0

请在下面查看我的代码。Java 代码似乎工作得很好，但是当我尝试访问它时localhost:8080给了我错误代码。404我想localhost 8080工作。如果您需要更多信息，请告诉我。

应用

@SpringBootApplication(exclude = { ErrorMvcAutoConfiguration.class })         
// exclude part is to elimnate whitelabel error
@EnableScheduling
public class Covid19TrackerApplication {

    public static void main(String[] args) {
        SpringApplication.run(Covid19TrackerApplication.class, args);
    }
}

控制器

@Controller
public class HomeController {
    
    CovidDataService covidDataService;
    
    @RequestMapping("/")
    public @ResponseBody String home(Model model) {
        model.addAttribute( "locationStats", covidDataService.getAllStats());
        return "home";
    } 

}

主要代码

@Service
public class CovidDataService {
    
    private static String Covid_Data_URL = "https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_global.csv";
    private List<LocationStats> allStats = new ArrayList<>();
    
    public List<LocationStats> getAllStats() {
        return allStats;
    }


    @PostConstruct//?
    @Scheduled(cron = "* * 1 * * *")    //????
    // * sec * min *hour and so on
    
    public void fetchCovidData() throws IOException, InterruptedException {
        List<LocationStats> newStats = new ArrayList<>(); // why we are adding this? To prevent user get an error while we are working on new data.
        HttpClient  client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(Covid_Data_URL))
                .build(); // uri = uniform resource identifier
        HttpResponse<String> httpResponse   = client.send(request, HttpResponse.BodyHandlers.ofString());
        StringReader csvBodyReader = new StringReader(httpResponse.body()); //StringReader needs to be imported
        
        Iterable<CSVRecord> records = CSVFormat.DEFAULT.withFirstRecordAsHeader().parse(csvBodyReader);  // parse(in) had error, we needed a "reader" instance.
        for (CSVRecord record : records) {
            LocationStats locationStat = new LocationStats();  //create an instance
            locationStat.setState(record.get("Province/State"));
            locationStat.setCountry(record.get("Country/Region"));
            locationStat.setLatestTotalCase(Integer.parseInt(record.get(record.size()-1)));
            System.out.println(locationStat);
            newStats.add(locationStat);
            
        }
        this.allStats = newStats;
    }


}
4

2 回答 2

1

问题可能来自这段代码

@RequestMapping("/")
public @ResponseBody String home(Model model) {
    model.addAttribute( "locationStats", covidDataService.getAllStats());
    return "home";
}

它返回应该是现有视图的“主页”，通常，该视图将是一个 jsp 文件，该文件位于 WEB-INF 中的某个位置，请参阅本教程：https ://www.baeldung.com/spring-mvc-view- resolver-tutorial 在映射错误的情况下，可能会返回 404 错误

于 2020-07-06T07:30:49.610 回答
0

当您运行服务器时，您应该能够在控制台中看到它使用了哪个端口。另外，src/main/resources/application.properties 文件中是否有 server.port=8080 ？

在控制器中，RequestMapping 注解缺少方法类型和标头

@RequestMapping(
     path="/",
     method= RequestMethod.GET,
     produces=MediaType.APPLICATION_JSON_VALUE)
        public String home(Model model) {
            model.addAttribute( "locationStats", covidDataService.getAllStats());
            return "home";
        }

确保为 POST 或 PUT 方法添加消耗

与问题有点无关，但控制器中的行缺少@Autowired 注释

CovidDataService covidDataService;

最好在构造函数中添加@Autowired

@Autowired
public HomeController(CovidDataService covidDataService) {
    this.covidDataService = covidDataService;
}
于 2020-07-05T21:13:04.727 回答