Java get nested value from ResponseEntity without creating a pojo - java

I am trying to get a single nested value from a ResponseEntity but I am trying to do so without having to create a pojo for every possible item as this is a third party api response.
Example response.getBody() as it appears in Postman:
{
"message": "2 records found",
"records": [
{
"Account": {
"Id": "1",
"Name": "Foo Inc"
},
"CaseNumber": "200",
"Contact": {
"FirstName": "Foo",
"LastName": "Bar"
},
"Status": "In Progress",
"StatusMessage": "We are working on this."
},
{
"Account": {
"Id": "1",
"Name": "Foo Inc"
},
"CaseNumber": "100",
"Contact": {
"FirstName": "Foo",
"LastName": "Bar"
},
"Status": "Closed"
}
]
}
Basically, if I were in JS, I am looking for:
for(let record of res.body.records){
if(record && record.CaseNumber === "200"){
console.log(record.Status)
}
res.body.records[0].Status
Currently, they are are doing this to check if the response is empty:
ResponseEntity<Object> response = restTemplate.exchange(sfdcURL, HttpMethod.POST, entity, Object.class);
LinkedHashMap<Object, Object> resMap = (LinkedHashMap<Object, Object>) response.getBody();
List<Object> recordsList = (List<Object>) resMap.get("records");
if (recordsList.size() <= 0) { return error }
But I need to get the value of of "Status" and I need to do so without creating a pojo.
I appreciate any guidance on how I can do this in Java
UPDATE
So the response.getBody() is returned and when it is displayed in Postman, it looks like the pretty JSON shown above. However, when I do:
System.out.println(response.getBody().toString())
it looks like:
{message=2 Records Found, records=[{Account={Id=1, Name=Foo Inc}, CaseNumber=200, Contact={FirstName=Foo, LastName=Bar}, //etc
To make it worse, one of the fields appears in the console as follows (including linebreaks):
[...], Status=In Progress, LastEmail=From: noreply#blah.com
Sent: 2022-08-08 10:14:54
To: foo#bar.com
Subject: apropos case #200
Hello Foo,
We are working on your case and stuff
Thank you,
us, StatusMessage=We are working on this., OtherFields=blah, [...]
text.replaceAll("=", ":") would help some, but won't add quotations marks nor would it help separate that email block.
How can I so that the responses here like ObjectMapper and JSONObject can work?

You can either convert the string to valid json (not that trivial) and deserialise into a Map<String, Object>, or just pluck the value out of the raw string using regex:
String statusOfCaseNumber200 = response.getBody().toString()
.replaceAll(".*CaseNumber=200\\b.*?\\bStatus=([^,}]*).*", "$1");
This matches the whole string, captures the desired status value then replaces with the status, effectively "extracting" it.
The regex:
.*CaseNumber=200\b everything up to and including CaseNumber=200 (not matching longer numbers like 2001)
.*? as few chars as possible
\\bStatus= "Status=" without any preceding word chars
([^,}]*) non comma/curly brace characters
.* the rest
It's not bulletproof, but it will probably work for your use case so it doesn't need to be bulletproof.
Some test code:
String body = "{message=2 Records Found, records=[{Account={Id=1, Name=Foo Inc}, CaseNumber=200, Contact={FirstName=Foo, LastName=Bar}, Status=In Progress, StatusMessage=We are working on this.}, {Account={Id=1, Name=Foo Inc}, CaseNumber=100, Contact={FirstName=Foo, LastName=Bar}, Status=Closed}]";
String statusOfCaseNumber200 = body.replaceAll(".*CaseNumber=200\\b.*?\\bStatus=([^,}]*).*", "$1");
System.out.println(statusOfCaseNumber200); // "In Progress"

PLEASE DO NOT use Genson as Hiran showed in his example. The library hasn't been updated since 2019 and has many vulnerable dependencies!
Use Jackson or Gson.
Here how you can serialize a string into a Jackson JsonNode:
ObjectMapper mapper = new ObjectMapper();
String json = ...;
JsonNode node = mapper.readTree(json);
If you want to serialize a JSON object string into a Map:
ObjectMapper mapper = new ObjectMapper();
String json = ...;
Map<String, Object> map = mapper.readValue(json, HashMap.class);
You can read more about JsonNode here and a tutorial here.

You can use JSON-Java library and your code will look like this:
JSONObject jsonObject = new JSONObject(JSON_STRING);
String status = jsonObject.getJSONArray("records")
.getJSONObject(0)
.getString("Status");
System.out.println(status);
Or in a loop
JSONArray jsonArray = new JSONObject(jsonString).getJSONArray("records");
for(int i =0; i < jsonArray.length(); i++) {
String status = jsonArray
.getJSONObject(i)
.getString("Status");
System.out.println(status);
}

So the response.getBody() is returned and when it is displayed in Postman, it looks like the pretty JSON shown above. However, when I do:
...
text.replaceAll("=", ":") would help some, but won't add quotations
marks nor would it help separate that email block.
How can I so that the responses here like ObjectMapper and JSONObject
can work?
Firstly, Jackson is the default message converter which Spring Web uses under the hood to serialize and deserialize JSON. You don't need to introduce any dependencies.
Secondly, the process serialization/deserialization is handled by the framework automatically, so that in many cases you don't need to deal with the ObjectMapper yourself.
To emphasize, I'll repeat: in most of the cases in Spring you don't need to handle raw JSON yourself. And in the body of ResponseEntiry<Object> produced by the method RestTemplate.exchange() you have a LinkedHashMap in the guise of Object, it's not a raw JSON (if you want to know why it is a LinkedHashMap, well because that's how Jackson stores information, and it's a subclass of Object like any other class in Java). And sure, when you're invoking toString() on any implementation of the Map you'll get = between a Key and a Value.
So, the problem you've mentioned in the updated question is artificial.
If you want to deal with a Map instead of an object with properly typed properties and here's how you can do that:
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<LinkedHashMap<String, Object>> response = restTemplate.exchange(
sfdcURL, HttpMethod.POST, entity, new ParameterizedTypeReference<>() {}
);
Map<String, Object> resMap = response.getBody();
List<Object> recordsList = (List<Object>) resMap.get("records");
if (recordsList.isEmpty()) { ... }
If there are redundant lines in the Values which you want to trim, then as a remedy you can introduce a custom Jackson-module declaring a Deserializer which would handle leading/trailing white-space and new lines, described in this answer. Deserialize in the module would be applied by default, other options would require creating classes representing domain objects which you for some reasons want to avoid.

As Oliver suggested JsonNode seems to be the best approach. But, if I receive the ResponseEntity<Object>, I still cannot figure out a way to convert it to readable Json (and thus convert it to JsonNode), so I am still open to responses for that part.
I was able to get it to work by changing the ResponseEntity<Object> to ResponseEntity<JsonNode> so this is what I will be submitting for now:
ResponseEntity<JsonNode> response = restTemplate.exchange(sfdcURL,
HttpMethod.POST, entity, JsonNode.class);
JsonNode records = response.getBody().get("records");
String status = null;
String statusMessage = null;
for (JsonNode rec : records) {
if(rec.get("CaseNumber").asText().equals(caseNumber)) {
status = rec.get("Status").asText();
if(rec.has("StatusMessage")) {
statusMessage = rec.get("StatusMessage").asText();
}
} else {
statusMessage = "Invalid CaseNumber";
}
}
Because the overall method returns a ResponseEntity<Object> I then converted my strings to a HashMap and returned that:
HashMap<String, String> resMap = new HashMap<String, String>();
resMap.put("Status", status);
resMap.put("StatusMessage", statusMessage);
return new ResponseEntity<>(resMap, HttpStatus.OK);
This is not a perfect solution, but it works for now. Would still be better for exception handling if I could receive a ResponseEntity<Object> and then convert it to a JsonNode though. Thanks everyone for the responses!

Related

How to extract values from a String that cannot be converted to Json

While processing the DialogFlow Response object, I get the below given string as textPayload. If this is a Json string, I can easily convert it to a JSONObject and then extract the values. However, could not convert this to a Json Object. How do I get the values for the keys in this string? What is a good way to parse this string in Java?
String to be processed
Dialogflow Response : id: "XXXXXXXXXXXX"
lang: "en"
session_id: "XXXXX"
timestamp: "2020-04-26T16:38:26.162Z"
result {
source: "agent"
resolved_query: "Yes"
score: 1.0
parameters {
}
contexts {
name: "enaccaccountblocked-followup"
lifespan: 1
parameters {
}
}
metadata {
intent_id: "XXXXXXXXXXXX"
intent_name: "EN : ACC : Freezing Process - Yes"
end_conversation: true
webhook_used: "false"
webhook_for_slot_filling_used: "false"
is_fallback_intent: "false"
}
fulfillment {
speech: "Since you have been permanently blocked, please request to unblock your account"
messages {
lang: "en"
type {
number_value: 0.0
}
speech {
string_value: "Since you have been permanently blocked, please request to unblock your account."
}
}
}
}
status {
code: 200
error_type: "success"
}
Convert it to valid json, then map using one of the many libraries out there.
You'll only need to:
replace "Dialogflow Response :" with {
add } to the end
add commas between attributes, ie
at the end of every line with a ":"
after "}", except when the next non-whitespace is also "}"
Jackson (at least) can be configured to allow quotes around attribute names as optional.
Deserializing to a Map<String, Object> works for all valid json (except an array, which this isn't).
If I understand you correctly the issue here is that the keys do not have quotations marks, hence, a JSON parser will reject this.
Since the keys all start on a new line with some white-space and all end with a colon : you can fix this easily with a regular expression.
See How to Fix JSON Key Values without double-quotes?
You can then parse it to a Map via
Map<String, Object> map
= objectMapper.readValue(json, new TypeReference<Map<String,Object>>(){});
(but I assume you are aware of this).
Create a class for TextPayload object like this.
public class TextPayload {
private int session_id;
private String lang;
private String timestamp;
private String[] metadata ;
//Other attributes
//getters setters
}
Then using an ObjectMapper extract the values from textpayload like this:
ObjectMapper mapper = new ObjectMapper();
TextPayload textPayload = mapper.readValue(output, User.class);
To utilize ObjectMapper and hands on with it follow this
you can use the nodejs package parse-dialogflow-log to parse the textResponse string.
replace "Dialogflow Response :" with "{"
add "}" to the end
run the package on the result and you'll get a nice json.

How can I send an object as part of the JSON Web Token?

I'm trying to create a web token using the jjwt library, but I can't figure out how to send an object as one of the claims. If I parse the object or manually create the string the entire string is coming through as the value instead of a separate JSON object. For instance, I want to send something that looks like this:
{
"iss": "NQoFK1NLVelFWOBQtQ8A",
"iat": 1511963669,
"user": {
"id": "exampleuser",
"email": "example#mail.com",
"name": "A User",
}
}
But all I've been able to create is:
{
"iss": "NQoFK1NLVelFWOBQtQ8A",
"iat": 1511963669,
"user": "{\"id\": \"example#mail.com\",\"email\": \"example#mail.com\",\"name\": \"A User\"}"
}
Welcome to StackOverflow!
This feature will be natively supported by JJWT when using Jackson in the upcoming JJWT 0.11.0 release (and you can read the docs for this feature too). But it is not available natively in 0.10.X and earlier.
Prior to 0.11.0, and assuming you're using Jackson, you'll have to do this yourself manually with the ObjectMapper:
// when creating:
User user = getUser();
ObjectMapper objectMapper = new ObjectMapper(); // or use an existing one
String json = objectMapper.writeValueAsString(user);
byte[] bytes = json.getBytes(StandardCharsets.UTF_8)
String base64 = Encoders.BASE64.encode(bytes);
String jws = Jwts.builder()
...
.claim("userJsonBase64", base64)
...
.compact();
//when parsing:
String userJsonBase64 = Jwts.parser()....parseClaimsJws(jws).getBody().get("userJsonBase64", String.class);
bytes = Decoders.BASE64.decode(userJsonBase64);
json = new String(bytes, StandardCharsets.UTF_8);
user = objectMapper.readValue(json, User.class);
Thank you for your answer, that will be a nice feature to have, once it's available. I wanted to follow up and post a workaround that I found, in case it helps anyone else in the meantime. I was able to create the JSON I needed using a Java HashMap (I found out the hard way that a Scala Map does not work) and then passing that as the value of the claim:
val user: util.Map[String, String] = new util.HashMap[String,
String]() user.put("id", email.value) user.put("email", email.value)
user.put("name", name.displayName)
...
val jws: String = Jwts.builder()
.claim("user", user)
.signWith(key).compact()

How do I remove backslashes before quotes from a JSONObject string?

Background
I have a list of strings (records) that are dynamically created by a class. Each record may have different keys (e.g. favorite_pizza on first, favorite_candy on second).
// Note: These records are dynamically created and not stored
// in this way. This is simply for display purposes.
List<String> records =
Arrays.asList(
"{\"name\":\"Bob\",\"age\":40,\"favorite_pizza\":\"Cheese\"}",
"{\"name\":\"Jill\",\"age\":22,\"favorite_candy\":\"Swedish Fish\"}");
The list of records is then passed to a separate HTTP request class.
public Response addRecords(List<String> records) {
...
}
Inside the HTTP request service, I want to build a JSON request body:
{
"records": [
{
"name": "Bob",
"age": 40,
"favorite_pizza": "Cheese"
},
{
"name": "Jill",
"age": 22,
"favorite_candy": "Swedish Fish"
}
]
}
I'm using org.json.JSONObject to add the records key and create the request body:
JSONObject body = new JSONObject();
// Add the "records" key
body.put("records", records);
// Create the request body
body.toString();
Issues
When I run my junit test in IntelliJ, the request body contains a backslash before each quote:
org.junit.ComparisonFailure:
Expected :"{"records":["{"name":"Bob","age":40,"favorite_pizza":"Cheese"}","{"name":"Jill","age":22,"favorite_candy":"Swedish Fish"}"]}"
Actual :"{"records":["{\"name\":\"Bob\",\"age\":40,\"favorite_pizza\":\"Cheese\"}","{\"name\":\"Jill\",\"age\":22,\"favorite_candy\":\"Swedish Fish\"}"]}"
And when I make the request it fails because the body is not formatted correctly:
{
"records": [
"{\"name\":\"Bob\",\"age\":40,\"favorite_pizza\":\"Cheese\"}",
"{\"name\":\"Jill\",\"age\":22,\"favorite_candy\":\"Swedish Fish\"}"
]
}
Questions
Why is JSONObject including the backslashes before each quote?
How do I remove the backslashes?
You are creating a list of string, which is not what you want.
You should instead create a list of objects (Maps)
Map<String, Object> m1 = new LinkedHashMap<>();
m1.put("name", "Bob");
m1.put("age", 40);
m1.put("favorite_pizza", "Cheese");
LinkedHashMap<String, Object> m2 = new LinkedHashMap<>();
m2.put("name", "Jill");
m2.put("age", 22);
m2.put("favorite_candy", "Swedish Fish");
List<LinkedHashMap<String, Object>> records = Arrays.asList(m1,m2);
JSONObject body = new JSONObject();
// Add the "records" key
body.put("records", records);
This is a quite common mistake (it seems), to try to serialize strings formatted like json objects expecting is the same thing as passing a the object itself.
UPDATE:
Or if you have a json serialized object list then ...
List<String> recordSource =
Arrays.asList(
"{\"name\":\"Bob\",\"age\":40,\"favorite_pizza\":\"Cheese\"}",
"{\"name\":\"Jill\",\"age\":22,\"favorite_candy\":\"Swedish Fish\"}");
List<JSONObject> records =
recordSource.stream().map(JSONObject::new).collect(Collectors.toList());
JSONObject body = new JSONObject();
// Add the "records" key
body.put("records", records);
System.out.println(body.toString());
If your record strings are already valid json you can either
Iterate over them, converting them one at a time into a JSONObject (see here) and then add the result to a JSONArray which you can manipulate if needed.
Create the array entirely by hand since it's just comma separated record strings inside square brackets.

(JAVA, Elasticsearch) How can I get fields from SearchResponse?

I just wonder how I get fields from SearchResponse which is result of my query.
Below is my query:
{"size":99,"timeout":"10s","query":{"bool":{"filter":[{"bool":{"must":[{"range":{"LOG_GEN_TIME":{"from":"2018-11-01 12:00:01+09:00","to":"2018-11-01 23:59:59+09:00","include_lower":true,"include_upper":true,"boost":1.0}}},{"wrapper":{"query":"eyAiYm9vbCIgOiB7ICJtdXN0IiA6IFsgeyAidGVybSIgOiB7ICJBU1NFVF9JUCIgOiAiMTAuMTExLjI1Mi4xNiIgfSB9LCB7ICJ0ZXJtIiA6IHsgIkFDVElPTl9UWVBFX0NEIiA6ICIyIiB9IH0sIHsgInRlcm0iIDogeyAiRFNUX1BPUlQiIDogIjgwIiB9IH0gXSB9IH0="}}],"adjust_pure_negative":true,"boost":1.0}}],"adjust_pure_negative":true,"boost":1.0}},"_source":{"includes":["LOG_GEN_TIME","LOG_NO","ASSET_NO"],"excludes":[]},"sort":[{"LOG_GEN_TIME":{"order":"desc"}},{"LOG_NO":{"order":"desc"}}]}
and when I query this, like below:
SearchResponse searchResponse = request.get();
I got right result:
{
"took":1071,
"timed_out":false,
"_shards":{
"total":14,
"successful":14,
"skipped":0,
"failed":0
},
"_clusters":{
"total":0,
"successful":0,
"skipped":0
},
"hits":{
"total":2,
"max_score":null,
"hits":[
{
"_index":"log_20181101",
"_type":"SEC",
"_id":"1197132746951492963",
"_score":null,
"_source":{
"ASSET_NO":1,
"LOG_NO":1197132746951492963,
"LOG_GEN_TIME":"2018-11-01 09:46:28+09:00"
},
"sort":[
1541033188000,
1197132746951492963
]
},
{
"_index":"log_20181101",
"_type":"SEC",
"_id":"1197132746951492963",
"_score":null,
"_source":{
"ASSET_NO":2,
"LOG_NO":1197337264704454700,
"LOG_GEN_TIME":"2018-11-01 23:00:06+09:00"
},
"sort":[
1541080806000,
1197337264704454700
]
}
]
}
}
To use this result, I need to map this by field and value.
I think there's a way to map the field and value to the 'fields' parameter so that we could use it nicely, but I cannot find.
I hope I can use the result like this way:
SearchHit hit = ...
Map<String, SearchHitField> fields = hit.getFields();
String logNo = fields.get("LOG_NO").value();
And It seems like this is the common way to use..
Or am I misunderstanding something? Tell me other way if there's better way, please.
Any comment would be appreciated. Thanks.
I'm not clear what client you are using to query elastic. If you are using elasticsearch high level rest client then you can loop through hits and to get source you can use hit.getSourceAsMap() to get the key value of fields.
For your comment:
Firstly create a POJO class which corresponds to _source (i.e. index properties; the way data is store in elastic)
The use hit.getSourceAsString() to get _source in json format.
Use jackson ObjectMapper to map json to your pojo
Assuming you created a POJO class AssetLog
SearchHit[] searchHits = searchResponse.getHits().getHits();
for (SearchHit searchHit : searchHits) {
String hitJson = searchHit.getSourceAsString();
ObjectMapper objectMapper = new ObjectMapper();
AssetLog source = objectMapper.readValue(hitJson, AssetLog.class);
//Store source to map/array
}
Hope this helps.

Spring RestTemplate, GsonHttpMessageConverter

given JSON
{"news" : [ {...}, {...}, {...} ] }
the array contains custom objects, which I already declared as POJOs. Want I simply want to map my custom objects by keypath "news".
restTemplate.exchange(URI + "/news/{limit}/", HttpMethod.GET, CustomObject[].class, 10)
throws an exception, because this JSON is expected
[ {...}, {...}, {...}]
Is there a way to configure RestTemplate to match my needs?
Regards
Update:
restTemplate.exchange(URI + "/news/{limit}/", HttpMethod.GET, requestEntity, JsonElement.class,10).getBody().getAsJsonObject().get("news");
CustomObject[] result = gson.fromJson(body, CustomObject[].class);
This snippet works but is there a cleaner way? For my suprise mapping to JSONObject doesn't even worked, JSONElement did the job at the end.
Well I'll add my update in here to close this question. If someone can provide a cleaner solution I'll be happy to accept it:
restTemplate.exchange(URI + "/news/{limit}/", HttpMethod.GET, requestEntity, JsonElement.class,10).getBody().getAsJsonObject().get("news");
CustomObject[] result = gson.fromJson(body, CustomObject[].class);
This snippet works but is there a cleaner way? For my suprise mapping to JSONObject doesn't even worked, JSONElement did the job at the end.

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