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java - RestTemplate 无法填充对象

转载 作者:塔克拉玛干 更新时间:2023-11-03 05:32:04 25 4
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我有以下代码来发送请求和接收响应,似乎一切都已配置但代码正在返回 NullPointerException

我不确定缺少什么。我打印出具有正确 URL 地址的 readyURL 变量。 stackTrace 提供的不多。

代码

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;
}
}

异常

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)

示例结果

<?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>

更新

我在 restTemplate.getForObject 行之后添加了这段代码,但控制台上不会显示任何内容。

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

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

最佳答案

我通过一些映射更改使您的代码正常工作:

@XmlRootElement(name = "EventsResponse") // added (name = "EventsResponse")
@XmlAccessorType(XmlAccessType.FIELD)
public class EventsResponse {
@XmlElement(name = "Status")
private Status status;
@XmlElement(name = "Paging")
private Page page;
@XmlElementWrapper(name="Events") // added
@XmlElement(name = "Event") // added (name = "Event")
private List<Event> events;

// getters, setter
}

@XmlRootElement // removed name =
@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;

// getters, setter
}

@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;

// getters, setter
}

@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;

// getters, setter
}

然后我使用 Wiremock 测试了它:

package so32806530;

import com.github.tomakehurst.wiremock.WireMockServer;
import com.github.tomakehurst.wiremock.core.WireMockConfiguration;
import org.springframework.web.client.RestTemplate;

import static com.github.tomakehurst.wiremock.client.WireMock.*;

public class App {

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

public static void main(final String[] args) {
// ---------- starts fake API server -----
final WireMockServer wireMockServer = new WireMockServer(WireMockConfiguration.wireMockConfig().port(8089));
wireMockServer.stubFor(get(urlMatching("/v2/discovery/events.*")).willReturn(aResponse().withHeader("Content-type", "application/xml").withStatus(200).withBody(XML)));
wireMockServer.start();
// ---------------------------------------

try {
final String name = "foo";
final String APIKEY = "MYAPI";
final String URL = "http://localhost:8089/v2/discovery/events?apikey=" + APIKEY;
final String readyUrl = URL + "&what=" + name;
final RestTemplate restTemplate = new RestTemplate();
final EventsResponse eventResponse = restTemplate.getForObject(readyUrl, EventsResponse.class);

System.err.println("seatwave>>>" + eventResponse.getEvents().size());

for (final Event event : eventResponse.getEvents()) {
System.out.println("EventID: " + event.getId());
}
} catch (final Exception ex) {
ex.printStackTrace();
}

// ---------- stops fake API server ------
wireMockServer.stop();
// ---------------------------------------
}
}

输出:

seatwave>>>2
EventID: 948040
EventID: 987509

一些关于 JAXB 和集合的阅读:http://blog.bdoughan.com/2010/09/jaxb-collection-properties.html (注意:不是我的博客)


使用的版本:

  • spring-web: 4.0.5.RELEASE
  • jaxb-api: 2.2.1
  • 线模:1.57

关于java - RestTemplate 无法填充对象,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32806530/

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