I am trying to compare 2 JSON files, they have arrays with duplicated values.
My first JSON Object has an array like this:
"categories": [
"May",
"Apr",
"Mar"
]
My second JSON object has an array like this:
"categories": [
"May",
"May",
"Apr",
"Apr",
"Mar",
"Mar"
]
I am comparing the JSON using flat maps that can be found in this link comparing JSONs using guava
Here is part of my code:
private String smartJSONsCompare(JSONObject leftJson, JSONObject rightJson) {
String result = "</br>";
Gson gson = new Gson();
Type type = new TypeToken<Map<String, Object>>(){}.getType();
Map<String, Object> leftMap = gson.fromJson(leftJson.toString(), type);
Map<String, Object> rightMap = gson.fromJson(rightJson.toString(), type);
Map<String, Object> leftFlatMap = FlatMapUtil.flatten(leftMap);
Map<String, Object> rightFlatMap = FlatMapUtil.flatten(rightMap);
MapDifference<String, Object> difference = Maps.difference(leftFlatMap, rightFlatMap);
StringBuilder SB = new StringBuilder("</br>");
SB.append("Entries only on LEFT: </br>");
difference.entriesOnlyOnLeft().forEach((key, value) -> SB.append(key + ": " + value + "</br>"));
SB.append("Entries only on RIGHT: </br>");
difference.entriesOnlyOnRight().forEach((key, value) -> SB.append(key + ": " + value + "</br>"));
SB.append("Entries full difference : </br>");
difference.entriesDiffering().forEach((key, value) -> SB.append(key + ": " + value + "</br>"));
result = SB.toString();
return result;
}
I wish to be able to present the difference in a more "smart" way. In other words: showing all the objects / arrays in the JONSs that don't match. What is missing or what was added to the compared JSON.
For the "categories" array my code returns a message that their is a mismatch, but doesn't state the difference in an elegant way.
What can I do?
I have change a bit in your solution to get the wanted result.
I would do my difference check in List, therefore I will create method to change JSON to list of strings based on your code:
private static List<String> jsonToList(String json){
List<String> list = new ArrayList<>();
Gson gson = new Gson();
Type type = new TypeToken<Map<String, Object>>(){}.getType();
Map<String, Object> jsonMap = gson.fromJson(json, type);
Map<String, Object> flatten = FlatMapUtil.flatten(jsonMap);
flatten.forEach((k, v) -> list.add(v.toString()));
return list;
}
Update
When I answered the question I did things a bit fast, the jsonToList was based on your code. As it is right now it is over complicated to what you are asking for. I have therefore made much lighter version using the following method in stead:
private static List<String> jsonToList(String json) {
JSONObject response = new JSONObject(json);
List<String> list = new ArrayList<>();
JSONArray jsonArray = response.getJSONArray("categories");
if (jsonArray != null) {
for (int i = 0; i < jsonArray.length(); i++) {
list.add(jsonArray.get(i).toString());
}
}
return list;
}
That said, now you have two choices and it is up to you to find out which one fits best to your needs and take it from here.
End of Update
for this example I have made 3 test examples
String main = "{\"categories\":[\"May\",\"Apr\",\"Mar\"]}";
String json1 = "{\"categories\":[\"May\",\"May\",\"Apr\",\"Apr\",\"Mar\",\"Mar\"]}";
String json2 = "{\"categories\":[\"May\",\"Apr\",\"Apr\",\"Mar\",\"Mar\",\"Mar\"]}";
String json3 = "{\"categories\":[\"May\",\"Apr\",\"Mar\",\"Mar\"]}";
in my second step I will create a
List<String> mainList = jsonToList(main);
List<String> list1 = jsonToList(json1);
so far so good. Now I make a method to take the extra difference of the 2 list, that mean as you requested in your comments, we take only all values that are duplicated more than once and return them in list. In this method I used hashmap only count duplicates and than take the all that is repeated more than 1 time:
private static List<String> diffList(List<String> mainList, List<String> secondList){
List<String> list = new ArrayList<String>();
Map<String, Integer> wordCount = new HashMap<>();
for(String word: secondList) {
if(mainList.contains(word)) {
Integer count = wordCount.get(word);
wordCount.put(word, (count == null) ? 1 : count + 1);
if(wordCount.get(word) > 1){
list.add(word);
}
}
}
return list;
}
Finally I would test all cases, for instance for list1:
List<String> diff1 = diffList(mainList, list1);
for (String s : diff1) {
System.out.println(s);
}
The output will be
May
Apr
Mar
for list2
Apr
Mar
Mar
And for list3
Mar
Now I will separate view method from the your method and create some thing like, just to make my code more clear and easy to work with:
private static String viewResult(List<String> list1, List<String> list2, List<String> duplicate){
String result;
StringBuilder SB = new StringBuilder("</br>");
SB.append("Entries only on LEFT: </br>");
list1.forEach(e -> SB.append(e + "</br>"));
SB.append("Entries only on RIGHT: </br>");
list2.forEach(e -> SB.append(e + "</br>"));
SB.append("Entries full difference : </br>");
duplicate.forEach(e -> SB.append(e + "</br>"));
result = SB.toString();
return result;
}
So if we put all this code together I will be some thing like this, and the following code is to demonstrate how things works, but from here you can take it to the next level in your code:
public static void main(String[] args) {
String main = "{\"categories\":[\"May\",\"Apr\",\"Mar\"]}";
String json1 = "{\"categories\":[\"May\",\"May\",\"Apr\",\"Apr\",\"Mar\",\"Mar\"]}";
String json2 = "{\"categories\":[\"May\",\"Apr\",\"Apr\",\"Mar\",\"Mar\",\"Mar\"]}";
String json3 = "{\"categories\":[\"May\",\"Apr\",\"Mar\",\"Mar\"]}";
List<String> mainList = jsonToList(main);
List<String> list1 = jsonToList(json1);
List<String> diff1 = diffList(mainList, list1);
for (String s : diff1) {
System.out.println(s);
}
String view = viewResult(mainList, list1, diff1);
}
private static List<String> jsonToList(String json){
List<String> list = new ArrayList<String>();
Gson gson = new Gson();
Type type = new TypeToken<Map<String, Object>>(){}.getType();
Map<String, Object> jsonMap = gson.fromJson(json, type);
Map<String, Object> flatten = FlatMapUtil.flatten(jsonMap);
flatten.forEach((k, v) -> list.add(v.toString()));
return list;
}
private static List<String> diffList(List<String> mainList, List<String> secondList){
List<String> list = new ArrayList<String>();
Map<String, Integer> wordCount = new HashMap<>();
for(String word: secondList) {
if(mainList.contains(word)) {
Integer count = wordCount.get(word);
wordCount.put(word, (count == null) ? 1 : count + 1);
if(wordCount.get(word) > 1){
list.add(word);
}
}
}
return list;
}
private static String viewResult(List<String> list1, List<String> list2, List<String> duplicate){
String result;
StringBuilder SB = new StringBuilder("</br>");
SB.append("Entries only on LEFT: </br>");
list1.forEach(e -> SB.append(e + "</br>"));
SB.append("Entries only on RIGHT: </br>");
list2.forEach(e -> SB.append(e + "</br>"));
SB.append("Entries full difference : </br>");
duplicate.forEach(e -> SB.append(e + "</br>"));
result = SB.toString();
return result;
}
If you want something more generic with a good diff you could utilize AssertJ here.
Its usually used for Testing, but the diff looks really good and you can also use it in normal code.
Example:
Expecting:
<["Mai", "Apr", "Mar"]>
to contain exactly in any order:
<["May", "Apr", "Mar", "Mar"]>
elements not found:
<["May", "Mar"]>
and elements not expected:
<["Mai"]>
Can be created by:
[...]
import org.assertj.core.api.Assertions;
public class JsonTest {
final static String arr = " [\n"+
" \"Mai\",\n"+
" \"Apr\",\n"+
" \"Mar\"\n"+
" ]";
final static String arr2 = " [\n"+
" \"May\",\n"+
" \"Apr\",\n"+
" \"Mar\",\n"+
" \"Mar\"\n"+
" ]";
public static void main(String[] args){
System.out.println(smartJSONsCompare(arr,arr2));
}
private static String smartJSONsCompare(String leftJson, String rightJson) {
Gson gson = new Gson();
Type type = new TypeToken<List<String>>(){}.getType();
List<String> left = gson.fromJson(leftJson, type);
List<String> right = gson.fromJson(rightJson, type);
try{
Assertions.assertThat(left).containsExactlyInAnyOrderElementsOf(right);
}catch(AssertionError ae){
return ae.getMessage();
}
return "Matched";
}
}
I added the dependencies in gradle with:
dependencies {
compile("org.assertj:assertj-core:3.11.1")
}
If you want to create a patch between your two JSON Objects have a look at json-patch.
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.fge.jsonpatch.diff.JsonDiff;
import java.io.IOException;
public class JsonPatchTest {
public static void main(String[] args) throws IOException {
String jsonFirst = "{\"categories\":[\"May\",\"Apr\",\"Mar\"]}";
String jsonSecond = "{\"categories\":[\"May\",\"May\",\"Apr\",\"Apr\",\"Mar\",\"Mar\"]}";
ObjectMapper mapper = new ObjectMapper();
JsonNode jsonNodeFirst = mapper.readTree(jsonFirst);
JsonNode jsonNodeSecond = mapper.readTree(jsonSecond);
JsonNode patchNode = JsonDiff.asJson(jsonNodeFirst, jsonNodeSecond);
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(patchNode));
}
}
Would produce the following output for your scenario:
[ {
"op" : "replace",
"path" : "/categories/1",
"value" : "May"
}, {
"op" : "replace",
"path" : "/categories/2",
"value" : "Apr"
}, {
"op" : "add",
"path" : "/categories/-",
"value" : "Apr"
}, {
"op" : "add",
"path" : "/categories/-",
"value" : "Mar"
}, {
"op" : "add",
"path" : "/categories/-",
"value" : "Mar"
} ]
I believe you should handle json arrays on your own in order to present their difference in a more "smart" way. Here is a library which contains CollectionUtils class with disjunction method.
MapDifference<String, Object> difference = Maps.difference(leftMap, rightMap);
difference.entriesDiffering().forEach((key, value) -> {
Object left = value.leftValue();
Object right = value.rightValue();
if (left instanceof Iterable && right instanceof Iterable) {
Collection<?> diff = CollectionUtils.disjunction((Iterable<?>) right, (Iterable<?>) left);
System.out.println(key + " -> " + diff);
}
...
});
This code work for me (2 years ago) on production.
public class App {
private final Gson GSON = new GsonBuilder().create();
public boolean isDifference(final String path, Map<String, Object> oldData, Map<String, Object> newData) {
MapDifference<String, Object> difference = Maps.difference(oldData, newData);
difference.entriesOnlyOnLeft().forEach((key, value) -> {
publishChange(Action.REMOVE, path, key, value);
});
difference.entriesOnlyOnRight().forEach((key, value) -> {
publishChange(Action.ADD, path, key, value);
});
difference.entriesDiffering().forEach((key, value) -> {
if (value.rightValue() instanceof Map && value.leftValue() instanceof Map) {
if (!path.isEmpty()) {
key = path.concat("-").concat(key);
}
isDifference(key, (Map) value.leftValue(), (Map) value.rightValue());
} else {
publishChange(Action.MODIFY, path, key, value);
}
});
return !difference.areEqual();
}
public void publishChange(Action action, String path, String key, Object value) {
if (value instanceof MapDifference.ValueDifference) {
value = ((MapDifference.ValueDifference) value).rightValue();
}
JsonElement jsonValue = GSON.toJsonTree(value);
String event = createEvent(action, path, key, jsonValue);
System.out.println("Differrence: " + event);
}
public String createEvent(Action action, String paths, String key, JsonElement value) {
JsonObject root = new JsonObject();
JsonArray arrPaths = new JsonArray();
for (String path : paths.split("-")) {
arrPaths.add(path);
}
root.addProperty("action", action.toString());
root.add("paths", arrPaths);
JsonObject data = new JsonObject();
data.addProperty("key", key);
data.add("value", value);
root.add("data", data);
return root.toString();
}
public static enum Action {
ADD, REMOVE, MODIFY
}}
Test/ Example:
public class AppTest {
#Test
public void testAppHasAGreeting() {
App classUnderTest = new App();
Gson gson = new GsonBuilder()
.setPrettyPrinting()
.create();
// JsonOld: {"a":1,"b":1,"c":true,"array":[1,2,3],"object":{"arrayKey":["a","b","c","d"]}}
String jsonOld = "{\"a\":1,\"b\":1,\"c\":true,\"array\":[1,2,3],\"object\":{\"arrayKey\":[\"a\",\"b\",\"c\",\"d\"]}}";
// JsonNew: {"a":2,"b":1,"array":[1,2,3,2],"another":{"d":false,"e":["a","b","c"]},"object":{"booleanKey":true,"arrayKey":["a","b","c"]}}
String jsonNew = "{\"a\":2,\"b\":1,\"array\":[1,2,3,2],\"another\":{\"d\":false,\"e\":[\"a\",\"b\",\"c\"]},\"object\":{\"booleanKey\":true,\"arrayKey\":[\"a\",\"b\",\"c\"]}}";
Type mapType = new TypeToken<Map<String, Object>>() {
}.getType();
Map<String, Object> jsonOldAsMap = gson.fromJson(jsonOld, mapType);
Map<String, Object> jsonNewAsMap = gson.fromJson(jsonNew, mapType);
System.out.println("Old Json: " + gson.toJson(jsonOldAsMap));
System.out.println("New Json: " + gson.toJson(jsonNewAsMap));
System.out.println("========== Result ==========");
// When
boolean diff = classUnderTest.isDifference("", jsonOldAsMap, jsonNewAsMap);
// Then
assertTrue(diff);
}}
The result will print like this:
Differrence: {"action":"REMOVE","paths":[""],"data":{"key":"c","value":true}}
Differrence: {"action":"ADD","paths":[""],"data":{"key":"another","value":{"d":false,"e":["a","b","c"]}}}
Differrence: {"action":"MODIFY","paths":[""],"data":{"key":"a","value":2.0}}
Differrence: {"action":"MODIFY","paths":[""],"data":{"key":"array","value":[1.0,2.0,3.0,2.0]}}
Differrence: {"action":"ADD","paths":["object"],"data":{"key":"booleanKey","value":true}}
Differrence: {"action":"MODIFY","paths":["object"],"data":{"key":"arrayKey","value":["a","b","c"]}}
The code available here: https://github.com/liemle3893/compare-json
In Java, we've got some code that takes a complex java object and serializes it to json. It then writes that json directly to the markup of a page, in a script tag, assigning it to a variable.
// Get object as JSON using Jackson
ObjectWriter jsonWriter = new ObjectMapper().writer().withDefaultPrettyPrinter();
String json = jsonWriter.writeValueAsString(complexObject);
// Write JSON out to page, and assign it to a javascript variable.
Writer out = environment.getOut();
out.write("var data = " + json);
The complex object can have end user content in it, which could open us up to XSS attacks.
How can I get a json version of the complex java object that has each json attribute HTML escaped, to protect against XSS injection?
I've read the OWASP XSS Guide and the best I've come up with so far is this, which HTML escapes the entire JSON string, then undoes the quotes, so it can be assigned to a variable in javascript. I'm sure there are better ways to do this, but this seems to work. Any suggestions?
private String objectToHtmlEscapedJson(Object value) {
try {
String result = jsonWriter.writeValueAsString(value);
result = StringEscapeUtils.escapeHtml(result);
result = result.replace(""", "\"");
return result;
} catch (JsonProcessingException e) {
return "null";
}
}
A possible approach could be to iterate over the object entries and individually escape each key and value once the node is constructed by your chosen library.
Following my comment above, I've implemented a simple recursive solution using both Jackson (from your question) and GSON, a different library where objects are slightly easier to construct and the code is more readable. The escaping mechanism used is the OWASP Java Encoder:
Jackson
private static JsonNode clean(JsonNode node) {
if(node.isValueNode()) { // Base case - we have a Number, Boolean or String
if(JsonNodeType.STRING == node.getNodeType()) {
// Escape all String values
return JsonNodeFactory.instance.textNode(Encode.forHtml(node.asText()));
} else {
return node;
}
} else { // Recursive case - iterate over JSON object entries
ObjectNode clean = JsonNodeFactory.instance.objectNode();
for (Iterator<Map.Entry<String, JsonNode>> it = node.fields(); it.hasNext(); ) {
Map.Entry<String, JsonNode> entry = it.next();
// Encode the key right away and encode the value recursively
clean.set(Encode.forHtml(entry.getKey()), clean(entry.getValue()));
}
return clean;
}
}
GSON
private static JsonElement clean(JsonElement elem) {
if (elem.isJsonPrimitive()) { // Base case - we have a Number, Boolean or String
JsonPrimitive primitive = elem.getAsJsonPrimitive();
if(primitive.isString()) {
// Escape all String values
return new JsonPrimitive(Encode.forHtml(primitive.getAsString()));
} else {
return primitive;
}
} else if (elem.isJsonArray()) { // We have an array - GSON requires handling this separately
JsonArray cleanArray = new JsonArray();
for(JsonElement arrayElement: elem.getAsJsonArray()) {
cleanArray.add(clean(arrayElement));
}
return cleanArray;
} else { // Recursive case - iterate over JSON object entries
JsonObject obj = elem.getAsJsonObject();
JsonObject clean = new JsonObject();
for(Map.Entry<String, JsonElement> entry : obj.entrySet()) {
// Encode the key right away and encode the value recursively
clean.add(Encode.forHtml(entry.getKey()), clean(entry.getValue()));
}
return clean;
}
}
Sample input (both libraries):
{
"nested": {
"<html>": "<script>(function(){alert('xss1')})();</script>"
},
"xss": "<script>(function(){alert('xss2')})();</script>"
}
Sample output (both libraries):
{
"nested": {
"<html>": "<script>(function(){alert('xss1')})();</script>"
},
"xss": "<script>(function(){alert('xss2')})();</script>"
}
I think Paul Benn's answer is the best approach overall, but if you don't want to iterate over the json nodes, you could consider using Encode.forHtmlContent, which doesn't escape quotes. I feel this is probably safe as I can't think of how introducing an additional quote into a quoted string could cause an exploit. I'll leave it to the reader to review the docs and decide for themselves!
ivy.xml
<dependency org="org.owasp.encoder" name="encoder" rev="1.2.1"/>
and some code to do the html encoding
private String objectToJson(Object value)
{
String result;
try
{
result = jsonWriter.writeValueAsString(value);
return Encode.forHtmlContent(result);
}
catch (JsonProcessingException e)
{
return "null";
}
}
Updating Paul Benn's answer of the Gson version to include json value being an array
private static JsonElement clean(JsonElement elem) {
if(elem.isJsonPrimitive()) { // Base case - we have a Number, Boolean or String
JsonPrimitive primitive = elem.getAsJsonPrimitive();
if(primitive.isString()) {
// Escape all String values
return new JsonPrimitive(Encode.forHtml(primitive.getAsString()));
} else {
return primitive;
}
} else if( elem.isJsonArray() ) { // If the object is an array "cars": ["toyota", "nissan", "bmw"]
JsonArray jsonA = elem.getAsJsonArray();
JsonArray cleanedNewArray = new JsonArray();
for(JsonElement jsonAE: jsonA) {
cleanedNewArray.add(clean(jsonAE));
}
return cleanedNewArray;
} else { // Recursive case - iterate over JSON object entries
JsonObject obj = elem.getAsJsonObject();
JsonObject clean = new JsonObject();
for(Map.Entry<String, JsonElement> entry : obj.entrySet()) {
// Encode the key right away and encode the value recursively
clean.add(Encode.forHtml(entry.getKey()), clean(entry.getValue()));
}
return clean;
}
}
Adding a version of JKRo using Jackson with Esapi.
private JsonNode clean(JsonNode node, ObjectMapper mapper) {
if(node.isValueNode()) { // Base case - we have a Number, Boolean or String
if(JsonNodeType.STRING == node.getNodeType()) {
// Escape all String values
return JsonNodeFactory.instance.textNode(ESAPI.encoder().encodeForHTML(node.asText()));
} else {
return node;
}
} else if(node.isArray()) { // If the object is an array "cars": ["toyota", "nissan", "bmw"]
ArrayNode cleanedNewArray = mapper.createArrayNode();
for (final JsonNode objNode : node) {
cleanedNewArray.add(clean(objNode, mapper));
}
return cleanedNewArray;
} else { // Recursive case - iterate over JSON object entries
ObjectNode clean = JsonNodeFactory.instance.objectNode();
for (Iterator<Map.Entry<String, JsonNode>> it = node.fields(); it.hasNext(); ) {
Map.Entry<String, JsonNode> entry = it.next();
// Encode the key right away and encode the value recursively
clean.set(ESAPI.encoder().encodeForHTML(entry.getKey()), clean(entry.getValue(), mapper));
}
return clean;
}
}
Request Body:
{
"param1": "<input class='btn btn-default' value='0' placeholder='Ingrese sus datos'></input>",
"param3": [
{
"nombre" : "<input class='btn btn-default' value='0' placeholder='Ingrese sus datos'></input>",
"apellido": "<script>alert('Hola mundex');</script>"
},
{
"param4": {
"nombre" : "<input class='btn btn-default' value='0' placeholder='Ingrese sus datos'></input>",
"apellido": "<script>alert('Hola mundex');</script>"
}
}],
"param2": "alert('Hola')"
}
Response Body:
{
"param1": "<input class='btn btn-default' value='0' placeholder='Ingrese sus datos'></input>",
"param3": [
{
"nombre": "<input class='btn btn-default' value='0' placeholder='Ingrese sus datos'></input>",
"apellido": "<script>alert('Hola mundex');</script>"
},
{
"param4": {
"nombre": "<input class='btn btn-default' value='0' placeholder='Ingrese sus datos'></input>",
"apellido": "<script>alert('Hola mundex');</script>"
}
}
],
"param2": "alert('Hola')"
}
I have a json string which I need to validate and find any other keys other than in a list is there in the json string. The sample json string is
{
"required" : true,
"requiredMsg" : "Title needed",
"choices" : [ "a", "b", "c", "d" ],
"choiceSettings" : {
"a" : {
"exc" : true
},
"b" : { },
"c" : { },
"d" : {
"textbox" : {
"required" : true
}
}
},
"Settings" : {
"type" : "none"
}
}
To allow only predifined keys is exsist in the json string I want to get all the keys in the json string. How can I obtain all the keys in the json string. I am using jsonNode. My code till now is
JsonNode rootNode = mapper.readTree(option);
JsonNode reqiredMessage = rootNode.path("reqiredMessage");
System.out.println("msg : "+ reqiredMessage.asText());
JsonNode drNode = rootNode.path("choices");
Iterator<JsonNode> itr = drNode.iterator();
System.out.println("\nchoices:");
while (itr.hasNext()) {
JsonNode temp = itr.next();
System.out.println(temp.asText());
}
How to get all the keys from the json string using JsonNode
forEach will iterate over children of a JsonNode (converted to String when printed) and fieldNames() gets an Iterator<String> over keys. Here are some examples for printing elements of the example JSON:
JsonNode rootNode = mapper.readTree(option);
System.out.println("\nchoices:");
rootNode.path("choices").forEach(System.out::println);
System.out.println("\nAllKeys:");
rootNode.fieldNames().forEachRemaining(System.out::println);
System.out.println("\nChoiceSettings:");
rootNode.path("choiceSettings").fieldNames().forEachRemaining(System.out::println);
You'll probably need fields() at some point that returns an Iterator<Entry<String, JsonNode>> so you can iterate over key, value pairs.
This should do it.
Map<String, Object> treeMap = mapper.readValue(json, Map.class);
List<String> keys = Lists.newArrayList();
List<String> result = findKeys(treeMap, keys);
System.out.println(result);
private List<String> findKeys(Map<String, Object> treeMap , List<String> keys) {
treeMap.forEach((key, value) -> {
if (value instanceof LinkedHashMap) {
Map<String, Object> map = (LinkedHashMap) value;
findKeys(map, keys);
}
keys.add(key);
});
return keys;
}
This will print out result as
[required, requiredMsg, choices, exc, a, b, c, required, textbox, d, choiceSettings, type, Settings]
The accepted answer works out great but issues a warning, "Type safety: The expression of type Map needs unchecked conversion to conform to Map <String, Object>"
This answer led me to change that line to the following to eliminate the warning:
Map<String, Object> treeMap = mapper.readValue(json, new TypeReference<Map<String, Object>>() {});
List in the json was not supported in the accepted solution. Here is what I propose:
public List<String> getAllNodeKeys(String json) throws JsonProcessingException {
Map<String, Object> treeMap = objectMapper.readValue(json, new TypeReference<>() {
});
return findKeys(treeMap, new ArrayList<>());
}
private List<String> findKeys(Map<String, Object> treeMap, List<String> keys) {
treeMap.forEach((key, value) -> {
if (value instanceof LinkedHashMap) {
LinkedHashMap map = (LinkedHashMap) value;
findKeys(map, keys);
} else if (value instanceof List) {
ArrayList list = (ArrayList) value;
list.forEach(map -> findKeys((LinkedHashMap) map, keys));
}
keys.add(key);
});
return keys;
}
I have json structure like this,how I parse the json with help of Gson.I need to store the key values in json object,I tried many example related to dynamic array but dynamic json array without square brace I cannot parse using Gson.Any Solutions or need to do Manual Json Parse?If any one feel duplicate comment the answer below.
{ "Result":[[
"Title",
{
"0": 1323,
"1": 3358,
"2": 2123,
"3": 8536,
"4": 1399,
"5": 9303,
"7": 9732,
"8": 3433,
"9": 1383
}
],[
"Title",
{
"0": 1323,
"1": 3358,
"2": 2123,
"3": 8536,
}
]]}
To start, your JSON causes an exception to be thrown because it is invalid - You have an extra comma at the end of the last value in the second example. "3": 8536, should be "3": 8536.
After fixing that, this should be a simple task provided you define your objects correctly. Here is what I came up with:
public class Results {
#SerializedName("Result")
List<Result> results;
}
public class Result {
String title;
Map<String, Integer> results;
}
From there, the Result class needs to be deserialized in a special fashion, since the fields in the Result class do not directly map to entries in the JSON. Instead, we need to pull off the first and second elements of the JsonArray that is contained within each Result, and parse it accordingly. That looks like this:
public class ResultDeserializer implements JsonDeserializer<Result> {
#Override
public Result deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
JsonArray array = json.getAsJsonArray();
Result result = new Result();
result.title = array.get(0).getAsString();
result.results = new LinkedHashMap<String, Integer>();
for(Entry<String, JsonElement> entry : array.get(1).getAsJsonObject().entrySet()) {
result.results.put(entry.getKey(), entry.getValue().getAsInt());
}
return result;
}
}
Note that my example omits error checking. Finally, register this deserializer, and you should be all set:
Gson gson = new GsonBuilder().registerTypeAdapter(Result.class, new ResultDeserializer()).create();
Results results = gson.fromJson(json, Results.class);
for(Result r : results.results) {
System.out.println("Title = " + r.title);
for(Entry<String, Integer> entry : r.results.entrySet()) {
System.out.println("\t " + entry.getKey() + " -> " + entry.getValue());
}
}
This prints:
Title = Title
0 -> 1323
1 -> 3358
2 -> 2123
3 -> 8536
4 -> 1399
5 -> 9303
7 -> 9732
8 -> 3433
9 -> 1383
Title = Title
0 -> 1323
1 -> 3358
2 -> 2123
3 -> 8536
I'll leave it to the OP to implement the reverse, that is a serializer for Result to produce the same results.
Found simple way to parse above json using Nested Map in Gson
Result.java
public class Result {
#SerializedName("formatted_facet_fields")
Map<String,Map<String,String>> formatted_facet_fields;
}
in response receiving side
Gson gson=new Gson();
Result result = gson.fromJson(json_response, Result.class);
Yes, You can parse nested json object.
if (!exists) {
keys = json.keys();
while (keys.hasNext()) {
nextKeys = (String) keys.next();
try {
if (json.get(nextKeys) instanceof JSONObject) {
if (exists == false) {
getKey(json.getJSONObject(nextKeys), key);
}
} else if (json.get(nextKeys) instanceof JSONArray) {
JSONArray jsonarray = json.getJSONArray(nextKeys);
for (int i = 0; i < jsonarray.length(); i++) {
String jsonarrayString = jsonarray.get(i).toString();
JSONObject innerJSOn = new JSONObject(jsonarrayString);
if (exists == false) {
getKey(innerJSOn, key);
}
}
}
} catch (Exception e) {
// TODO: handle exception
}
}
For complete understanding checkout below: Code Explanation : https://www.youtube.com/watch?v=ZjZqLUGCWxo
I am using this code below to merge JSON data into a template, to get HTML:
Template:
String schema = "<h1>{{header}}</h1>"
+ "{{#bug}}{{/bug}}"
+ "{{#items}}"
+ "{{#first}}"
+ "<li><strong>{{title}}</strong>
+ </li>"
+ "{{/first}}"
+ "{{#link}}"
+ "<li><a href=\"{{url}}\">{{name}}
+ </a></li>"
+ "{{/link}}"
+ "{{/items}}"
+ "{{#empty}}"
+ "<p>The list is empty.</p>"
+ "{{/empty}}";
JSON object:
try {
String template = "{\"header\": \"Colors\", "
+ "\"items\": [ "
+ "{\"name\": \"red\", \"first\": true, \"url\": \"#Red\"}, "
+ "{\"name\": \"green\", \"link\": true, \"url\": \"#Green\"}, "
+ "{\"name\": \"blue\", \"link\": true, \"url\": \"#Blue\"}"
+ " ], \"empty\": false }";
JSONObject jsonWithArrayInIt = new JSONObject(template);
JSONArray items = jsonWithArrayInIt.getJSONArray("items");
Map<String,String> ctx = new HashMap<String,String>();
ctx.put("foo.bar", "baz");
Mustache.compiler().standardsMode(true).compile("{{foo.bar}}").execute(ctx);
System.out.println("itemised: " + items.toString());
} catch(JSONException je) {
//Error while creating JSON.
}
I pass a map of data to get Mustache to work. The method looks like this:
public static Map<String, Object> toMap(JSONObject object)
throws JSONException {
Map<String, Object> map = new HashMap();
Iterator keys = object.keys();
while (keys.hasNext()) {
String key = (String) keys.next();
map.put(key, fromJson(object.get(key)));
}
return map;
}
I am following a Mustache Guide to get the Mustache autoformation. But I don't know how to get the result I am expecting. The output should be as follows:
<h1>Colors</h1>
<li><strong></strong></li>
<li>green</li>
<li>blue</li>
I think you need to rethink your Mustache template slightly. The jMustache library (which I assume you are using) seems to always treat {{# entities as lists and iterate their contents, regardless of the data type passed in.
Something like this should work:
<h1>{{header}}</h1>
{{#items}}
<li>
{{#url}}<a href="{{.}}">{{/url}}
{{^url}}<strong>{{/url}}
{{caption}}
{{#url}}</a>{{/url}}
{{^url}}</strong>{{/url}}
</li>
{{/items}}
{{^items}}
<p>The list is empty.</p>
{{/items}}
This will produce an HMTL anchor only if a "link" value is provided, thus avoiding the jMustache if condition issue. So the JSON model would look something like this:
{
"header": "Colors",
"items": [
{"caption": "title"},
{"caption": "red", "url": "#Red"},
{"caption": "green", "url": "#Green"},
{"caption": "blue", "url": "#Blue"}
]
}
Finally, you will need to convert your JSON to something jMustache understands. I've never seen or heard of the "HTTPFunctions" class in any library I've used, but I've done some similar mapping using Gson in the past. Note that this is a very simple implementation and you may need to extend it to fit your needs:
private Map<String, Object> getModelFromJson(JSONObject json) throws JSONException {
Map<String,Object> out = new HashMap<String,Object>();
Iterator it = json.keys();
while (it.hasNext()) {
String key = (String)it.next();
if (json.get(key) instanceof JSONArray) {
// Copy an array
JSONArray arrayIn = json.getJSONArray(key);
List<Object> arrayOut = new ArrayList<Object>();
for (int i = 0; i < arrayIn.length(); i++) {
JSONObject item = (JSONObject)arrayIn.get(i);
Map<String, Object> items = getModelFromJson(item);
arrayOut.add(items);
}
out.put(key, arrayOut);
}
else {
// Copy a primitive string
out.put(key, json.getString(key));
}
}
return out;
}
This basic JUnit test demonstrates the theory: http://www.pasteshare.co.uk/p/841/
Just use
Map<String, Object> s = HTTPFunctions.toMap(new JSONObject(template));