从角度前端访问spring boot restcontroller时出现的问题

我有以下设置:

我的控制器:

@RequestMapping("/project")
@RestController
public class ProjectController {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    ProjectService projectService;

    @CrossOrigin
    @PostMapping(value = "/createProject")
    public ResponseEntity createProject(@RequestBody ProjectDto projectJsonString) {
        return ResponseEntity.ok(HttpStatus.OK);
    }
}

在我的 .service.ts 以下内容:

this.http.post('http://localhost:8080/project/createProject', JSON.stringify(project)).
      subscribe( (res) => {
        this.logger.info('Response: ' + res);
      });

我的DTO:

public class ProjectDto {
    private String projectName;
    private String projectNumber;
    private String projectArea;
    private String managerName;
    private String managerShorthand;
}

但是,当我将应用程序构建到jar文件并执行它时,在执行api调用时会出现以下错误:

HttpErrorResponse {headers: HttpHeaders, status: 415, statusText: "OK", url: "http://localhost:8080/project/createProject", ok: false, …}
error:
error: "Unsupported Media Type"
message: "Content type 'text/plain;charset=UTF-8' not supported"
path: "/project/createProject"
status: 415
timestamp: "2018-12-10T21:41:26.036+0000"

当我 curl 它。有人能告诉我我做错了什么吗?