我要解组的单元素JSON数组:
[ { "id":"42", "status":"Active", "name":"purple monkey dishwasher" } ]
相应的Java类(为简便起见,省略了getters和setters方法):
@XmlRootElement @XmlAccessorType(XmlAccessType.FIELD) public class Badge { @XmlElement(name="id") private String id; @XmlElement(name="status") private Status status; @XmlElement(name="name") private String name; public static enum Status { Active, NotActive } }
发出HTTP请求的Jersey客户代码, 应该 将上述JSON解组为一个元素List<Foo>:
List<Foo>
Client client = Client.create(); WebResource apiRoot = client.resource("http://localhost:9000/api"); List<Badge> badges = apiRoot.path("/badges").get(new GenericType<List<Badge>>(){});
最后一行,特别是WebResource#get()调用,抛出以下异常:
WebResource#get()
javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"status"). Expected elements are <{}badge> at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:662) at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:258) at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:253) at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Loader.java:120) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(UnmarshallingContext.java:1063) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:498) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:480) at com.sun.xml.bind.v2.runtime.unmarshaller.InterningXmlVisitor.startElement(InterningXmlVisitor.java:75) at com.sun.xml.bind.v2.runtime.unmarshaller.StAXStreamConnector.handleStartElement(StAXStreamConnector.java:247) at com.sun.xml.bind.v2.runtime.unmarshaller.StAXStreamConnector.bridge(StAXStreamConnector.java:181) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:369) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:341) at com.sun.jersey.core.provider.jaxb.AbstractListElementProvider.readFrom(AbstractListElementProvider.java:232) at com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:552) at com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:522) at com.sun.jersey.api.client.WebResource.handle(WebResource.java:617) at com.sun.jersey.api.client.WebResource.get(WebResource.java:191) at com.redacted.badge.client.BadgerImpl.findAllBadges(BadgerImpl.java:105) at com.redacted.webapp.admin.BadgeAction.unspecified(BadgeAction.java:40) at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:245) at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170) at org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58) at org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67) at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51) at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190) at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304) at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190) at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449) at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:119) at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:55) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.redacted.webapp.filter.MemberFilter.doFilter(MemberFilter.java:83) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.redacted.webapp.filter.AuthFilter.doFilter(AuthFilter.java:113) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.displaytag.filter.ResponseOverrideFilter.doFilter(ResponseOverrideFilter.java:125) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.redacted.webapp.filter.LanguageHandlingFilter.doFilter(LanguageHandlingFilter.java:151) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.redacted.webapp.filter.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:146) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.redacted.webapp.filter.PartnerFilter.doFilter(PartnerFilter.java:59) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.redacted.webapp.filter.SessionStatusFilter.doFilter(SessionStatusFilter.java:113) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:470) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at com.googlecode.psiprobe.Tomcat60AgentValve.invoke(Tomcat60AgentValve.java:30) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:680)
我已经尝试在上使用各种注释组合Badge,或者使用数组代替GenericType:
Badge
GenericType
List<Badge> badges = Arrays.asList(apiRoot.path("/badges").get(Badge[].class));
或使用中间体ClientResponse:
ClientResponse
GenericType<List<Badge>> type = new GenericType<List<Badge>>(){}; ClientResponse clientResponse = apiRoot.path("/badges").get(ClientResponse.class); List<Badge> badges = clientResponse.getEntity(type);
但到目前为止,没有一个解决了这个问题。
更令人困惑的是,我现有的设置在解组其他结构内部的JSON编码时 没有问题Badge,如下所示:
{ "userid":"123456789", "userbadges":[ { "badge":{ "id":"42", "status":"Active", "name":"purple monkey dishwasher" }, "earned":"2012-03-06 18:16:18.172" } ] }
我究竟做错了什么?
通过使用Jersey Client实例JacksonJsonProvider的MessageBody(Reader|Writer)提供程序,我可以轻松解决此问题:
JacksonJsonProvider
MessageBody(Reader|Writer)
ClientConfig cfg = new DefaultClientConfig(); cfg.getClasses().add(JacksonJsonProvider.class); Client client = Client.create(cfg);
Jackson的MessageBodyReader实现似乎比Jersey JSON 的实现更好。
MessageBodyReader
感谢我如何自定义将JAXB对象列表序列化为JSON?把我指向杰克逊的方向。