顺便说一句，我之前给出的解决方案可行，但我最初的意图是个坏主意：错误就是错误，不应该在名义流量上处理。像 Feign 那样抛出异常，并用 @ExceptionHandler 处理它是在 Spring MVC 世界中更好的方式。
所以两个解决方案：
- 为
FeignException 添加一个@ExceptionHandler
- 使用
ErrorDecoder 配置FeignClient 以转换业务层知道的异常中的错误（并且已经提供@ExceptionHandler）
我更喜欢第二种解决方案，因为收到的错误消息结构可能会从一个客户端更改为另一个，因此您可以通过每个客户端的错误解码从这些错误中提取更细粒度的数据。
FeignClient with conf（抱歉 feign-form 引入的噪音）
@FeignClient(value = "uaa", configuration = OauthFeignClient.Config.class)
public interface OauthFeignClient {
@RequestMapping(
value = "/oauth/token",
method = RequestMethod.POST,
consumes = MULTIPART_FORM_DATA_VALUE,
produces = APPLICATION_JSON_VALUE)
DefaultOAuth2AccessToken token(Map<String, ?> formParams);
@Configuration
class Config {
@Value("${oauth.client.password}")
String oauthClientPassword;
@Autowired
private ObjectFactory<HttpMessageConverters> messageConverters;
@Bean
public Encoder feignFormEncoder() {
return new SpringFormEncoder(new SpringEncoder(messageConverters));
}
@Bean
public Decoder springDecoder() {
return new ResponseEntityDecoder(new SpringDecoder(messageConverters));
}
@Bean
public Contract feignContract() {
return new SpringMvcContract();
}
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor("web-client", oauthClientPassword);
}
@Bean
public ErrorDecoder uaaErrorDecoder(Decoder decoder) {
return (methodKey, response) -> {
try {
OAuth2Exception uaaException = (OAuth2Exception) decoder.decode(response, OAuth2Exception.class);
return new SroException(
uaaException.getHttpErrorCode(),
uaaException.getOAuth2ErrorCode(),
Arrays.asList(uaaException.getSummary()));
} catch (Exception e) {
return new SroException(
response.status(),
"Authorization server responded with " + response.status() + " but failed to parse error payload",
Arrays.asList(e.getMessage()));
}
};
}
}
}
常见业务异常
public class SroException extends RuntimeException implements Serializable {
public final int status;
public final List<String> errors;
public SroException(final int status, final String message, final Collection<String> errors) {
super(message);
this.status = status;
this.errors = Collections.unmodifiableList(new ArrayList<>(errors));
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SroException)) return false;
SroException sroException = (SroException) o;
return status == sroException.status &&
Objects.equals(super.getMessage(), sroException.getMessage()) &&
Objects.equals(errors, sroException.errors);
}
@Override
public int hashCode() {
return Objects.hash(status, super.getMessage(), errors);
}
}
错误处理程序（从ResponseEntityExceptionHandler 扩展中提取）
@ExceptionHandler({SroException.class})
public ResponseEntity<Object> handleSroException(SroException ex) {
return new SroError(ex).toResponse();
}
错误响应 DTO
@XmlRootElement
public class SroError implements Serializable {
public final int status;
public final String message;
public final List<String> errors;
public SroError(final int status, final String message, final Collection<String> errors) {
this.status = status;
this.message = message;
this.errors = Collections.unmodifiableList(new ArrayList<>(errors));
}
public SroError(final SroException e) {
this.status = e.status;
this.message = e.getMessage();
this.errors = Collections.unmodifiableList(e.errors);
}
protected SroError() {
this.status = -1;
this.message = null;
this.errors = null;
}
public ResponseEntity<Object> toResponse() {
return new ResponseEntity(this, HttpStatus.valueOf(this.status));
}
public ResponseEntity<Object> toResponse(HttpHeaders headers) {
return new ResponseEntity(this, headers, HttpStatus.valueOf(this.status));
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SroError)) return false;
SroError sroException = (SroError) o;
return status == sroException.status &&
Objects.equals(message, sroException.message) &&
Objects.equals(errors, sroException.errors);
}
@Override
public int hashCode() {
return Objects.hash(status, message, errors);
}
}
Feign 客户端使用请注意如何透明地处理错误（无尝试/捕获），这要归功于 @ControllerAdvice 和 @ExceptionHandler({SroException.class})
@RestController
@RequestMapping("/uaa")
public class AuthenticationController {
private static final BearerToken REVOCATION_TOKEN = new BearerToken("", 0L);
private final OauthFeignClient oauthFeignClient;
private final int refreshTokenValidity;
@Autowired
public AuthenticationController(
OauthFeignClient oauthFeignClient,
@Value("${oauth.ttl.refresh-token}") int refreshTokenValidity) {
this.oauthFeignClient = oauthFeignClient;
this.refreshTokenValidity = refreshTokenValidity;
}
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) {
Map<String, String> formData = new HashMap<>();
formData.put("grant_type", "password");
formData.put("client_id", "web-client");
formData.put("username", userCredentials.username);
formData.put("password", userCredentials.password);
formData.put("scope", "openid");
DefaultOAuth2AccessToken response = oauthFeignClient.token(formData);
return ResponseEntity.ok(new LoginTokenPair(
new BearerToken(response.getValue(), response.getExpiresIn()),
new BearerToken(response.getRefreshToken().getValue(), refreshTokenValidity)));
}
@PostMapping("/logout")
public ResponseEntity<LoginTokenPair> revokeTokens() {
return ResponseEntity
.ok(new LoginTokenPair(REVOCATION_TOKEN, REVOCATION_TOKEN));
}
@PostMapping("/refresh")
public ResponseEntity<BearerToken> refreshToken(@RequestHeader("refresh_token") String refresh_token) {
Map<String, String> formData = new HashMap<>();
formData.put("grant_type", "refresh_token");
formData.put("client_id", "web-client");
formData.put("refresh_token", refresh_token);
formData.put("scope", "openid");
DefaultOAuth2AccessToken response = oauthFeignClient.token(formData);
return ResponseEntity.ok(new BearerToken(response.getValue(), response.getExpiresIn()));
}
}