how to unmarshall JSON Array to array of classes
Question
I have JSON array I need to get in to either a List or Array of Classes. I tried, not much info on it, the Camel DataFormats UseList=true, but, I don't think I have a handle on what to expect from UseList on DataFormats.
<dataFormats>
<!-- include="NOT_NULL" -->
<json id="Json2Pojo" library="Jackson" prettyPrint="true" unmarshalTypeName="com.ga.dig.fleet.entities.TokenEntities"/>
<json disableFeatures="FAIL_ON_UNKNOWN_PROPERTIES"
id="AssetEntitiesPojo" library="Jackson"
prettyPrint="true"
unmarshalTypeName="com.ga.dig.fleet.entities.AssetEntities" useList="true"/>
<json disableFeatures="FAIL_ON_UNKNOWN_PROPERTIES"
id="TagEntitiesPojo" library="Jackson"
prettyPrint="true"
unmarshalTypeName="com.ga.dig.fleet.entities.TagEntities" useList="true"/>
</dataFormats>
The inbound JSON looks like, show only one block - can be long
[
{
"tagDisplayMode": "Default",
"maxHistoryQueueSize": 0,
"pollCycleInMilliseconds": 600000,
"doRecordObservationIfModeNotMet": true,
"timeZoneId": "Eastern Standard Time",
"isActive": true,
"isProduction": false,
"isLocked": false,
"lockCreatedTime": null,
"lockedByUserId": null,
"lockedByUsername": null,
"copiedFromAssetGuid": "da3909da-6296-463d-8c01-41694a51ac61",
"connectionGuid": "c7d25ac9-9e71-4ba5-938b-71ccef762373",
"customMaxHistoryQueueSize": false,
"customPollCycleInterval": false,
"blueprintGuid": "be1e2d8e-0b88-4a23-aa66-c6abe59b0d50",
"source_TZ": 32,
"source_DST": false,
"asset_TZ": 32,
"asset_DST": false,
"displayName": "BC101_Compressor",
"description": "",
"note": "",
"calculatedVariablesValid": false,
"calculatedVariablesHasLatestData": false,
"customTimeZone": true,
"lineage": "Rendered in procs only",
"connectionDisplayName": "BP Cooper River BC101",
"assetBlueprintDisplayName": "CHM_CENTRIFUGAL_COMPRESSOR_5STG_S",
"modes": null,
"assetTags": null,
"collectionType": "SampleAndHold",
"blueprintVersion": "1.0.0",
"deploymentNote": null,
"parentGuid": "e0ad48b5-0c4c-4efc-ba42-53771c416aaa",
"createdDate": "2019-05-07T21:32:05.1323509Z",
"createdBy": "7a4cb4d4-8b54-4a8e-977e-f38d4c6f73bb",
"itemGuid": "50480a32-cd65-4b93-94f8-4ba50cf6dec5",
"isDeleted": false,
"ordinalPosition": 19,
"itemCategory": "InstanceEntity",
"lastChangedDate": "2019-05-07T22:33:32.1101895Z",
"lastChangedBy": "7a4cb4d4-8b54-4a8e-977e-f38d4c6f73bb",
"links": [
{
"rel": "self",
"href": "https://apm-sm-analytic-svc-prod.app-api.aws-usw02-pr.p.io/api/v1/assets/50480a32-cd65-4b93-94f8-4ba50cf6dec5"
},
{
"rel": "blueprint",
"href": "https://apm-sm-blueprint-svc-prod.app-api.aws-usw02-pr.p.io/api/v0/blueprints/be1e2d8e-0b88-4a23-aa66-c6abe59b0d50?version=1.0.0"
},
{
"rel": "modeltagrules",
"href": "https://apm-sm-blueprint-svc-prod.app-api.aws-usw02-pr.p.io/api/v0/blueprints/be1e2d8e-0b88-4a23-aa66-c6abe59b0d50/modeltagrules?version=1.0.0"
},
{
"rel": "assettagrules",
"href": "https://apm-sm-blueprint-svc-prod.app-api.aws-usw02-pr.p.io/api/v0/blueprints/be1e2d8e-0b88-4a23-aa66-c6abe59b0d50/assettagrules?version=1.0.0"
},
{
"rel": "modes",
"href": "https://apm-sm-analytic-svc-prod.app-api.aws-usw02-pr.p.io/api/v1/assets/50480a32-cd65-4b93-94f8-4ba50cf6dec5/modes"
},
{
"rel": "tags",
"href": "https://apm-sm-analytic-svc-prod.app-api.aws-usw02-pr.p.io/api/v1/assets/50480a32-cd65-4b93-94f8-4ba50cf6dec5/tags"
},
{
"rel": "trainingdata",
"href": "https://apm-sm-analytic-svc-prod.app-api.aws-usw02-pr.p.io/api/v1/assets/50480a32-cd65-4b93-94f8-4ba50cf6dec5/trainingdata"
},
{
"rel": "historicdatablobkey",
"href": "https://apm-sm-analytic-svc-prod.app-api.aws-usw02-pr.p.io/api/v1/assets/50480a32-cd65-4b93-94f8-4ba50cf6dec5/historicdatablobkey"
}
]
},
{
... on and on... fortunately I am only concerned with a few of these elements. isActive, displayName, and itemGuid
My JSON mapper class
import java.util.HashMap;
import java.util.Map;
//JSON READ ANNOTATIONS affect how Jackson parses JSON into POJO's
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonSetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
//@JsonIgnoreProperties({ "token_type", "scope", "jti" })
public class AssetEntities {
private static final long serialVersionUID = 201903211122L;
@JsonProperty("isActive")
private String isActive;
@JsonProperty("displayName")
private String displayName;
@JsonProperty("itemGuid")
private String itemGuid;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();
public String getIsActive() {
return isActive;
}
public String getDisplayName() {
return displayName;
}
public String getItemGuid() {
return itemGuid;
}
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}
@JsonSetter("isActive")
public void setIsActive(String isActive) {
this.isActive = isActive;
}
@JsonSetter("displayName")
public void setDisplayName(String displayName) {
this.displayName = displayName;
}
@JsonSetter("itemGuid")
public void setItemGuid(String itemGuid) {
this.itemGuid = itemGuid;
}
@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
@Override
public String toString() {
return "[ isActive=" + isActive + ", displayName=" + displayName + ", itemGuid=" + itemGuid + " ]";
}
}
Now, this is working as far as mapping the JSON, but, I get ( as expected - the toString() method in the mapping class) a long string of the requested values.
BodyType:String, Body:[ isActive=true, displayName=BC101_Compressor, itemGuid=50480a32-cd65-4b93-94f8-4ba50cf6dec5 ][ isActive=true, displayName=BC102_Compressor, itemGuid=49380230-99eb-4fee-a9a3-e187e4c658ee ][ isActive=true, displayName=BC104_Expander, itemGuid=05d52eb9-6d45-4683-bff2-e079d1d2f745 ][ isActive=true, displayName=BC105_Steam_Turbine, itemGuid=1ddeae49-07ab-4872-817d-ba1dc1528fa2 ][ isActive=true, displayName=BC901_Steam_Turbine, itemGuid=b4acecbb-fac1-4a99-ab95-24e1bc7f4286 ][ isActive=true, displayName=BCG101_Gearbox, itemGuid=49366bcc-bb6a-426f-8c5c-6d65d675ac90 ][ isActive=true, displayName=BCG102_Gearbox, itemGuid=f4402fb9-a638-46e1-93d3-bcb927c44ee4 ][ isActive=true, displayName=BCG901_Gearbox, itemGuid=cd46fc06-dc08-42c7-a73e-839d3b27d683 ][ isActive=true, displayName=BCM101_Motor, itemGuid=6cf41883-36c1-4eca-8325-54588982bdc8 ][ isActive=true, displayName=BCM102_Motor, itemGuid=652e4041-3c2b-410a-8ba0-12a2a53ec730 ][ isActive=true, displayName=BCM901_Generator, itemGuid=96de09f5-6dac-... [Body clipped after 1000 chars, total length is 1677]
I know it is my implementation or mapping, I cannot figure out at this time how to get an Array of Classes from the JSON unmarshalling. thank you for your help!
THIS IS the Blueprint/Spring XML
<!-- GET Asset and Asset tag List for Customer Project Implementation -->
<route autoStartup="true" id="get.impl.assets">
<!-- every 5 minutes -->
<from id="get.assets" uri="timer://getassets?fixedRate=true&period=150000"/>
<process id="a1" ref="assetEntitesProcessor"/>
<choice id="c1">
<when id="w1">
<ognl>request.headers.PDXDB == true</ognl>
<process id="a2" ref="assetTokenProcessor"/>
<choice id="c2">
<when id="w2">
<ognl>request.headers.TKNDB == true</ognl>
<process id="a3" ref="assetUploadProcessor"/>
<setHeader headerName="CamelHttpUri" id="h1">
<simple>${header.UPLOADURL}</simple> <!-- <simple>${header.UPLOADURL}?throwExceptionOnFailure=false</simple> -->
</setHeader>
<setHeader headerName="CamelHttpMethod" id="h2">
<constant>GET</constant>
</setHeader>
<to id="get1" uri="http4://apm-timeseries-query-svc-prod.app-api.aws-usw02-pr.predix.io:443/v2/time_series/upload?throwExceptionOnFailure=false"/>
<unmarshal id="JsonAssets" ref="AssetEntitiesPojo"/>
<process id="p1" ref="getAssets"/>
<!-- TODO extract elements of AssetEntities
<split id="as1" strategyRef="tsAggregationStrategy" streaming="true">
<simple>${body}</simple>
<log id="al6" loggingLevel="INFO" message="Split line ${body}"/>
<process id="p1" ref="getAssets"/>
</split>
-->
<log id="l1" loggingLevel="INFO" message="HTTP4 Upload Response: ${body}"/>
<convertBodyTo id="c1" type="java.lang.String"/>
<to id="t1" uri="{{afteruploadLocation}}"/>
</when>
</choice>
</when>
</choice>
</route>
2 answers
solution1
1 ACCPTED 2019-08-27 23:22:54
尝试：
List<AssetEntities> list = new ObjectMapper().readValue(input, new TypeReference<List<AssetEntities>> {})
solution2
0 2019-08-28 19:03:20
Thank you Fracdroid, yes, your answer works perfectly. I was under the impression that the DataFormats useList would somehow do this. so here is the result. I broke expression up to resolve dependencies.
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.MappingIterator;
import com.fasterxml.jackson.core.type.TypeReference;
public class JsonMapperAssets implements Processor {
private static Logger log = LoggerFactory.getLogger(JsonMapperAssets.class.getName());
@Override
public void process(Exchange exchange) throws JsonParseException, JsonMappingException, IOException {
log.info("JSON Mapper of Assets :: Start");
ObjectMapper mapper = new ObjectMapper();
ObjectReader reader = mapper.reader().forType(new TypeReference<List<AssetEntities>>(){});
List<AssetEntities> jsonAsssetsList = reader.readValue(exchange.getIn().getBody(String.class));
exchange.getIn().setBody(jsonAsssetsList);
log.info("JSON Mapper of Assets :: finish");
}
Now I can use the Camel Splitter EIP
<route autoStartup="true" id="get.impl.assets">
<from id="get.assets" uri="timer://getassets?fixedRate=true&period=150000"/>
<process id="a1" ref="assetEntitesProcessor"/>
<choice id="c1">
<when id="w1">
<ognl>request.headers.PDXDB == true</ognl>
<process id="a2" ref="assetTokenProcessor"/>
<choice id="c2">
<when id="w2">
<ognl>request.headers.TKNDB == true</ognl>
<process id="a3" ref="assetUploadProcessor"/>
<setHeader headerName="CamelHttpUri" id="h1">
<simple>${header.UPLOADURL}</simple>
</setHeader>
<setHeader headerName="CamelHttpMethod" id="h2">
<constant>GET</constant>
</setHeader>
<to id="get1" uri="http4://apm-timeseries-query-svc-prod.app-api.aws-usw02-pr.predix.io:443/v2/time_series/upload?throwExceptionOnFailure=false"/>
<log id="l1" loggingLevel="INFO" message="JSON Response: ${body}"/>
<convertBodyTo id="c1" type="java.lang.String"/>
<process id="jsonmapperassets" ref="jsonMapperAssets" />
<split id="as1" strategyRef="tsAggregationStrategy" streaming="true">
<simple>${body}</simple>
<log id="al6" loggingLevel="INFO" message="Split line ${body}"/>
<process id="p1" ref="getAssets"/>
</split>
<log id="l2" loggingLevel="INFO" message="HTTP4 Upload Response: ${body}"/>
<to id="t1" uri="{{afteruploadLocation}}"/>
</when>
</choice>
</when>
</choice>
</route>
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