I have a JSON object that is dynamically defined.
{
"lvars": {
"task1": {
"assigned" : true,
"params": {//any key value maps here}, {//any key value maps}
},
"task2": {
"assigned" : false,
"params": {//any key value maps here}, {//any key value maps}
....
},
"mvars": {
"Id": {
"type": "String",
"value": ""
},
}
}
Now in java when I am deserializing it into code it becomes somewhat like this,
Map<String, Map<String, Map<String, Map<String, Map<String, Object>>>>> m = ObjectMapper
.fromJson(getValues(), new TypeReference<>() {});
In this case "lvars" and "mvars" are fixed keys and evrything else is variable. How can I avoid the nested map of maps declaration in Java.
Just do:
Map<String,Object> data = ObjectMapper.fromJson(getValues(), new TypeReference<>() {});
Map<String, Map<String, Map<String,Object>>> dynamic_map_0 = (Map<String, Map<String, Map<String, Object>>>) data.get("lvars");
Map<String, Map<String, Map<String,Object>>> dynamic_map_1 = (Map<String, Map<String, Map<String, Object>>>) data.get("mvars");
or simpler:
JSONObject obj = new JSONObject(inputAsString);
JSONObject dynamic0 = obj.getJSONObject("lvars");
JSONObject dynamic1 = obj.getJSONObject("mvars");
You can create a class called NestedMap which is a data structure that contains references to other NestedMap objects, like so:
class NestedMap<K, Object> {
Map<K, NestedMap<K>> data;
Object object; // object to resort to if reached the end of "map-chain"
...
}
This makes the nesting a bit less messy.
Related
I have a list of java objects as below:
[
{
id: "frwfhfijvfhviufhbviufg",
country_code: "DE",
message_key: "key1",
translation: "This is the deutsch translation"
},
{
id: "dfregregtegetgetgttegt",
country_code: "GB",
message_key: "key1",
translation: "This is the uk translation"
},
{
id: "frffgfbgbgbgbgbgbgbgbg",
country_code: "DE",
message_key: "key2",
translation: "This is the again deutch translation"
}
]
How can I convert this into a Map<String, Map<String, String>> like below:
{
"DE": {
"key1": "This is the deutsch translation",
"key2": "This is the again deutch translation"
},
"GB": {
"key1": "This is the uk translation"
}
}
I am new to java and below is my code but the code is not correct:
Map<String, Translations> distinctTranslations = customTranslationsEntities
.stream().collect(Collectors.groupingBy(
CustomTranslationsEntity::getCountryCode,
Collectors.toMap(
CustomTranslationsEntity::getMessageKey,
CustomTranslationsEntity::getTranslation),
)))
where Translations is proto buffer message like below:
message Translations {
map<string, string> translations = 1;
}
Here map<string, string> translations means map like "key1", "This is the deutsch translation"...like this.
The output should be Map<String, Map<String,String>>:
Map<String, Map<String,String>>
distinctTranslations = customTranslationsEntities
.stream()
.collect(Collectors.groupingBy(CustomTranslationsEntity::getCountryCode,
Collectors.toMap(
CustomTranslationsEntity::getMessageKey,
CustomTranslationsEntity::getTranslation,
(v1,v2)->v1)));
I added a merge function, in case there are duplicate keys.
If you want to do it without using streams then
private List<MyObject> list = // Your object List
private Map<String, Map<String, String>> map = new HashMap<>();
for(MyObject object : list){
Map<String, String> localMap;
localMap = map.getOrDefault(object.country_code, new HashMap<>());
localMap.put(object.message_key, object.translation);
if(!map.containsKey(object.country_code)){
map.put(object.country_code, localMap);
}
}
I have a List of Map that i want to group it by the key nom using java streams.
[
{
"dateDebut": "2018-07-01T00:00:00.000+0000",
"nom": "Julien Mannone",
"etat": "Impayé"
},
{
"dateDebut": "2018-08-01T00:00:00.000+0000",
"nom": "Julien Mannone",
"etat": "Impayé"
},
{
"dateDebut": "2018-10-01T00:00:00.000+0000",
"nom": "Mathiew Matic",
"etat": "payé"
},
{
"dateDebut": "2018-10-01T00:00:00.000+0000",
"nom": "Ash Moon",
"etat": "payé"
}
]
so i want as a result something like this
{
"Julien Mannone":[
{
"dateDebut":"2018-07-01T00:00:00.000+0000",
"etat":"Impayé"
},
{
"dateDebut":"2018-08-01T00:00:00.000+0000",
"etat":"Impayé"
}
],
"Mathiew Matic":[
{
"dateDebut":"2018-10-01T00:00:00.000+0000",
"etat":"payé"
}
],
"Ash Moon":[
{
"dateDebut":"2018-10-01T00:00:00.000+0000",
"etat":"payé"
}
]
}
As a beginner in using streams I have made some research I found some codes like that
Map<String, List<Map>> afterFormatting =
beforeFormatting.stream()
.flatMap(m -> m.entrySet().stream())
.collect(groupingBy(Map.Entry::getKey, mapping(Map.Entry::getValue, toList())));
but that doesn't do the job for me
Seems like you're simply looking for:
Map<String, List<Map<String, String>>> afterFormatting =
beforeFormatting.stream()
.collect(Collectors.groupingBy(map -> map.get("nom")));
or if you don't want each Map<String, String> in the result set to contain the "nom" entry then you can do as follows:
Map<String, List<Map<String, String>>> afterFormatting =
beforeFormatting.stream()
.collect(Collectors.groupingBy(map -> map.get("nom"),
Collectors.mapping(map -> {
Map<String, String> temp = new HashMap<>(map);
temp.remove("nom");
return temp;
}, Collectors.toList())));
If I understand you correct you have a maps like
{
"dateDebut": "2018-07-01T00:00:00.000+0000",
"nom": "Julien Mannone",
"etat": "Impayé"
},
but then, when you call
.flatMap(m -> m.entrySet().stream())
You get a stream of all entry sets for all maps.
But actually, your maps are not maps itself. They are rather POJO objects.
I suggest creating a class like
class Value {
String dateDebut, String nom, Etring etat;
// constructor
}
then convert each map to this class:
beforeFormatting.stream()
.map(m-> new Value(m.get("dateDebut"), m.get("nom"),m.get("etat"))
So now, you have a stream<Value> and you can easily group by in by "nom"
.collect(groupingBy(Value::getNom)
You just need to map stream to change the format to needed, and then collect:
list.stream().map(it -> {
Map<String, Map<String, String>> newMap = new HashMap<>();
String nom = it.get("nom");
it.remove("nom");
newMap.put(nom, it);
return newMap;
}
).collect(Collectors.toList())
Testable code:
Map<String, String> m = new HashMap<>();
m.put("dateDebut", "2018-07-01T00:00:00.000+0000");
m.put("nom", "Julien Mannone");
m.put("etat", "Impayé");
Map<String, String> m2 = new HashMap<>();
m2.put("dateDebut", "2018-10-01T00:00:00.000+0000");
m2.put("nom", "Mathiew Matic");
m2.put("etat", "payé");
Map<String, String> m3 = new HashMap<>();
m3.put("dateDebut", "2018-07-01T00:00:00.000+0000");
m3.put("nom", "Ash Moon");
m3.put("etat", "payé");
List<Map<String, String>> list = new ArrayList<>();
list.add(m);
list.add(m2);
list.add(m3);
List<Map<String, Map<String, String>>> res = list.stream().map(it -> {
Map<String, Map<String, String>> newMap = new HashMap<>();
String nom = it.get("nom");
it.remove("nom");
newMap.put(nom, it);
return newMap;
}
).collect(Collectors.toList());
System.out.println(res);
I have a json response like this
{
"queryPath": "/api/",
"nId": "f084f5ad24fcfaa9e9faea0",
"statusCode": 707
"statusMessage": "Success",
"results": {
"data": [
{
"id": "10248522500798",
"capabilities": [
"men",
"women"
],
"name": "errt2"
},
{
"id": "418143778",
"capabilities": [
"dog",
"cat"
],
"name": "Livin"
}
]
}
}
Here am adding results.data to a list as follows
private List<HashMap<String, String>> episodes = new ArrayList<HashMap<String, String>>();
episodes =helper.getJSONValue(response, "results.data");
public <T>T getJSONValue(Response res, String path ){
String json = res.asString();
JsonPath jpath = new JsonPath(json);
return jpath.get(path);
}
so episodes contains all data i mean all results.data
While i debuging am getting this way
[{id=10248522500798, name=errt2, capabilities=[men, women]}, {id=418143778, name=Livin, capabilities=[dog, cat]}]
Here i have capabilities [men, women] and [dog, cat].i need to check capability contains men or dog.
How can i do that?
If i were you i haven't done this..
Use gson and map your json into a java model. It's way better. Afterwards you can access all your model parts with getters and setters.
MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2
As you see it's very simple :)
But if you want to iterate a list that contains a map you can use code block below:
List<Map<String, String>> test = new ArrayList<Map<String, String>>();
for( Map<String, String> map : test ){
for( Entry<String, String> entry : map.entrySet() ){
System.out.println( entry.getKey() + " : " + entry.getValue() );
}
}
With the code above you can get all the entry's keys and values and check them.
Edit:
You have to change your List to List<Map<String,Object>> after that:
List<Map<String, Object>> test = new ArrayList<Map<String, Object>>();
for( Map<String, Object> map : test ){
for( Entry<String, Object> entry : map.entrySet() ){
if( entry.getKey().equalsIgnoreCase( "capabilities" ) ){
List<String> myCapabilities = ( List )entry.getValue();
if( myCapabilities.contains( "dog" ) && myCapabilities.contains( "cat" ) ){
// BLA BLA
}
}
}
}
It's a nasty way.. I recommend you to use gson..
I'd like to convert
Map<long,long> myMap to
myMap : [{"key": 1, "value": 100},
"key": 2, "value": 200}}
Is it possible? I am using Jackson and default behaviour is:
myMap : [{"1" : 100},
"2" : 200}}
It's not possible with a map. However you can create a custom class with key and value as fields and then populate a Collection with instances of that class. On JSON serialization with Jackson the result will be the way you want it.
try this:
ObjectMapper mapper = new ObjectMapper();
String json = "";
Map<String, String> map = new HashMap<String, String>();
map.put("name", "mkyong");
map.put("age", "29");
//convert map to JSON string
json = mapper.writeValueAsString(map);
I am using GSON to serialize Java object.
I have a Java class with following properties.
String property1;
Map<String, HashMap> property2 = new HashMap<>();
Map<String, ArrayList<String>> property3 = new HashMap<>();
Map<String, String[]> property4 = new HashMap<>();
I want to convert this to Json. Because of the maps with HashMaps inside, it has become difficult. I know I can get Json of a map with gsonObject.toJson(map). But I want all these properties in the Json Object. (all in one. not Concatenating many objects)
Can anyone help me to get this done?
I don't see what the problem is. Gson can serialize Maps just fine.
Assuming your class is named Test
Test test = new Test();
test.property1 = "some value";
HashMap<String, Integer> map = new HashMap<>();
map.put("one", 1);
map.put("fourty two", 42);
test.property2.put("property2-key", map);
ArrayList<String> strings = new ArrayList<>(Arrays.asList("string1",
"string2", "string3"));
test.property3.put("property3-key", strings);
String[] stringArray = { "array1", "array2", "array3" };
test.property4.put("property4-key", stringArray);
Gson gson = new Gson();
String json = gson.toJson(test);
System.out.println(json);
It generates the following
{
"property1": "some value",
"property2": {
"property2-key": {
"fourty two": 42,
"one": 1
}
},
"property3": {
"property3-key": [
"string1",
"string2",
"string3"
]
},
"property4": {
"property4-key": [
"array1",
"array2",
"array3"
]
}
}