代表用户实体类，在我们的 User 对象上在进行包装，包含了权限等性质，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;
}
}
实现 UserDetailsService 接口，该接口仅有一个方法，用来获取 UserDetails，我们可以从数据库中获取 User 对象，然后将其包装成 UserDetails 并返回
@Service
public class MyUserDetailsService implements UserDetailsService {
@Autowired
UserRepository userRepository;
@Override
public UserDetails loadUserByUsername(String s) throws UsernameNotFoundException {
//从数据库中加载用户对象
Optional<User> user = userRepository.findByName(s);
//调试用，如果值存在则输出下用户名与密码
user.ifPresent((value)->System.out.println("用户名:"+value.getName()+" 用户密码："+value.getPassword()));
//若值不再则返回null
return new MyUserDetails(user.orElse(null));
}
}
编写过滤器，用户如果携带 Token 则获取 Token，并根据 Token 生成 Authentication 认证对象，并存放到 SecurityContext 中，供 Spring Security 进行权限控制
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)) { //验证JWT是否正确
Authentication authentication = this.tokenProvider.getAuthentication(jwt); //获取用户认证信息
SecurityContextHolder.getContext().setAuthentication(authentication); //将用户保存到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); //从HTTP头部获取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); //从请求参数中获取TOKEN
if (StringUtils.hasText(jwt)) {
return jwt;
}
return null;
}
}
编写 LoginController，用户通过用户名、密码访问 /auth/login，通过 LoginDTO 对象接收，创建一个 Authentication 对象，代码中为 UsernamePasswordAuthenticationToken，判断对象是否存在，通过 AuthenticationManager 的 authenticate 方法对认证对象进行验证，AuthenticationManager 的实现类 ProviderManager 会通过 AuthentionProvider（认证处理） 进行验证，默认 ProviderManager 调用 DaoAuthenticationProvider 进行认证处理，DaoAuthenticationProvider 中会通过 UserDetailsService（认证信息来源） 获取 UserDetails ，若认证成功则返回一个包含权限的 Authention，然后通过 SecurityContextHolder.getContext().setAuthentication() 设置到 SecurityContext 中，根据 Authentication 生成 Token，并返回给用户
@RestController
public 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{
//通过用户名和密码创建一个 Authentication 认证对象，实现类为 UsernamePasswordAuthenticationToken
UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(loginDTO.getUsername(),loginDTO.getPassword());
//如果认证对象不为空
if (Objects.nonNull(authenticationToken)){
userRepository.findByName(authenticationToken.getPrincipal().toString())
.orElseThrow(()->new Exception("用户不存在"));
}
try {
//通过 AuthenticationManager（默认实现为ProviderManager）的authenticate方法验证 Authentication 对象
Authentication authentication = authenticationManager.authenticate(authenticationToken);
//将 Authentication 绑定到 SecurityContext
SecurityContextHolder.getContext().setAuthentication(authentication);
//生成Token
String token = jwtTokenUtils.createToken(authentication,false);
//将Token写入到Http头部
httpResponse.addHeader(WebSecurityConfig.AUTHORIZATION_HEADER,"Bearer "+token);
return "Bearer "+token;
}catch (BadCredentialsException authentication){
throw new Exception("密码错误");
}
}
}
编写 Security 配置类，继承 WebSecurityConfigurerAdapter，重写 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
//自定义获取用户信息
.userDetailsService(userDetailsService)
//设置密码加密
.passwordEncoder(passwordEncoder());
}
@Override
protected void configure(HttpSecurity http) throws Exception {
//配置请求访问策略
http
//关闭CSRF、CORS
.cors().disable()
.csrf().disable()
//由于使用Token，所以不需要Session
.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS)
.and()
//验证Http请求
.authorizeRequests()
//允许所有用户访问首页 与 登录
.antMatchers("/","/auth/login").permitAll()
//其它任何请求都要经过认证通过
.anyRequest().authenticated()
//用户页面需要用户权限
.antMatchers("/userpage").hasAnyRole("USER")
.and()
//设置登出
.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();
}
}
编写用于测试的Controller
@RestController
public 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";
}
}
