Spring webflux中Controller层错误处理错误

Question

所以我想实现保存用户的功能 首先我检查用户是否存在 如果存在则抛出异常 否则保存用户 但是当我从服务层抛出异常时.flatMap(user -> Mono.error(new IllegalArgumentException("User Exists with email " + user.getEmail())))

@Service
@RequiredArgsConstructor
public class AppUserService {

    private final AppUserRepository appUserRepository;

    public Flux<AppUser> getAllUsers() {
        return appUserRepository.findAll();
    }

    public Mono<AppUser> saveUser(AppUser appUser) {
        return getUser(appUser.getEmail())
                .flatMap(user -> Mono.error(new IllegalArgumentException("User Exists with email " + user.getEmail())))
                .switchIfEmpty(Mono.defer(() -> appUserRepository.save(appUser))).cast(AppUser.class).log();
    }

    public Mono<AppUser> getUser(String email) {
        return appUserRepository.findFirstByEmail(email);
    }
}

如果我像 .onErrorResume(error -> ServerResponse.badRequest().bodyValue(error)) 那样处理它，则在控制器层中

@RestController
@RequiredArgsConstructor
@RequestMapping("/user")
public class AppUserController {

    private final AppUserService appUserService;
    private final PasswordEncoder encoder;

    @GetMapping
    public Flux<AppUser> getAllUsers(@RequestHeader("email") String email) {
        return appUserService.getAllUsers();
    }

    @PostMapping
    @CrossOrigin
    public Mono<ResponseEntity<Object>> saveUser(@RequestBody Mono<AppUser> appUserMono) {
        return appUserMono
        .doOnSuccess(appUser -> appUser.setPassword(encoder.encode(appUser.getPassword())))
        .subscribeOn(Schedulers.parallel())
        .flatMap(appUserService::saveUser)
        .flatMap(savedAppUser -> ResponseEntity.created(URI.create("/user/" + savedAppUser.getId())).build())
        .onErrorResume(error -> Response entity.badRequest().bodyValue(error))
        .log();
    }

}

它在控制台上抛出一个错误

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.springframework.web.reactive.function.server.DefaultEntityResponseBuilder$DefaultEntityResponse and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS)

并向客户端返回 200

我做错了什么

阅读错误后，它似乎得到了一个空值 但是如果我在onErrorResume(error -> ..) 处调试流程，则错误变量有错误 不明白为什么它仍然抛出杰克逊错误 是不是因为杰克逊无法订阅 ServerResponse 或类似的东西

Answer 1

您的代码中存在一些问题。

以下是让它运行的方法（没有存储库）：

package test;

import lombok.Builder;
import lombok.Data;

@Data
@Builder
public class AppUser {
  private String id;

  private String username;

  private String firstName;

  private String password;

  private String email;
}

@Service
@RequiredArgsConstructor
public class AppUserService {

  public Mono<AppUser> saveUser(AppUser appUser) {
    return getUser(appUser.getEmail())
        .flatMap(user -> Mono.<AppUser>error(
            new IllegalArgumentException("User Exists with email " + user.getEmail())))
        .switchIfEmpty(Mono.defer(() -> Mono.just(AppUser.builder().username("mustafa").build())));
  }

  public Mono<AppUser> getUser(String email) {
//    return Mono.defer(() -> Mono.just(AppUser.builder().email(email).build()));
    return Mono.defer(Mono::empty);
  }
}

@RestController
@RequiredArgsConstructor
@RequestMapping("/user")
public class AppUserController {

  private final AppUserService appUserService;

  @PostMapping
  @CrossOrigin
  public Mono<ResponseEntity<AppUser>> saveUser(@RequestBody Mono<AppUser> appUserMono,
                                                @RequestHeader("email") String email) {
    return appUserMono
        .subscribeOn(Schedulers.parallel())
        .flatMap(appUserService::saveUser)
        .flatMap(savedAppUser -> Mono.just(
            ResponseEntity.created(URI.create("/user/" + savedAppUser.getId())).body(savedAppUser)))
        .onErrorResume(error -> Mono.just(ResponseEntity.badRequest().build()))
        .log();
  }
}

您的控制器的返回类型是Mono<ResponseEntity<AppUser>>，但您返回的是ServerResponse。我修复了这个问题并从您的服务代码中删除了演员表。

您可以通过注释/取消注释 getUser 正文来尝试生成 400 或有效结果。

也许更清晰的方式来编写电子邮件检查逻辑是使用旧的 if/else 语句：

  public Mono<AppUser> saveUser(AppUser appUser) {
    if (emailExists(appUser.getEmail())) {
      return Mono.error(new IllegalArgumentException("User Exists with email "
          + appUser.getEmail()));
    } else {
      return Mono.just(AppUser.builder().username("mustafa").build());
    }
  }