How to sort GSON Array based on a key? - java

Consider the following is my Array
[
{"id":10,"name":"name10","valid":true},
{"id":12,"name":"name12","valid":false},
{"id":11,"name":"name11","valid":false},
{"id":9,"name":"name9","valid":true}
]
Created a JsonArray out of it, like following code does:
//Create a JSON Parser using GSON library
objJsonParser = new JsonParser();
String strArrayText = [{"id":9,"name":"name9","valid":true}, ...]
JsonArray jsonArrayOfJsonObjects = objJsonParser.parse(strArrayText).getAsJsonArray();
Now, I am trying to sort jsonArrayOfJsonObjects based on name field.
Desired Output:
[
{"id":9,"name":"name9","valid":true},
{"id":10,"name":"name10","valid":false},
{"id":11,"name":"name11","valid":false},
{"id":12,"name":"name12","valid":true}
]
Could anyone help to sort this out with best apporach with respect to Java & Gson?
Your inputs are greatly appreciated.

First of all, the proper way to parse your JSON is to create a class to encapsulate your data, such as:
public class MyClass {
private Integer id;
private String name;
private Boolean valid;
//getters & setters
}
And then:
Type listType = new TypeToken<List<MyClass>>() {}.getType();
List<MyClass> myList = new Gson().fromJson(strArrayText, listType);
Now you have a List and you want to sort it by the value of the attribute id, so you can use Collections as explained here:
public class MyComparator implements Comparator<MyClass> {
#Override
public int compare(MyClass o1, MyClass o2) {
return o1.getId().compareTo(o2.getId());
}
}
And finally:
Collections.sort(myList, new MyComparator());

Try this library method as a simple JSON-level alternative to model classes creation:
/**
* Sort JSON-array by a given key name (numbers or text expected).
*
* #param jsonArray JSON-array to sort.
* #param keyNameToSort Key name to sort by. Expected are integer type
* (sorted ascending) or string type (sorted
* alphabetically).
*/
public static JsonArray
sortJsonArrayByKey(
JsonArray jsonArray,
String keyNameToSort) {
JsonArray sortedJsonArray = new JsonArray();
JsonObject jsonObject = null;
int jsonElementIndex;
TreeMap<Integer, JsonObject> integerSortedObjects = new TreeMap<>();
TreeMap<String, JsonObject> stringSortedObjects = new TreeMap<>();
for (
jsonElementIndex = 0;
jsonElementIndex < jsonArray.size();
jsonElementIndex++) {
try {
// A JSON-Object from JSON-array:
jsonObject =
jsonArray
.get(
jsonElementIndex)
.getAsJsonObject();
} catch (Exception notAnObject) {
}
for (Entry<String, JsonElement> entry : jsonObject.entrySet()) {
// Look for the given key in the JSON-object:
if (
entry.getKey()
.equals(keyNameToSort)) {
try {
// If key is of integer type:
integerSortedObjects.put(
entry
.getValue()
.getAsInt(),
jsonObject);
} catch (Exception notAnInt) {
try {
// If key is of string type:
stringSortedObjects.put(
entry
.getValue()
.getAsString(),
jsonObject);
} catch (Exception neitherIntNorString) {
}
}
}
}
}
// Add sorted by number values first:
for (Integer key : integerSortedObjects.keySet()) {
sortedJsonArray.add(
integerSortedObjects.get(
key));
}
// Add sorted by string values second:
for (String key : stringSortedObjects.keySet()) {
sortedJsonArray.add(
stringSortedObjects.get(
key));
}
return sortedJsonArray;
}

you can use Gson library https://sites.google.com/site/gson/gson-user-guide
to get the Array(the class should implement comparable) and sort with arrays.sort();
Thanks

Related

How to add two maps to the List

Code is:
How can to add the Map to the List
public List<Map<Object, Object>> getReportees(String idOfEmp) throws Exception {
JSONArray jsonarr_s = (JSONArray) jobj.get("list");
Map<Object, Object> map = new HashMap<Object, Object>();
if (jsonarr_s.size() > 0) {
// Get data for List array
for (int i = 0; i < jsonarr_s.size(); i++) {
JSONObject jsonobj_1 = (JSONObject) jsonarr_s.get(i);
JSONObject jive = (JSONObject) jsonobj_1.get("jive");
Object names = jsonobj_1.get("displayName");
Object userid = jive.get("username");
map.put(names, userid); //return the map with the key value pairs
map = new HashMap<Object, Object>();
String UserId = userid.toString();
String output1 = resp1.getEntity(String.class);
JSONObject jobjs = (JSONObject) new JSONParser().parse(output1);
// Store the JSON object in JSON array as objects (For level 1 array element i.e
// issues)
JSONArray jsonarr_new = (JSONArray) jobjs.get("issues");
int numofjiras = jsonarr_new.size(); //this jira count must be mapped to the name and id
map.put("count", numofjiras);
}
return map;
} else {
map.put("errorcheck", msg);
}
return map;
}
}
I want the output like:
Name id count
AJ 235457 2
Geet 637571 0
Actually I am getting the Name and id in key value pairs.Then I am trying to pass each id to an api which will give me the count.So how can I return all the fileds i.e Name ,id and count.So here I am trying to map like for this Userid and Name this is the count.How can we acheive it.Plesae help.Thanks in advnce.
I think you can try creating a new class to represent each row in your output. For example, you can create an Employee class like this:
public class Employee {
private long id;
private String name;
private int issueCount;
//getters and setters
}
You can, then, use this class and assign the values from the JSONArray arrays to it. Once you get the value for "count", you can just add the Employee object to the map (or list).
Hope this helps.
You would need to declare a local list first and then return that list:
public List<Map<Object, Object>> getReportees(String idOfEmp) throws Exception {
JSONArray jsonarr_s = (JSONArray) jobj.get("list");
Map<Object, Object> map = new HashMap<Object, Object>();
List<Map<Object, Object>> resultList = new ArrayList<Map<Object,Object>>();
if (jsonarr_s.size() > 0) {
// Get data for List array
for (int i = 0; i < jsonarr_s.size(); i++) {
JSONObject jsonobj_1 = (JSONObject) jsonarr_s.get(i);
JSONObject jive = (JSONObject) jsonobj_1.get("jive");
Object names = jsonobj_1.get("displayName");
Object userid = jive.get("username");
map.put(names, userid); //return the map with the key value pairs
String UserId = userid.toString();
String output1 = resp1.getEntity(String.class);
JSONObject jobjs = (JSONObject) new JSONParser().parse(output1);
// Store the JSON object in JSON array as objects (For level 1 array element i.e
// issues)
JSONArray jsonarr_new = (JSONArray) jobjs.get("issues");
int numofjiras = jsonarr_new.size(); //this jira count must be mapped to the name and id
map.put("count", numofjiras);
}
resultList.add(map);
} else {
map.put("errorcheck", msg);
resultList.add(map);
}
return resultList;
}
Based on your results though you should consider flipping your data objects to instead be
Map<Object, List<Object>>
where the first Object in the map which is they key the name and then the list would contain two objects [id, count].

How to get dynamically changed Key's value in Json String using java

I'm trying to parse Json string using java, I have stuck up with some scenario.
See below is my JSON String:
"NetworkSettings": {
"Ports": {
"8080/tcp": [ // It will change dynamically like ("8125/udp" and "8080/udp" etc....)
{
"HostIp": "0.0.0.0",
"HostPort": "8080"
}
]
}
}
I try to parse the above json string by using the following code:
JsonObject NetworkSettings_obj=(JsonObject)obj.get("NetworkSettings");
if(NetworkSettings_obj.has("Ports"))
{
JsonObject ntw_Ports_obj=(JsonObject)NetworkSettings_obj.get("Ports");
if(ntw_Ports_obj.has("8080/tcp"))
{
JsonArray arr_ntwtcp=(JsonArray)ntw_Ports_obj.get("8080/tcp");
JsonObject ntwtcp_obj=arr_ntwtcp.get(0).getAsJsonObject();
if(ntwtcp_obj.has("HostIp"))
{
ntw_HostIp=ntwtcp_obj.get("HostIp").toString();
System.out.println("Network HostIp = "+ntw_HostIp);
}
if(ntwtcp_obj.has("HostPort"))
{
ntw_HostPort=ntwtcp_obj.get("HostPort").toString();
System.out.println("Network HostPort = "+ntw_HostPort);
}
}
else
{
ntw_HostIp="NA";
ntw_HostPort="NA";
}
}
else
{
ntw_HostIp="NA";
ntw_HostPort="NA";
}
In my code I have used this code
JsonArray arr_ntwtcp=(JsonArray)ntw_Ports_obj.get("8080/tcp");
to get the value of "8080/tcp"
How can I get the values of dynamically changing key like ("8125/udp","8134/udp", etc...)
Note: I'm using gson library for parsing
After modification
public static void main(String args[])
{
try
{
JsonParser parser = new JsonParser();
JsonObject obj=(JsonObject)parser.parse(new FileReader("sampleJson.txt"));
System.out.println("obj = "+obj);
JsonObject NetworkSettings_obj=(JsonObject)obj.get("NetworkSettings");
if(NetworkSettings_obj.has("Ports"))
{
JsonObject ntw_Ports_obj=(JsonObject)NetworkSettings_obj.get("Ports");
System.out.println("ntw_Ports_obj = "+ntw_Ports_obj);
Object keyObjects = new Gson().fromJson(ntw_Ports_obj, Object.class);
List keys = new ArrayList();
System.out.println(keyObjects instanceof Map); //**** here the statement prints false
if (keyObjects instanceof Map) // *** so controls doesn't enters into the if() condition block *** //
{
Map map = (Map) keyObjects;
System.out.println("Map = "+map);
keys.addAll(map.keySet());
String key = (String) keys.get(0);
JsonArray jArray = (JsonArray) ntw_Ports_obj.get(key);
System.out.println("Array List = "+jArray);
}
}
}
catch(Exception e)
{
}
}
You can do something like that (not tested but should be ok) :
if (ntw_Ports_obj.isJsonArray()) {
Iterator it = ntw_Ports_obj.getAsJsonArray().iterator();
while (it.hasNext()) {
JsonElement element = (JsonElement) it.next();
if(element.isJsonArray()){
JsonArray currentArray = element.getAsJsonArray();
// Do something with the new JsonArray...
}
}
}
So your problem is the key 8080/tcp is not fixed and it may change. when this situation you can try like this to get the value of the Dynamic key.
Set<Map.Entry<String, JsonElement>> entrySet = ntw_Ports_obj
.entrySet();
for (Map.Entry<String, JsonElement> entry : entrySet) {
String key = entry.getKey();
JsonArray jArray = (JsonArray) ntw_Ports_obj.get(key);
System.out.println(jArray);
}
Edit:
Object keyObjects = new Gson().fromJson(ntw_Ports_obj, Object.class);
List keys = new ArrayList();
/** for the given json there is a one json object within the 'Ports' so the 'keyObjects' will be the 'Map'**/
if (keyObjects instanceof Map) {
Map map = (Map) keyObjects;
keys.addAll(map.keySet());
/**
* keys is a List it may contain more than 1 value, but for the given
* json it will contain only one value
**/
String key = (String) keys.get(0);
JsonArray jArray = (JsonArray) ntw_Ports_obj.get(key);
System.out.println(jArray);
}

How to parse JSON with JAVA when there are random key names

How do I convert some JSON to a POJO when I don't know the name of a key?
This is my POJO:
public class Summoner {
private Details summonerDetails;
public Details getSummonerDetails() {
return summonerDetails;
}
public void setSummonerDetails(Details summonerDetails) {
this.summonerDetails = summonerDetails;
}
}
The Details class have variables like id, name, etc. -> No issues here
This is the line in my Main class where I try to map the JSON to a POJO:
Summoner test = new ObjectMapper().readValue(json, Summoner.class);
this is a JSON response example I receive:
{
"randomName":{
"id":22600348,
"name":"Ateuzz",
"profileIconId":546,
"summonerLevel":30,
"revisionDate":1378316614000
}
}
if my POJO Details member variable name is "randomName", above code will work. but when I get a response with a different name than "randomName", it doesn't. How do I make my code work for random names?
I'm using Jackson
I'm sorry I can't make a little more clear my issue.
I have solution using not only jackson API but with the use of org.json API also.
String str = "{\"randomName\":{\"id\":22600348,\"name\":\"Ateuzz\",\"profileIconId\":546,\"summonerLevel\":30,\"revisionDate\":1378316614000}}";
JSONObject json = new JSONObject(str);
Iterator<?> keys = json.keys();
while(keys.hasNext())
{
String key = (String)keys.next();
Details test = new ObjectMapper().readValue(json.getJSONObject(key).toString(), Details.class);
}
Here i have use another JAVA Json API to convert your string into jsonObject and than iterate it to get your first key value and map that to your class Details.
I assume that your json format is same as you have mention in your question.
May this will help you.
Using Jackson:
String json = "{\"randomName\":{\"id\":22600348,\"name\":\"Ateuzz\",\"profileIconId\":546,\"summonerLevel\":30,\"revisionDate\":1378316614000}}";
try
{
#SuppressWarnings("unchecked")
Map<String, Map<String, Object>> map = (Map) new ObjectMapper().readValue(json, Map.class);
for(String key : map.keySet())
{
Map<String, Object> submap = map.get(key);
System.out.println(key + ":");
for(String k : submap.keySet())
{
System.out.println("\t" + k + ": " + submap.get(k));
}
}
}
catch(IOException e)
{
e.printStackTrace();
}

Convert JSON object with duplicate keys to JSON array

I have a JSON string that I get from a database which contains repeated keys. I want to remove the repeated keys by combining their values into an array.
For example
Input
{
"a":"b",
"c":"d",
"c":"e",
"f":"g"
}
Output
{
"a":"b",
"c":["d","e"],
"f":"g"
}
The actual data is a large file that may be nested. I will not know ahead of time what or how many pairs there are.
I need to use Java for this. org.json throws an exception because of the repeated keys, gson can parse the string but each repeated key overwrites the last one. I need to keep all the data.
If possible, I'd like to do this without editing any library code
As of today the org.json library version 20170516 provides accumulate() method that stores the duplicate key entries into JSONArray
JSONObject jsonObject = new JSONObject();
jsonObject.accumulate("a", "b");
jsonObject.accumulate("c", "d");
jsonObject.accumulate("c", "e");
jsonObject.accumulate("f", "g");
System.out.println(jsonObject);
Output:
{
"a":"b",
"c":["d","e"],
"f":"g"
}
I want to remove the repeated keys by combining their values into an array.
Think other than JSON parsing library. It's very simple Java Program using String.split() method that convert Json String into Map<String, List<String>> without using any library.
Sample code:
String jsonString = ...
// remove enclosing braces and double quotes
jsonString = jsonString.substring(2, jsonString.length() - 2);
Map<String, List<String>> map = new HashMap<String, List<String>>();
for (String values : jsonString.split("\",\"")) {
String[] keyValue = values.split("\":\"");
String key = keyValue[0];
String value = keyValue[1];
if (!map.containsKey(key)) {
map.put(key, new ArrayList<String>());
}
map.get(key).add(value);
}
output:
{
"f": ["g"],
"c": ["d","e"],
"a": ["b"]
}
In order to accomplish what you want, you need to create some sort of custom class since JSON cannot technically have 2 values at one key. Below is an example:
public class SomeClass {
Map<String, List<Object>> values = new HashMap<String, List<Object>>();
public void add(String key, Object o) {
List<Object> value = new ArrayList<Object>();
if (values.containsKey(key)) {
value = values.get(key);
}
value.add(o);
values.put(key, value);
}
public JSONObject toJson() throws JSONException {
JSONObject json = new JSONObject();
JSONArray tempArray = null;
for (Entry<String, List<Object>> en : values.entrySet()) {
tempArray = new JSONArray();
for (Object o : en.getValue()) {
tempArray.add(o);
}
json.put(en.getKey(), tempArray);
}
return json;
}
}
You can then retrieve the values from the database, call the .add(String key, Object o) function with the column name from the database, and the value (as the Object param). Then call .toJson() when you are finished.
Thanks to Mike Elofson and Braj for helping me in the right direction. I only wanted to have the keys with multiple values become arrays so I had to modify the code a bit. Eventually I want it to work for nested JSON as well, as it currently assumes it is flat. However, the following code works for what I need it for at the moment.
public static String repeatedKeysToArrays(String jsonIn) throws JSONException
{
//This assumes that the json is flat
String jsonString = jsonIn.substring(2, jsonIn.length() - 2);
JSONObject obj = new JSONObject();
for (String values : jsonString.split("\",\"")) {
String[] keyValue = values.split("\":\"");
String key = keyValue[0];
String value = "";
if (keyValue.length>1) value = keyValue[1];
if (!obj.has(key)) {
obj.put(key, value);
} else {
Object Oold = obj.get(key);
ArrayList<String> newlist = new ArrayList<String>();
//Try to cast as JSONArray. Otherwise, assume it is a String
if (Oold.getClass().equals(JSONArray.class)) {
JSONArray old = (JSONArray)Oold;
//Build replacement value
for (int i=0; i<old.length(); i++) {
newlist.add( old.getString(i) );
}
}
else if (Oold.getClass().equals(String.class)) newlist = new ArrayList<String>(Arrays.asList(new String[] {(String)Oold}));
newlist.add(value);
JSONArray newarr = new JSONArray( newlist );
obj.put(key,newarr);
}
}
return obj.toString();
}

Merge (Concat) Multiple JSONObjects in Java

I am consuming some JSON from two different sources, I end up with two JSONObjects and I'd like to combine them into one.
Data:
"Object1": {
"Stringkey":"StringVal",
"ArrayKey": [Data0, Data1]
}
"Object2": {
"Stringkey":"StringVal",
"Stringkey":"StringVal",
"Stringkey":"StringVal",
}
Code, using http://json.org/java/ library:
// jso1 and jso2 are some JSONObjects already instantiated
JSONObject Obj1 = (JSONObject) jso.get("Object1");
JSONObject Obj2 = (JSONObject) jso.get("Object2");
So in this situation I'd like to combine Obj1 and Obj2, either to make a totally new JSONObject or concat one to the other. Any ideas besides pulling them all apart and individually adding in by puts?
If you want a new object with two keys, Object1 and Object2, you can do:
JSONObject Obj1 = (JSONObject) jso1.get("Object1");
JSONObject Obj2 = (JSONObject) jso2.get("Object2");
JSONObject combined = new JSONObject();
combined.put("Object1", Obj1);
combined.put("Object2", Obj2);
If you want to merge them, so e.g. a top level object has 5 keys (Stringkey1, ArrayKey, StringKey2, StringKey3, StringKey4), I think you have to do that manually:
JSONObject merged = new JSONObject(Obj1, JSONObject.getNames(Obj1));
for(String key : JSONObject.getNames(Obj2))
{
merged.put(key, Obj2.get(key));
}
This would be a lot easier if JSONObject implemented Map, and supported putAll.
In some cases you need a deep merge, i.e., merge the contents of fields with identical names (just like when copying folders in Windows). This function may be helpful:
/**
* Merge "source" into "target". If fields have equal name, merge them recursively.
* #return the merged object (target).
*/
public static JSONObject deepMerge(JSONObject source, JSONObject target) throws JSONException {
for (String key: JSONObject.getNames(source)) {
Object value = source.get(key);
if (!target.has(key)) {
// new value for "key":
target.put(key, value);
} else {
// existing value for "key" - recursively deep merge:
if (value instanceof JSONObject) {
JSONObject valueJson = (JSONObject)value;
deepMerge(valueJson, target.getJSONObject(key));
} else {
target.put(key, value);
}
}
}
return target;
}
/**
* demo program
*/
public static void main(String[] args) throws JSONException {
JSONObject a = new JSONObject("{offer: {issue1: value1}, accept: true}");
JSONObject b = new JSONObject("{offer: {issue2: value2}, reject: false}");
System.out.println(a+ " + " + b+" = "+JsonUtils.deepMerge(a,b));
// prints:
// {"accept":true,"offer":{"issue1":"value1"}} + {"reject":false,"offer":{"issue2":"value2"}} = {"reject":false,"accept":true,"offer":{"issue1":"value1","issue2":"value2"}}
}
You can create a new JSONObject like this:
JSONObject merged = new JSONObject();
JSONObject[] objs = new JSONObject[] { Obj1, Obj2 };
for (JSONObject obj : objs) {
Iterator it = obj.keys();
while (it.hasNext()) {
String key = (String)it.next();
merged.put(key, obj.get(key));
}
}
With this code, if you have any repeated keys between Obj1 and Obj2 the value in Obj2 will remain. If you want the values in Obj1 to be kept you should invert the order of the array in line 2.
This wrapper method will help :
private static JSONObject merge(JSONObject... jsonObjects) throws JSONException {
JSONObject jsonObject = new JSONObject();
for(JSONObject temp : jsonObjects){
Iterator<String> keys = temp.keys();
while(keys.hasNext()){
String key = keys.next();
jsonObject.put(key, temp.get(key));
}
}
return jsonObject;
}
Thanks to Erel. Here is a Gson version.
/**
* Merge "source" into "target". If fields have equal name, merge them recursively.
* Null values in source will remove the field from the target.
* Override target values with source values
* Keys not supplied in source will remain unchanged in target
*
* #return the merged object (target).
*/
public static JsonObject deepMerge(JsonObject source, JsonObject target) throws Exception {
for (Map.Entry<String,JsonElement> sourceEntry : source.entrySet()) {
String key = sourceEntry.getKey();
JsonElement value = sourceEntry.getValue();
if (!target.has(key)) {
//target does not have the same key, so perhaps it should be added to target
if (!value.isJsonNull()) //well, only add if the source value is not null
target.add(key, value);
} else {
if (!value.isJsonNull()) {
if (value.isJsonObject()) {
//source value is json object, start deep merge
deepMerge(value.getAsJsonObject(), target.get(key).getAsJsonObject());
} else {
target.add(key,value);
}
} else {
target.remove(key);
}
}
}
return target;
}
/**
* simple test
*/
public static void main(String[] args) throws Exception {
JsonParser parser = new JsonParser();
JsonObject a = null;
JsonObject b = null;
a = parser.parse("{offer: {issue1: null, issue2: null}, accept: true, reject: null}").getAsJsonObject();
b = parser.parse("{offer: {issue2: value2}, reject: false}").getAsJsonObject();
System.out.println(deepMerge(a,b));
// prints:
// {"offer":{},"accept":true}
a = parser.parse("{offer: {issue1: value1}, accept: true, reject: null}").getAsJsonObject();
b = parser.parse("{offer: {issue2: value2}, reject: false}").getAsJsonObject();
System.out.println(deepMerge(a,b));
// prints:
// {"offer":{"issue2":"value2","issue1":"value1"},"accept":true}
}
A ready method to merge any number of JSONObjects:
/**
* Merges given JSONObjects. Values for identical key names are merged
* if they are objects, otherwise replaced by the latest occurence.
*
* #param jsons JSONObjects to merge.
*
* #return Merged JSONObject.
*/
public static JSONObject merge(
JSONObject[] jsons) {
JSONObject merged = new JSONObject();
Object parameter;
for (JSONObject added : jsons) {
for (String key : toStringArrayList(added.names())) {
try {
parameter = added.get(key);
if (merged.has(key)) {
// Duplicate key found:
if (added.get(key) instanceof JSONObject) {
// Object - allowed to merge:
parameter =
merge(
new JSONObject[]{
(JSONObject) merged.get(key),
(JSONObject) added.get(key)});
}
}
// Add or update value on duplicate key:
merged.put(
key,
parameter);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
return merged;
}
/**
* Convert JSONArray to ArrayList<String>.
*
* #param jsonArray Source JSONArray.
*
* #return Target ArrayList<String>.
*/
public static ArrayList<String> toStringArrayList(JSONArray jsonArray) {
ArrayList<String> stringArray = new ArrayList<String>();
int arrayIndex;
for (
arrayIndex = 0;
arrayIndex < jsonArray.length();
arrayIndex++) {
try {
stringArray.add(
jsonArray.getString(arrayIndex));
} catch (JSONException e) {
e.printStackTrace();
}
}
return stringArray;
}
This is what I do
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
/**
* This class has all static functions to merge 2 objects into one
*/
public class MergeHelper {
private static ObjectMapper objectMapper = new ObjectMapper();
/**
* return a merge JsonNode, merge newJson into oldJson; override or insert
* fields from newJson into oldJson
*
* #param oldJson
* #param newJson
* #return
*/
public static JsonNode mergeJsonObject(JsonNode oldJson, JsonNode newJson) {
ObjectNode merged = objectMapper.createObjectNode();
merged.setAll((ObjectNode) oldJson);
merged.setAll((ObjectNode) newJson);
return merged;
}
}
For me that function worked:
private static JSONObject concatJSONS(JSONObject json, JSONObject obj) {
JSONObject result = new JSONObject();
for(Object key: json.keySet()) {
System.out.println("adding " + key + " to result json");
result.put(key, json.get(key));
}
for(Object key: obj.keySet()) {
System.out.println("adding " + key + " to result json");
result.put(key, obj.get(key));
}
return result;
}
(notice) - this implementation of concataion of json is for import
org.json.simple.JSONObject;
It's a while from the question but now JSONObject implements "toMap" method so you can try this way:
Map<String, Object> map = Obj1.toMap(); //making an HashMap from obj1
map.putAll(Obj2.toMap()); //moving all the stuff from obj2 to map
JSONObject combined = new JSONObject( map ); //new json from map
In addition to #erel's answer, I had to make this edit (I'm using org.json.simple) to the outer else for dealing with JSONArray's:
// existing value for "key" - recursively deep merge:
if (value instanceof JSONObject) {
JSONObject valueJson = (JSONObject)value;
deepMerge(valueJson, (JSONObject) target.get(key));
}
// insert each JSONArray's JSONObject in place
if (value instanceof JSONArray) {
((JSONArray) value).forEach(
jsonobj ->
((JSONArray) target.get(key)).add(jsonobj));
}
else {
target.put(key, value);
}
I used string to concatenate new object to an existing object.
private static void concatJSON() throws IOException, InterruptedException {
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader(new File(Main.class.getResource("/file/user.json").toURI())));
JSONObject jsonObj = (JSONObject) obj; //usernameJsonObj
String [] values = {"0.9" , Date.from(Calendar.getInstance().toInstant()).toLocaleString()},
innermost = {"Accomplished", "LatestDate"},
inner = {"Lesson1", "Lesson2", "Lesson3", "Lesson4"};
String in = "Jayvee Villa";
JSONObject jo1 = new JSONObject();
for (int i = 0; i < innermost.length; i++)
jo1.put(innermost[i], values[i]);
JSONObject jo2 = new JSONObject();
for (int i = 0; i < inner.length; i++)
jo2.put(inner[i], jo1);
JSONObject jo3 = new JSONObject();
jo3.put(in, jo2);
String merger = jsonObj.toString().substring(0, jsonObj.toString().length()-1) + "," +jo3.toString().substring(1);
System.out.println(merger);
FileWriter pr = new FileWriter(file);
pr.write(merger);
pr.flush();
pr.close();
}
Merging typed data structure trees is not trivial, you need to define the precedence, handle incompatible types, define how they will be casted and merged...
So in my opinion, you won't avoid
... pulling them all apart and individually adding in by puts`.
If your question is: Has someone done it for me yet?
Then I think you can have a look at this YAML merging library/tool I revived. (YAML is a superset of JSON), and the principles are applicable to both.
(However, this particular code returns YAML objects, not JSON. Feel free to extend the project and send a PR.)
Today, I was also struggling to merge JSON objects and came with following solution (uses Gson library).
private JsonObject mergeJsons(List<JsonObject> jsonObjs) {
JsonObject mergedJson = new JsonObject();
jsonObjs.forEach((JsonObject jsonObj) -> {
Set<Map.Entry<String, JsonElement>> entrySet = jsonObj.entrySet();
entrySet.forEach((next) -> {
mergedJson.add(next.getKey(), next.getValue());
});
});
return mergedJson;
}
Somebody already mentioned above. I'll just post a short version.
To merge two JSONObject json1 & json2 You could simply deal it with String like this:
String merged = json1.toString().substring(0, json1.length() - 1) + "," +
json2.toString().substring(1);
JSONObject mergedJson = new JSONObject(merged);
Of course, do not forget deal with JSONException. :)
Hope this could help you.
An improved version of merge on Gson's JsonObjects - can go any level of nested structure
/**
* Merge "source" into "target".
*
* <pre>
* An improved version of merge on Gson's JsonObjects - can go any level of nested structure:
* 1. merge root & nested attributes.
* 2. replace list of strings. For. eg.
* source -> "listOfStrings": ["A!"]
* dest -> "listOfStrings": ["A", "B"]
* merged -> "listOfStrings": ["A!", "B"]
* 3. can merge nested objects inside list. For. eg.
* source -> "listOfObjects": [{"key2": "B"}]
* dest -> "listOfObjects": [{"key1": "A"}]
* merged -> "listOfObjects": [{"key1": "A"}, {"key2": "B"}]
* </pre>
* #return the merged object (target).
*/
public static JsonObject deepMerge(JsonObject source, JsonObject target) {
for (String key: source.keySet()) {
JsonElement srcValue = source.get(key);
if (!target.has(key)) {
target.add(key, srcValue);
} else {
if (srcValue instanceof JsonArray) {
JsonArray srcArray = (JsonArray)srcValue;
JsonArray destArray = target.getAsJsonArray(key);
if (destArray == null || destArray.size() == 0) {
target.add(key, srcArray);
continue;
} else {
IntStream.range(0, srcArray.size()).forEach(index -> {
JsonElement srcElem = srcArray.get(index);
JsonElement destElem = null;
if (index < destArray.size()) {
destElem = destArray.get(index);
}
if (srcElem instanceof JsonObject) {
if (destElem == null) {
destElem = new JsonObject();
}
deepMerge((JsonObject) srcElem, (JsonObject) destElem);
} else {
destArray.set(index, srcElem);
}
});
}
} else if (srcValue instanceof JsonObject) {
JsonObject valueJson = (JsonObject)srcValue;
deepMerge(valueJson, target.getAsJsonObject(key));
} else {
target.add(key, srcValue);
}
}
}
return target;
}
Here is a version of https://stackoverflow.com/a/15070484/9897317 including JSONArrays :
/**
* Merge "source" into "target". If fields have equal name, merge them recursively.
* #return the merged object (target).
*/
public static JSONObject deepMerge(JSONObject source, JSONObject target) throws JSONException {
for (String key: JSONObject.getNames(source)) {
Object value = source.get(key);
if (value != null) {
if (!target.has(key)) {
// new value for "key":
target.put(key, value);
} else {
// existing value for "key" - recursively deep merge:
if (value instanceof JSONObject) {
JSONObject valueJson = (JSONObject)value;
deepMerge(valueJson, target.getJSONObject(key));
} else if (value instanceof JSONArray) {
JSONArray arr = (JSONArray) value;
JSONArray newArr = new JSONArray();
for (int i = 0; i < arr.length(); i++) {
newArr.put(deepMerge(arr.getJSONObject(i), target.getJSONArray(key).getJSONObject(i)));
}
target.put(key, newArr);
} else {
target.put(key, value);
}
}
}
}
return target;
}

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