java - RestTemplate にオブジェクトを設定できません

Question

リクエストを送信してレスポンスを受信する次のコードがあります。すべてが構成されているようですが、コードが返されていNullPointerExceptionます。

何が足りないのかわかりません。正しい URL アドレスを持つ readyURL 変数を出力しました。stackTrace はあまり提供しません。

コード

try {
    final String APIKEY = "MYAPI";
    final String URL = "http://api-sandbox.seatwave.com/v2/discovery/events?apikey="
            + APIKEY;
    String readyUrl = URL + "&what=" + name;
    RestTemplate restTemplate = new RestTemplate();
    EventsResponse eventResponse = restTemplate.getForObject(readyUrl,
            EventsResponse.class);

    System.err.println("seatwave>>>"
            + eventResponse.getEvents().getEvent().size()); //line 245
} catch (NullPointerException e) {
    e.printStackTrace();
}


@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class EventsResponse {
    @XmlElement
    private Status status;
    @XmlElement(name = "Paging")
    private Page page;
    @XmlElement
    private Events events;

    public Status getStatus() {
      return status;
    }

    public void setStatus(Status status) {
      this.status = status;
    }

    public Page getPage() {
      return page;
    }

    public void setPage(Page page) {
      this.page = page;
    }

    public Events getEvents() {
      return events;
    }

    public void setEvents(Events events) {
      this.events = events;
    }
}

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Status {
    @XmlElement(name = "Version")
    private double version;
    @XmlElement(name = "TimeStampUtc")
    private Date timeStampUtc;
    @XmlElement(name = "Code")
    private int code;
    @XmlElement(name = "Message")
    private String message;
    @XmlElement(name = "Details")
    private String details;

   public double getVersion() {
      return version;
   }

    public void setVersion(double version) {
      this.version = version;
    }

    public Date getTimeStampUtc() {
      return timeStampUtc;
    }

    public void setTimeStampUtc(Date timeStampUtc) {
      this.timeStampUtc = timeStampUtc;
    }

    public int getCode() {
     return code;
    }

  public void setCode(int code) {
     this.code = code;
  }

  public String getMessage() {
     return message;
  }

  public void setMessage(String message) {
     this.message = message;
  }

  public String getDetails() {
     return details;
  }

  public void setDetails(String details) {
     this.details = details;
  }
}

@XmlRootElement(name="Page")
@XmlAccessorType(XmlAccessType.FIELD)
public class Page {
    @XmlElement(name="PageNumber")
    private int pageNumber;
    @XmlElement(name="PageSize")
    private int pageSize;
    @XmlElement(name="PageResultCount")
    private int pageResultCount;
    @XmlElement(name="TotalResultCount")
    private int totalResultCount;
    @XmlElement(name="TotalPageCount")
    private int totalPageCount;

    public int getPageNumber() {
      return pageNumber;
    }

    public void setPageNumber(int pageNumber) {
       this.pageNumber = pageNumber;
    }

    public int getPageSize() {
      return pageSize;
   }

   public void setPageSize(int pageSize) {
      this.pageSize = pageSize;
   }

   public int getPageResultCount() {
      return pageResultCount;
   }

   public void setPageResultCount(int pageResultCount) {
      this.pageResultCount = pageResultCount;
   }

   public int getTotalResultCount() {
      return totalResultCount;
   }

   public void setTotalResultCount(int totalResultCount) {
      this.totalResultCount = totalResultCount;
   }

   public int getTotalPageCount() {
      return totalPageCount;
   }

   public void setTotalPageCount(int totalPageCount) {
     this.totalPageCount = totalPageCount;
   }

}

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Events {
    @XmlElement
    private List<Event> event;

    public List<Event> getEvent() {
      return event;
    }  

    public void setEvent(List<Event> event) {
      this.event = event;
    }
 }

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Event {
    @XmlElement(name = "Id")
    private int id;
    @XmlElement(name = "Date")
    private Date date;
    @XmlElement(name = "EventGroupName")
    private String eventGroupName;
    @XmlElement(name = "VenueName")
    private String venueName;
    @XmlElement(name = "Town")
    private String town;
    @XmlElement(name = "Country")
    private String country;
    @XmlElement(name = "TicketCount")
    private int ticketCount;
    @XmlElement(name = "Currency")
    private String currency;
    @XmlElement(name = "MinPrice")
    private double minPrice;
    @XmlElement(name = "SwURL")
    private String swUrl;
    @XmlElement(name = "EventGroupImageURL")
    private String eventGroupImageUrl;
    @XmlElement(name = "LayoutId")
    private int layoutId;
    @XmlElement(name = "EventGroupId")
    private int eventGroupId;
    @XmlElement(name = "VenueId")
    private int venueId;
    @XmlElement(name = "SwSellURL")
    private String swSellUrl;

  public int getId() {
    return id;
  }

  public void setId(int id) {
      this.id = id;
  }

  public Date getDate() {
      return date;
  }

  public void setDate(Date date) {
      this.date = date;
  }

  public String getEventGroupName() {
     return eventGroupName;
  }

  public void setEventGroupName(String eventGroupName) {
        this.eventGroupName = eventGroupName;
  }

  public String getVenueName() {
      return venueName;
  }

  public void setVenueName(String venueName) {
      this.venueName = venueName;
  }

  public String getTown() {
     return town;
  }

  public void setTown(String town) {
     this.town = town;
  }

  public String getCountry() {
     return country;
  }

  public void setCountry(String country) {
        this.country = country;
  }

  public int getTicketCount() {
        return ticketCount;
  }

  public void setTicketCount(int ticketCount) {
        this.ticketCount = ticketCount;
  }

  public String getCurrency() {
        return currency;
  }

  public void setCurrency(String currency) {
        this.currency = currency;
  }

  public double getMinPrice() {
        return minPrice;
  }

  public void setMinPrice(double minPrice) {
        this.minPrice = minPrice;
  }

  public String getSwUrl() {
        return swUrl;
  }

  public void setSwUrl(String swUrl) {
        this.swUrl = swUrl;
  }

  public String getEventGroupImageUrl() {
        return eventGroupImageUrl;
  }

  public void setEventGroupImageUrl(String eventGroupImageUrl) {
        this.eventGroupImageUrl = eventGroupImageUrl;
  }

  public int getLayoutId() {
        return layoutId;
  }

  public void setLayoutId(int layoutId) {
        this.layoutId = layoutId;
  }

  public int getEventGroupId() {
        return eventGroupId;
  }

  public void setEventGroupId(int eventGroupId) {
        this.eventGroupId = eventGroupId;
  }

  public int getVenueId() {
        return venueId;
  }

  public void setVenueId(int venueId) {
        this.venueId = venueId;
  }

  public String getSwSellUrl() {
        return swSellUrl;
  }

  public void setSwSellUrl(String swSellUrl) {
        this.swSellUrl = swSellUrl;
  }
}

例外

java.lang.NullPointerException
    at com.myproject.tickets.service.TicketSeviceImpl.seatWave(TicketSeviceImpl.java:245)
    at com.myproject.tickets.service.TicketSeviceImpl.findTicket(TicketSeviceImpl.java:45)
    at com.myproject.web.TicketController.findTicket(TicketController.java:29)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:369)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:112)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:177)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:168)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)

サンプル結果

<?xml version="1.0" encoding="UTF-8"?>
<EventsResponse xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
   <Status>
      <Version>2.0</Version>
      <TimeStampUtc>2015-09-27T08:44:24</TimeStampUtc>
      <Code>0</Code>
      <Message>Success</Message>
      <Details />
   </Status>
   <Paging>
      <PageNumber>1</PageNumber>
      <PageSize>50</PageSize>
      <PageResultCount>50</PageResultCount>
      <TotalResultCount>7889</TotalResultCount>
      <TotalPageCount>158</TotalPageCount>
   </Paging>
   <Events>
      <Event>
         <Id>948040</Id>
         <Date>2015-09-27T14:30:00</Date>
         <EventGroupName>The Lion King - London</EventGroupName>
         <VenueName>Lyceum Theatre London</VenueName>
         <Town>London</Town>
         <Country>UK</Country>
         <TicketCount>183</TicketCount>
         <Currency>GBP</Currency>
         <MinPrice>29.75</MinPrice>
         <SwURL>http://www.seatwave.com/the-lion-king-london-tickets/lyceum-theatre--tickets/27-september-2015/perf/948040?affid=&amp;appid=203710</SwURL>
         <EventGroupImageURL>http://z.stwv.im/filestore/season/image/the-lion-king_000277_1_mainpicture.jpg</EventGroupImageURL>
         <LayoutId>232</LayoutId>
         <EventGroupId>277</EventGroupId>
         <VenueId>232</VenueId>
         <SwSellURL>http://www.seatwave.com/sellticketdetails?performanceId=948040&amp;affid=&amp;appid=2037810</SwSellURL>
      </Event>
      <Event>
         <Id>987509</Id>
         <Date>2015-09-27T15:00:00</Date>
         <EventGroupName>American Idiot</EventGroupName>
         <VenueName>Arts Theatre London</VenueName>
         <Town>London</Town>
         <Country>UK</Country>
         <TicketCount>28</TicketCount>
         <Currency>GBP</Currency>
         <MinPrice>35.7</MinPrice>
         <SwURL>http://www.seatwave.com/american-idiot-tickets/arts-theatre-tickets/27-september-2015/perf/987509?affid=&amp;appid=2037810</SwURL>
         <EventGroupImageURL>http://z.stwv.im/filestore/season/image/americanidiot_32152_1_1_20111209091615.jpg</EventGroupImageURL>
         <LayoutId>4576</LayoutId>
         <EventGroupId>32152</EventGroupId>
         <VenueId>4207</VenueId>
         <SwSellURL>http://www.seatwave.com/sellticketdetails?performanceId=987509&amp;affid=&amp;appid=2037810</SwSellURL>
      </Event>
      <Event>
         <Id>948273</Id>
         <Date>2015-09-27T15:00:00</Date>
         <EventGroupName>Matilda The Musical</EventGroupName>
         <VenueName>Cambridge Theatre</VenueName>

アップデート

このコードを restTemplate.getForObject 行の直後に追加しましたが、コンソールには何も表示されません。

if(eventResponse == null)
            {
                System.err.println("it is null");
            }else{

            System.err.println("message:>>"+eventResponse.getStatus().getMessage());
            }

score 1 · Accepted Answer

Spring の RestTemplate をSeatWave の APIで動作させることができました

以下は github での実例です: https://github.com/cosbor11/seatwave-spring-client-example

手順は次のとおりです。

次の GET URL をブラウザに入力します。

http://api-sandbox.seatwave.com/v2/discovery/events?apikey=4739E4694D0E482A92C9D0B478D83934&what=music
ソースを表示し、xml をコピーしてxsd ジェネレーターに貼り付けます。
選択した xsd を生成しRussian Doll Styleます。
生成されたコンテンツを、次のような場所にある新しいファイルに貼り付けます${home}/Desktop/schema.xsd。
次のようになっている場合は、最初の行を削除します。<?xml version="1.0" encoding="utf-16"?>

次のような binding.xmlファイルを作成します。

<jaxb:bindings xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:jaxb="http://java.sun.com/xml/ns/jaxb" version="2.1">
    <jaxb:globalBindings localScoping="toplevel"/>
</jaxb:bindings>

src ファイルを作成します: mkdir src.
次のように XJC を使用して、Java Jaxb クラスをそのフォルダーに生成します。

xjc -b ~/Desktop/binding.xml -d src -p com.yourcompany ~/Desktop/schema.xsd
生成されたクラスとパッケージ構造をビルドパスにコピーしてください。

また、ビルドパスで、mainRestTemplate を使用するメソッドでクラスを作成します。

public static void main(String args[])
{
    try
    {

        String name = "music";
        final String APIKEY = "4739E4694D0E482A92C9D0B478D83934"; //http://api-sandbox.seatwave.com/v2/discovery/events?apikey=4739E4694D0E482A92C9D0B478D83934&what=music
        final String URL = "http://api-sandbox.seatwave.com/v2/discovery/events?apikey=" + APIKEY;
        String readyUrl = URL + "&what=" + name;
        RestTemplate restTemplate = new RestTemplate();
        EventsResponse eventResponse = restTemplate.getForObject(readyUrl, EventsResponse.class);

        System.err.println("seatwave>>>" + eventResponse.getEvents().getEvent().size());
    }
    catch (NullPointerException e)
    {
        e.printStackTrace();
    }
}

そのクラスをコンパイルし、mainメソッドを実行します。この例では、サイズとして 50 レコードを取得する必要があります。name変数を空のセットを返すものに変更しても、 NullPointerExeption.

生成された JAXB クラスは次のようになります。

EventResponse.java:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
    "status",
    "paging",
    "events"
})
@XmlRootElement(name = "EventsResponse")
public class EventsResponse {

    @XmlElement(name = "Status", required = true)
    protected Status status;
    @XmlElement(name = "Paging", required = true)
    protected Paging paging;
    @XmlElement(name = "Events", required = true)
    protected Events events;

    //getters & setters

Events.java:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
    "event"
})
public class Events {

    @XmlElement(name = "Event", required = true)
    protected List<Event> event;

    public List<Event> getEvent() {
        if (event == null) {
            event = new ArrayList<Event>();
        }
        return this.event;
    }

}

イベント.java:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
    "id",
    "date",
    "eventGroupName",
    "venueName",
    "town",
    "country",
    "ticketCount",
    "currency",
    "minPrice",
    "swURL",
    "eventGroupImageURL",
    "layoutId",
    "eventGroupId",
    "venueId",
    "swSellURL"
})
public class Event {

    @XmlElement(name = "Id")
    protected int id;
    @XmlElement(name = "Date", required = true)
    @XmlSchemaType(name = "dateTime")
    protected XMLGregorianCalendar date;
    @XmlElement(name = "EventGroupName", required = true)
    protected String eventGroupName;
    @XmlElement(name = "VenueName", required = true)
    protected String venueName;
    @XmlElement(name = "Town", required = true)
    protected String town;
    @XmlElement(name = "Country", required = true)
    protected String country;
    @XmlElement(name = "TicketCount")
    protected int ticketCount;
    @XmlElement(name = "Currency", required = true)
    protected String currency;
    @XmlElement(name = "MinPrice", required = true)
    protected BigDecimal minPrice;
    @XmlElement(name = "SwURL", required = true)
    protected String swURL;
    @XmlElement(name = "EventGroupImageURL", required = true)
    protected String eventGroupImageURL;
    @XmlElement(name = "LayoutId")
    protected int layoutId;
    @XmlElement(name = "EventGroupId")
    protected int eventGroupId;
    @XmlElement(name = "VenueId")
    protected int venueId;
    @XmlElement(name = "SwSellURL", required = true)
    protected String swSellURL;

    //getter & setters

ノート：

Maven を使用している場合は、jaxb クラスをgenerated-sourcesフォルダーに自動的に生成する便利なツールがいくつかあります。cxf-xjc-pluginをお勧めします。

Events#getEvent()イベントプロパティが null の場合、メソッドは新しい List を返すことに注意してください。

binding.xml ファイルは、jaxb の生成方法をカスタマイズするのに便利です。いじってみると、より直感的な方法で API クラスを操作する方法を理解できるはずです。たとえば、メインクラスでは、eventResponse.getEvents().size()代わりにを呼び出すことでサイズを取得できますeventResponse.getEvents().getEvent().size()。

score 0 · Accepted Answer

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class EventsResponse {

    @XmlElementWrapper
    @XmlElement(name="event")
    private List<Event> events;

}

Events クラスは削除できます。

java - RestTemplate にオブジェクトを設定できません

3 に答える 3

Spring の RestTemplate をSeatWave の APIで動作させることができました

手順は次のとおりです。

生成された JAXB クラスは次のようになります。

Related

Reference