用后端服务替换内存中服务时的状态 404

Question

我创建了简单的 angular 7 应用程序，用于显示用户。首先，我能够成功地向用户显示内存中的 api 服务，我正试图将其替换为 Rest 服务。休息服务工作正常，因为我在休息客户端得到响应。当我用后端服务替换服务时，状态为 404。

export class UserService {
    private usersUrl = 'api/users';
    baseUrl: string = 'http://localhost:8080/listUsers';
    constructor(private http: HttpClient) {}

    /* getUsers() : Observable<User[]>{
      return this.http.get<User[]>(this.usersUrl);
    }*/

    getUsers(): Observable < User[] > {
        return this.http.get < User[] > (this.baseUrl);
    }
}

export class DisplayUsersComponent implements OnInit {

    users: User[];
    selectedUser: User;
    constructor(private userService: UserService) {}
    user: User = {
        userId: 1,
        userName: 'Jordan'
    };
    ngOnInit() {
        this.getUsers();
    }
    getUsers(): void {
        this.userService.getUsers().subscribe(users => this.users = users);

    }
    onSelect(user: User): void {
        this.selectedUser = user;
    }
}

DisplayUsersComponent 调用用户服务。它适用于 Api 服务，但不适用于实际后端 services.Please 指导我如何解决此问题。乔丹

Answer 1

An error 404 indicates that the URL you are trying to visit isn't found. If you are sure that the URL is correct, try after restarting your backend server & then visit your http://localhost:8080/listUsers to ensure that it is accessible.

建议： 你可以使用POSTMAN 测试您的 API。

用后端服务替换内存中服务时的状态 404

Status 404 when replacing In memory services with Back end services

angular-services

angular

angular7