无法反序列化START_OBJECT令牌之外的java.util.ArrayList实例
无法反序列化START_OBJECT令牌之外的java.util.ArrayList实例
提问于 2013-12-30 18:39:54
我正在尝试发布一个自定义对象的List。我的请求正文中的JSON是：
{
"collection": [
{
"name": "Test order1",
"detail": "ahk ks"
},
{
"name": "Test order2",
"detail": "Fisteku"
}
]
}处理请求的服务器端代码：
import java.util.Collection;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
@Path(value = "/rest/corder")
public class COrderRestService {
@POST
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public Response postOrder(Collection<COrder> orders) {
StringBuilder stringBuilder = new StringBuilder();
for (COrder c : orders) {
stringBuilder.append(c.toString());
}
System.out.println(stringBuilder);
return Response.ok(stringBuilder, MediaType.APPLICATION_JSON).build();
}
}实体COrder
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class COrder {
String name;
String detail;
@Override
public String toString() {
return "COrder [name=" + name + ", detail=" + detail
+ ", getClass()=" + getClass() + ", hashCode()=" + hashCode()
+ ", toString()=" + super.toString() + "]";
}
}但是抛出了一个异常：
SEVERE: Failed executing POST /rest/corder
org.jboss.resteasy.spi.ReaderException: org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token
at [Source: org.apache.catalina.connector.CoyoteInputStream@6de8c535; line: 1, column: 1]
at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:183)
at org.jboss.resteasy.core.MethodInjectorImpl.injectArguments(MethodInjectorImpl.java:88)
at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:111)
at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:280)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:234)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:221)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:356)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:179)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:220)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
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.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
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:100)
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:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$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:724)回答 10
Stack Overflow用户
发布于 2018-05-02 21:12:10
您可以像下面这样更新ObjectMapper对象，而不是JSON文档：
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);Stack Overflow用户
发布于 2019-04-12 01:22:05
与Eugen的回答相关，您可以通过创建一个包含Collection<COrder>作为其成员变量的wrapper POJO对象来解决这种特殊情况。这将正确地指导Jackson将实际的Collection数据放在POJO的成员变量中，并生成您在API请求中查找的JSON。
示例：
public class ApiRequest {
@JsonProperty("collection")
private Collection<COrder> collection;
// getters
}然后将COrderRestService.postOrder()的参数类型设置为新的ApiRequest包装器POJO，而不是Collection<COrder>。
Stack Overflow用户
发布于 2020-05-06 17:45:35
如上所述，以下方法可以解决这个问题：mapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
然而，在我的例子中，提供者将这个0..1或0..*序列化更像是一个bug，我不能强制修复。另一方面，它不想影响我的严格映射器用于所有其他需要严格验证的情况。
所以我做了一个杰克逊讨厌的黑客攻击(一般不应该复制;-) )，特别是因为我的SingleOrListElement只有几个属性需要修补：
@JsonProperty(value = "SingleOrListElement", access = JsonProperty.Access.WRITE_ONLY)
private Object singleOrListElement;
public List<SingleOrListElement> patch(Object singleOrListElement) {
if (singleOrListElement instanceof List) {
return (ArrayList<SingleOrListElement>) singleOrListElement;
} else {
LinkedHashMap map = (LinkedHashMap) singleOrListElement;
return Collections.singletonList(SingletonList.builder()
.property1((String) map.get("p1"))
.property2((Integer) map.get("p2"))
.build());
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/20837856
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