我最近实现了一种方法，可以在SpringBoot中从JWT token获取用户名或电子邮件。

private String getUserName() {
         JwtAuthenticationToken authenticationToken = (JwtAuthenticationToken) SecurityContextHolder.getContext().getAuthentication();
    Jwt jwt = (Jwt) authenticationToken.getCredentials();
    String email = (String) jwt.getClaims().get("email");
    return email;
    }

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在您的情况下，@AuthenticationPrincipal将返回一个带有用户名的字符串，您可以通过在控制器中调用存储库并通过用户名获取用户，或者将存储库声明为@Bean并执行以下操作来获取用户：

public class JWTAuthorizationFilter extends BasicAuthenticationFilter {
//Get the repository
private UserRepository userRepository;
public JWTAuthorizationFilter(AuthenticationManager authManager) {
    super(authManager);
}
@Override
protected void doFilterInternal(HttpServletRequest req,
                                HttpServletResponse res,
                                FilterChain chain) throws IOException, ServletException {
    String header = req.getHeader(HEADER_STRING);
    if (header == null || !header.startsWith(TOKEN_PREFIX)) {
        chain.doFilter(req, res);
        return;
    }
    UsernamePasswordAuthenticationToken authentication = getAuthentication(req);
    SecurityContextHolder.getContext().setAuthentication(authentication);
    chain.doFilter(req, res);
}
private UsernamePasswordAuthenticationToken getAuthentication(HttpServletRequest request) {
    String token = request.getHeader(HEADER_STRING);
    if (token != null) {
        // parse the token.
        String user;
        try {
            user = Jwts.parser()
                    .setSigningKey(SECRET.getBytes())
                    .parseClaimsJws(token.replace(TOKEN_PREFIX, ""))
                    .getBody()
                    .getSubject();
        } catch (SignatureException e) {
            return null;
        }
        //Get your user
        UserEntity userEntity = this.userRepository.findByUsername(user);
        if (user != null) {
             //Seting in your AuthenticationPrincipal the user
             return new UsernamePasswordAuthenticationToken(userEntity, null, new ArrayList<>());
        }
        return null;
    }
    return null;
}
}

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检查是否使用了合适的注解，因为其中一个注解已被弃用。
Documentation - deprecated!
Documentation - fine!的
此外，请注意将username（String）解析为参数，而不是User type：
用于将Authentication.getPrincipal（）解析为方法参数的注解。
Check this topic as well!它可以帮助。
我不知道这是否是一个好的做法（我还没有被认为是Spring的“专业人士”），但在我的个人项目中，我从传递给控制器参数的HttpServletRequest对象中获取token。然后我使用JwtTokenUtil类，它有getUserFormToken(String token);方法来解析user/username。它看起来像这样：

控制器

@Autowired
TestService testService;
@Autowired
UserService userService;
@Autowired
private JwtTokenUtil jwtTokenUtil;
@RequestMapping(value="/test", method = RequestMethod.GET, produces = "application/json")
@ResponseBody
public List<Test> getTestsListByUserId(HttpServletRequest req){
    String token = req.getHeader(HEADER_STRING).replace(TOKEN_PREFIX,"");
    return testService.findByUserId(userService.findByUsername(jwtTokenUtil.getUsernameFromToken(token)));
}

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JwtTokenUtil

@Component
public class JwtTokenUtil implements Serializable {
public String getUsernameFromToken(String token) {
    return getClaimFromToken(token, Claims::getSubject);
}
public Date getExpirationDateFromToken(String token) {
    return getClaimFromToken(token, Claims::getExpiration);
}
public <T> T getClaimFromToken(String token, Function<Claims, T> claimsResolver) {
    final Claims claims = getAllClaimsFromToken(token);
    return claimsResolver.apply(claims);
}
private Claims getAllClaimsFromToken(String token) {
    return Jwts.parser()
            .setSigningKey(SIGNING_KEY)
            .parseClaimsJws(token)
            .getBody();
}
private Boolean isTokenExpired(String token) {
    final Date expiration = getExpirationDateFromToken(token);
    return expiration.before(new Date());
}
public String generateToken(User user) {
    return doGenerateToken(user.getUsername());
}
private String doGenerateToken(String subject) {
    Claims claims = Jwts.claims().setSubject(subject);
    claims.put("scopes", Arrays.asList(new SimpleGrantedAuthority("ROLE_ADMIN")));
    return Jwts.builder()
            .setClaims(claims)
            .setIssuer("issuer")
            .setIssuedAt(new Date(System.currentTimeMillis()))
            .setExpiration(new Date(System.currentTimeMillis() + ACCESS_TOKEN_VALIDITY_SECONDS*1000))
            .signWith(SignatureAlgorithm.HS256, SIGNING_KEY)
            .compact();
}
public Boolean validateToken(String token, UserDetails userDetails) {
    final String username = getUsernameFromToken(token);
    return (
           username.equals(userDetails.getUsername())
                   && !isTokenExpired(token));
    }
}

型
但我通常有不同的过滤器实现根据你的。如果你有兴趣-我用this教程和实现。

要检索自定义模型，我做以下事情：
从数据库中获取模型并将其设置为Principal。

private UsernamePasswordAuthenticationToken getAuthentication(HttpServletRequest request) {
        String token = request.getHeader(HEADER_STRING);
        if (token != null) {
            // parse the token.
            String user;
            try {
                user = Jwts.parser()
                        .setSigningKey(SECRET.getBytes())
                        .parseClaimsJws(token.replace(TOKEN_PREFIX, ""))
                        .getBody()
                        .getSubject();
            } catch (SignatureException e) {
                return null;
            }
            // Get user model
            ApplicationUser userModel = userRepository.findByUsername(user);
            // Set it
            if (user != null && userModel != null) return new UsernamePasswordAuthenticationToken(userModel, null, new ArrayList<>());
            return null;
        }
        return null;
    }

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然后在控制器中使用@AuthenticationPrincipal注解检索。

public ApplicationUser getCurrentUser(@AuthenticationPrincipal ApplicationUser user) {
    return user;
}

型

如果这仍然是实际的，我刚才回答了类似的问题here
要点是从header中取出authorization token：

HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
    String token = request.getHeader("Authorization").split(" ")[1];

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然后你就可以解码得到你需要的零件。

现在你可以做到这一点，它很容易和更简单：

public User getCurrentUser() {
        Authentication authenticationToken = SecurityContextHolder.getContext().getAuthentication();
        return (User)authenticationToken.getPrincipal();
    }

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