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问题：

Empty（null）GET使用imDb API

濮献
2023-03-14

我遇到了无法获取任何内容的问题，现在我获取了一些内容，但它是完全空的（null）。还有一件事，如果用GET解决了这个问题，我如何用HTML管理这个页面，比如很好地显示文本等等。？

代码如下：

类Appcontroller：

@RestController //Das hier ist ein RestController
@RequestMapping (method = RequestMethod.GET, produces = { "application/json; charset=utf-8" })
@JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)


public class AppController {

    @Autowired
    private RestTemplate restTemplate;

    private static String url = "https://imdb-api.com/en/API/Top250Movies/k_1kz039kt";
    
    @GetMapping("/top250movies")
    public List<Response> getTop250Movies(){
        final Response top250movies= restTemplate.getForObject(url, Response.class);
    return Arrays.asList(top250movies);
    }
}

Class Main应用程序：

@SpringBootApplication

public class MainApplication {

    @Bean
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }

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

班级响应：

package ch.emin.m226;

import java.util.List;

import org.springframework.ui.Model;

public class Response {

    private List<Object> items;
    
    public String rank;
    public String title;
    public String fullTitle;
    public String year;
    public String image;
    public String crew;
    public String imDbRating;
    public String imDbRatingCount;

    public Response(){
        
    }

    public Response(String rank, String title, String fullTitle, String year, String image, String crew, String imDbRating, String imDbRatingCount) {
        this.rank = rank;
        this.title = title;
        this.fullTitle = fullTitle;
        this.year = year;
        this.image = image;
        this.crew = crew;
        this.imDbRating = imDbRating;
        this.imDbRatingCount = imDbRatingCount;

    }
    public String getRank() {
        return rank;
    }
    public void setRank(String rank) {
        this.rank = rank;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getFullTitle() {
        return fullTitle;
    }
    public void setFullTitle(String fullTitle) {
        this.fullTitle = fullTitle;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getImage() {
        return image;
    }
    public void setImage(String image) {
        this.image = image;
    }
    public String getCrew() {
        return crew;
    }
    public void setCrew(String crew) {
        this.crew = crew;
    }
    public String imDbRating() {
        return imDbRating;
    }
    public void imDbRating(String imDbRating) {
        this.imDbRating = imDbRating;
    }
    public String imDbRatingCount() {
        return imDbRatingCount;
    }
    public void imDbRatingCount(String imDbRatingCount) {
        this.imDbRatingCount = imDbRatingCount;
    }
    

    
}

这就是我在浏览器上得到的：

[
  {
    "rank": null,
    "title": null,
    "fullTitle": null,
    "year": null,
    "image": null,
    "crew": null,
    "imDbRating": null,
    "imDbRatingCount": null
  }
]

提供修复后：

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.
Sat Jun 11 17:14:37 CEST 2022
There was an unexpected error (type=Internal Server Error, status=500).
Type definition error: [simple type, class ch.emin.m226.ResponseWrapper]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class ch.emin.m226.ResponseWrapper and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: java.util.Arrays$ArrayList[0])
org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class ch.emin.m226.ResponseWrapper]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class ch.emin.m226.ResponseWrapper and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: java.util.Arrays$ArrayList[0])
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:462)
    at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:104)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:290)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:183)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:78)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:135)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class ch.emin.m226.ResponseWrapper and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: java.util.Arrays$ArrayList[0])
    at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:77)
    at com.fasterxml.jackson.databind.SerializerProvider.reportBadDefinition(SerializerProvider.java:1300)
    at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:400)
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:46)
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:29)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:145)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:107)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:25)
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480)
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:400)
    at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1514)
    at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:1007)
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:456)
    ... 48 more

新代码：

类AppController：

@RestController //Das hier ist ein RestController
@RequestMapping (method = RequestMethod.GET, produces = { "application/json; charset=utf-8" })
@JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)


public class AppController {

    @Autowired
    private RestTemplate restTemplate;

    private static String url = "https://imdb-api.com/en/API/Top250Movies/k_1kz039kt";
    
    @GetMapping("/top250movies")
    public List<ResponseWrapper> getTop250Movies(){
        final ResponseWrapper top250movies= restTemplate.getForObject(url, ResponseWrapper.class);
    return Arrays.asList(top250movies);
    }
}

Class Main应用程序：

@RestController //Das hier ist ein RestController
@RequestMapping (method = RequestMethod.GET, produces = { "application/json; charset=utf-8" })
@JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)


public class AppController {

    @Autowired
    private RestTemplate restTemplate;

    private static String url = "https://imdb-api.com/en/API/Top250Movies/k_1kz039kt";
    
    @GetMapping("/top250movies")
    public List<ResponseWrapper> getTop250Movies(){
        final ResponseWrapper top250movies= restTemplate.getForObject(url, ResponseWrapper.class);
    return Arrays.asList(top250movies);
    }
}

班级响应：

public class Response {

    //private List<Object> items; No need of this since the item should be of //response scema
    
    public String rank;
    public String title;
    public String fullTitle;
    public String year;
    public String image;
    public String crew;
    public String imDbRating;
    public String imDbRatingCount;

    public Response(){
        
    }

    public Response(String rank, String title, String fullTitle, String year, String image, String crew, String imDbRating, String imDbRatingCount) {
        this.rank = rank;
        this.title = title;
        this.fullTitle = fullTitle;
        this.year = year;
        this.image = image;
        this.crew = crew;
        this.imDbRating = imDbRating;
        this.imDbRatingCount = imDbRatingCount;

    }
    public String getRank() {
        return rank;
    }
    public void setRank(String rank) {
        this.rank = rank;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getFullTitle() {
        return fullTitle;
    }
    public void setFullTitle(String fullTitle) {
        this.fullTitle = fullTitle;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getImage() {
        return image;
    }
    public void setImage(String image) {
        this.image = image;
    }
    public String getCrew() {
        return crew;
    }
    public void setCrew(String crew) {
        this.crew = crew;
    }
    public String imDbRating() {
        return imDbRating;
    }
    public void imDbRating(String imDbRating) {
        this.imDbRating = imDbRating;
    }
    public String imDbRatingCount() {
        return imDbRatingCount;
    }
    public void imDbRatingCount(String imDbRatingCount) {
        this.imDbRatingCount = imDbRatingCount;
    }
    

    
}

类响应包装器：

import java.util.List;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

@Getter
@Setter
@Builder
@AllArgsConstructor
@NoArgsConstructor //Lombok annotations
class ResponseWrapper{
  private List<Response> items;
}

共有1个答案

锺离霖
2023-03-14

imdb提供的响应模式是一个json对象，其中包含将映射到每个电影的详细信息的项目列表。

一种方法-

另一种方式-

final ResponseWrapper top250movies= restTemplate.getForObject(url, ResponseWrapper.class);

@Getter
@Setter
@Builder //Lombok annotations
class ResponseWrapper{
  private List<Response> items;
}

// Or try just basic getters and setters without any lombok annotation.

package ch.emin.m226;

import java.util.List;

import org.springframework.ui.Model;

public class Response {

    //private List<Object> items; No need of this since the item should be of //response scema
    
    public String rank;
    public String title;
    public String fullTitle;
    public String year;
    public String image;
    public String crew;
    public String imDbRating;
    public String imDbRatingCount;

    public Response(){
        
    }

    public Response(String rank, String title, String fullTitle, String year, String image, String crew, String imDbRating, String imDbRatingCount) {
        this.rank = rank;
        this.title = title;
        this.fullTitle = fullTitle;
        this.year = year;
        this.image = image;
        this.crew = crew;
        this.imDbRating = imDbRating;
        this.imDbRatingCount = imDbRatingCount;

    }
    public String getRank() {
        return rank;
    }
    public void setRank(String rank) {
        this.rank = rank;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getFullTitle() {
        return fullTitle;
    }
    public void setFullTitle(String fullTitle) {
        this.fullTitle = fullTitle;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getImage() {
        return image;
    }
    public void setImage(String image) {
        this.image = image;
    }
    public String getCrew() {
        return crew;
    }
    public void setCrew(String crew) {
        this.crew = crew;
    }
    public String imDbRating() {
        return imDbRating;
    }
    public void imDbRating(String imDbRating) {
        this.imDbRating = imDbRating;
    }
    public String imDbRatingCount() {
        return imDbRatingCount;
    }
    public void imDbRatingCount(String imDbRatingCount) {
        this.imDbRatingCount = imDbRatingCount;
    }
    

    
}
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