当使用以下JSON并且“phones”或“emailAddresses”为空时,我得到了NullPointerException。
JSON:
{
"item": {
"messages": {
"user.phone.missing": {
"type": "warning",
"key": "user.phone.missing",
"message": "User profile does not have a phone number",
"code": null
},
"user.email.missing": {
"type": "warning",
"key": "user.email.missing",
"message": "User profile does not have an email address",
"code": null
},
"user.es.sync.failed": {
"type": "error",
"key": "user.es.sync.failed",
"message": "Unable to sync user",
"code": null
}
},
"user": {
"firstName": "Test",
"middleInitial": null,
"lastName": "User",
"createdDt": "2016-04-20 19:50:03+0000",
"updatedDt": null,
"lastVerifiedDt": null,
"status": "DEACTIVATED",
"tokens": [
{
"tokenHash": "test hash",
"tokenValue": "test dn",
"createdDt": "2016-04-20 19:50:03+0000",
"updatedDt": null,
"status": "ENABLED"
}
],
"phones": null,
"emailAddresses": null
}
},
"status": "SUCCESS",
"errors": []
}
这是堆栈跟踪:
Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: N/A (through reference chain: com.test.message.cte.CteItemResponse["item"]->com.test.message.cte.CteUserContext["user"]->com.test.User["phones"])
at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:510)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:493)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.set(MethodProperty.java:116)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:98)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:295)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:464)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:98)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:295)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:464)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:98)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:295)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2888)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2041)
at com.test.Test.main(Test.java:20)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.NullPointerException
at com.test.User.setPhones(User.java:202)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.set(MethodProperty.java:114)
... 19 more
我正在这样设置我的自定义ObjectMapper:
package com.test;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.util.ISO8601DateFormat;
public class MigrationObjectMapper extends ObjectMapper {
private MigrationObjectMapper() {
// do not serialize null value fields
this.setSerializationInclusion(JsonInclude.Include.NON_NULL);
configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
}
public static MigrationObjectMapper getMigrationObjectMapper(){
return new MigrationObjectMapper();
}
}
这意味着
CteUserContext cteUserContext = MigrationObjectMapper.getMigrationObjectMapper().convertValue(item.getItem(), new TypeReference<CteUserContext>(){});
引发错误。在CteUserContext内部是一个User对象,其中包含List和List。难道不应该不只是基于对象映射器配置来序列化这些对象吗?
最佳答案
Per Rocki的评论:
setSerializationInclusion将只忽略null值
序列化而不是反序列化。
我没有处理User类中传入的“phones”值是否为空,因此抛出了NPE。我已更新以确认它不为空。如果是这样,它将在任何其他逻辑之前短路:
/**
* @param phones The phones
*/
@JsonProperty("phones")
public void setPhones(List<Phone> phones) {
if ((phones != null) && (phones.size() > 1)) {
int primaryIndex = -1;
Phone primaryPhone = null;
for (Phone p : phones) {
if (p.getIsPrimary()) {
primaryIndex = phones.indexOf(p);
primaryPhone = p;
break;
}
}
phones.remove(primaryIndex);
phones.add(0, primaryPhone);
}
this.phones = phones;
}