问题描述
我从rest api获取json,我想将数据存储在POJO列表中。下面是相同的代码:
public List<myObject> mapper(){
String myObjectData= restClient.getAllOriginal("myObject");
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false);
objectMapper.configure(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY,true);
CollectionType typeReference =
TypeFactory.defaultInstance().constructCollectionType(List.class,myObject.class);
List<CommitmentPojo> resultDto = null;
try
{
resultDto = objectMapper.readValue(myObjectData,typeReference);
}
catch (JsonParseException e)
{
e.printStackTrace();
}
catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return resultDto;
}
我添加了FAIL_ON_UNKNOWN_PROPERTIES
配置,因为与POJO相比,我在json中增加了额外的列,并且无法更改POJO(除非直到需要),因为我必须更改更多内容。我在下面的行中遇到异常时为对象映射器添加了ACCEPT_SINGLE_VALUE_AS_ARRAY
配置:(我怀疑这是现在引起问题的原因)
// [JACKSON-526]: implicit arrays from single values?
if (!ctxt.isEnabled(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)) {
throw ctxt.mappingException(_collectionType.getRawClass());
}
这来自CollectionDeserializer.handleNonArray方法。
从rest api获取字符串的方法:
public String getAllOriginal(String resourcePath) {
// Objects.requireNonNull(this.baseUri,"target cannot be null");
return this.client
.target("http://comtsrvc.ny.qa.flx.nimbus.gs.com:3802/v2/")
.path(resourcePath)
.request(MediaType.APPLICATION_JSON_TYPE)
.cookie("GSSSO",getCookie())
.get()
.readEntity(String.class);
}
下面是我的json:
{
"myObject" : [ {
"key" : {
"srcSys" : "REPO_1","srcSysRef" : "20200909_1911_1"
},"productData" : {
"id" : null,"number" : null,"isn" : null,"productId" : null,"productAdditionalData" : {
"assetClassTree" : "UNCLASSIFIED","description" : "UNCLASSIFIED","productTypeData" : {
"productType" : "UNCLASSIFIED","productGroup" : "UNCLASSIFIED"
}
}
},"state" : "OPEN","type" : "01"
},{
"key" : {
"srcSys" : "REPO_2","srcSysRef" : "20200403_3892_1"
},"productData" : {
"id" : "1","number" : "11","isn" : "null","productId" : 1234,"productAdditionalData" : {
"assetClassTree" : "xyz","description" : "abc","tradAcctType" : "01"
} ]
}
问题是:所有值都为null,列表的大小为1。能否告诉我我的代码有什么问题?
解决方法
尝试将其反序列化为Map
:
import com.fasterxml.jackson.core.type.TypeReference;
...
Map<String,List<MyObject>> root = mapper.readValue(jsonFile,new TypeReference<Map<String,List<MyObject>>>() {});
List<MyObject> objects = root.get("myObject");
因此,您无需为根级别创建新的POJO
。 Map
也可以使用。