无法从START_OBJECT标记中反序列化java.util.ArrayList的实例 [英] Can not deserialize instance of java.util.ArrayList out of START_OBJECT token
问题描述
我正在尝试发布自定义对象的列表
。
请求正文中的我的JSON是这样的:
I'm trying to POST a List
of custom objects.
My JSON in request body is this:
{
"collection": [
{
"name": "Test order1",
"detail": "ahk ks"
},
{
"name": "Test order2",
"detail": "Fisteku"
}
]
}
处理请求的服务器端代码:
Server side code that handles the request:
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() + "]";
}
}
但抛出异常:
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)
推荐答案
问题是JSON - 默认情况下,这不能被反序列化为集合
,因为它实际上不是JSON数组 - 看起来像这样:
The problem is the JSON - this cannot, by default, be deserialized into a Collection
because it's not actually a JSON Array - that would look like this:
[
{
"name": "Test order1",
"detail": "ahk ks"
},
{
"name": "Test order2",
"detail": "Fisteku"
}
]
因为你没有控制反序列化的确切过程(RestEasy会这样做) - 第一个选项会是简单地将JSON注入 String
,然后控制反序列化过程:
Since you're not controlling the exact process of deserialization (RestEasy does) - a first option would be to simply inject the JSON as a String
and then take control of the deserialization process:
Collection<COrder> readValues = new ObjectMapper().readValue(jsonAsString, new TypeReference<Collection<COrder>>() { });
你可以放松一些不必自己做的便利,但是你很容易排序出问题。
You would loose a bit of the convenience of not having to do that yourself, but you would easily sort out the problem.
另一个选项 - 如果你不能改变JSON - 将构造一个包装器以适应你的JSON输入的结构 - 并使用它而不是 Collection< COrder>
。
Another option - if you cannot change the JSON - would be to construct a wrapper to fit the structure of your JSON input - and use that instead of Collection<COrder>
.
希望这会有所帮助。
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