I managed to update a json object using a jsonPath with this code
JSONObject json = new JSONObject("{\"data\":[{\"city\":\"New York\",\"name\":\"John\",\"age\":31},{\"city\":\"Paris\",\"name\":\"Jack\",\"age\":12}]}");
DocumentContext doc = JsonPath.parse(json.toString())
.set("$..name","newName");
System.out.println("doc.jsonString() = " + doc.jsonString());
outputs:
doc.jsonString() = {"data":[{"city":"New York","name":"newName","age":31},{"city":"Paris","name":"newName","age":12}]}
Now I would like to update the value depending on the old value (by applying a function on the old value)
Something like
DocumentContext doc = JsonPath.parse(json.toString())
.set("$..name",upper(oldValue))
.set("$..age", oldValue+10);
That would result in the following json
doc.jsonString() = doc.jsonString() = {"data":[{"city":"New York","name":"JOHN","age":41},{"city":"Paris","name":"JACK","age":22}]}
Does someone know how I can manage to reference the old value like that ?
Regards,
You can use the map function of the DocumentContext class like the example below:
DocumentContext json = JsonPath.using(configuration).parse(jsonStr);
DocumentContext result = json.map("$..name", (currentValue, configuration) -> {
return currentValue.toString().toUpperCase();
});
System.out.println(result.jsonString());
That example change the value to uppercase.
Try to check about it in the Jsonpath DocumentContext class documentation.
You can use parse and set functions of JsonPath.
example:
public static String replaceOldValueVithNewValueforGivenPath(String jsonBody, String path, String newValue)
{
// validateJsonInput(jsonBody);
try {
return JsonPath.parse(jsonBody).set(path,newValue).jsonString();
} catch (PathNotFoundException var3) {
throw new RuntimeException("No results for path: " + path);
}
}
Related
ResponseEntity<String> respEntity = null;
try {
respEntity = getConfiguredRestTemplate().exchange(uri.toString()
, HttpMethod.GET
, entity
, new ParameterizedTypeReference<String>() {
});
log.debug("URL to retrieve a document : {}", respEntity.getBody());
}
The respEntity.getBody() returns {"url":"https://aps-fst"}
I want to send only the value - https://aps-fst as parameter to a function to download the content in the URL. How to extract only the URL value and pass it as parameter of type URL / String ?
You can use ObjectMapper from jackson and have the response body transformed into a map from which you can take the url value. You can find an example here.
String jsonString = respEntity.getBody();
JSONObject obj = new JSONObject(jsonString);
String s3urlvalue = obj.getString("url");
log.debug("S3 URL to retrieve a document : {} ", s3urlvalue);
I am able to get value with above code
I need to write a code which would convert JSON file to CSV. The problem is in a format that the CSV file should look like.
Input json:
{
"strings":{
"1level1":{
"1level2":{
"1label1":"1value1",
"1label2":"1value2"
}
},
"2level1":{
"2level2":{
"2level3":{
"2label1":"2value1"
},
"2label2":"2value2"
}
}
}
}
And this is expected csv file for this json:
Keys,Default
1level1.1level2.1label1,1value1
1level1.1level2.1label2,1value2
2level1.2level2.2level3.2label1,2value1
2level1.2level2.2label2,2value2
I was trying to go through JSON file using recursion but this didn't work for me because of rewriting JSON object on each iteration and code was working only till the first value. Are there any suggestions about how can it be done?
Note: have tried to use different JSON libraries, so for now can be used any of them
UPDATE #1:
Non-working code example I was trying to use to go through JSON tree:
public static void jsonToCsv() throws JSONException {
InputStream is = MainClass.class.getResourceAsStream("/fromJson.json");
JSONTokener jsonTokener = new JSONTokener(is);
JSONObject jsonObject = new JSONObject(jsonTokener);
stepInto(jsonObject);
}
private static void stepInto(JSONObject jsonObject) {
JSONObject object = jsonObject;
try {
Set < String > keySet = object.keySet();
for (String key: keySet) {
object = object.getJSONObject(key);
stepInto(object);
}
} catch (JSONException e) {
Set < String > keySet = object.keySet();
for (String key: keySet) {
System.out.println(object.get(key));
}
e.printStackTrace();
}
}
UPDATE #2:
Another issue is that I will never know the names of the JSON object and count of child objects (update JSON and CSV examples as well to make the image more clear). All that is known, that it will always start with strings object.
Library used:
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20180813</version>
</dependency>
So found a solution by myself:
public static void jsonToCsv() throws JSONException, IOException {
InputStream is = MainClass.class.getResourceAsStream("/fromJson.json");
JSONTokener jsonTokener = new JSONTokener(is);
JSONObject jsonObject = new JSONObject(jsonTokener).getJSONObject("strings");
builder = new StringBuilder();
while (!jsonObject.isEmpty()) {
stepInto(jsonObject);
}
String[] lines = builder.toString().split("\n"); // builder lines are in reverse order from expected so this array is used to reverse them
FileWriter csvWriter = new FileWriter("src/main/resources/toCsv.csv");
csvWriter.append("Keys,Default (en_US)\n");
for (int i = lines.length - 1; i >= 0; i--) {
csvWriter.append(lines[i]).append("\n");
}
csvWriter.flush();
csvWriter.close();
}
private static void stepInto(JSONObject jsonObject) {
for (String key: jsonObject.keySet()) {
Object object = jsonObject.get(key);
if (object instanceof JSONObject) {
builder.append(key).append(".");
stepInto(jsonObject.getJSONObject(key));
} else {
builder.append(key).append(",").append(object).append("\n");
jsonObject.remove(key);
break;
}
if (jsonObject.getJSONObject(key).isEmpty()) {
jsonObject.remove(key);
}
break;
}
}
I think you just missed keeping track of your result, otherwise it looks good.
Let's say your result is a simple string. Then you have to concatenate all keys while traversing the json object until you reach a primitive value (like a number or a string).
(I am writing this out of my head, so please forgive me for incorrect syntax)
private static String stepInto(JSONObject jsonObject) { // we change "void" to "String" so we can record the results of each recursive "stepInto" call
//JSONObject object = jsonObject; // we don't need that. Both variables are the same object
String result ="";
try {
for (String key: jsonObject.keySet()) { // shorter version
Object object = jsonObject.get(key); // Attention! we get a simple Java Object
if(object instanceof JSONObject){
result+= key+"."+stepInto(jsonObject.getJSONObject(key)); // the recursive call, returning all keys concatenated to "level1.level2.level3" until we reach a primitive value
}
if(object instanceof JSONArray){
result+= key+", "+ ... // notice how we use the csv separator (comma) here, because we reached a value. For you to decide how you want to represent arrays
}
result+= key +", "+ object +"\n"; // here I am not sure. It may well be that you need to check if object is a String an Integer, Float or anything.
}
} catch (JSONException e) {
for (String key: jsonObject.keySet()) {
System.out.println(object.get(key));
}
e.printStackTrace();
result+= "\n"; // I added this fallback so your program can terminate even when an error occurs.
}
return result; // sorry, I forgot to accumulate all results and return them. So now we have only one actual "return" statement that will terminate the call and return all results.
}
As you can see, I didn't change much of your original method. The only difference is that now we keep track of the keys ("level1.level2...") for each recursive call.
EDIT
I added a +"\n"; so everytime we reach a value so we can terminate that "line".
AND more importantly, instead of returning everytime, I add the result of each call to a string, so we continue looping over the keys and concatenate all results. Each call of the method will return only once all keys are looped over. (sorry that missed that)
In your calling method you could print out the result, something like that:
JSONObject jsonObject = new JSONObject(jsonTokener);
String result = stepInto(jsonObject);
System.out.println(result);
I have been searching all over, but I still cannot find a solution to my problem. If there is a post made already, please tell me so I can visit it. I have seen similar posts, but they follow a different JSON format than mine, so I wanted to see if it is possible and how it is possible to make it using the JSON format that will be introduced below.
Basically, what I am trying to do is get every element in a JSON file, and retrieve each element's key name and value. Both the key and the value are String values. Here is an example JSON of how I want my JSON code to look like:
{
"Variable1":"-",
"Variable2":" Test "
}
I am using the org.json library, and I would like to know if this is possible, and if it is, how can I achieve it? What I tried to do originally was put the variables under an array named "Variables", but every time I tried getting that array, it gave me an error saying that JSONObject["Variables"] is not a JSONArray. Not sure if this is caused because of a problem in the JDK or because of a problem in my code. That is, of course, a thing to discuss in another thread. So far, this is what I have (FilePath is a String variable that contains the full path to the file):
String Contents = new String((Files.readAllBytes(Paths.get(FilePath))));
JSONObject JsonFile = new JSONObject(Contents);
JSONArray VariableList = JsonFile.getJSONArray("Variables");
for (Object Item: VariableList) {
Map.Entry Item2 = (Map.Entry)Item;
System.out.println("Key: " + Item2.getKey() + ", Value: " + Item2.getValue());
}
The above code should be working if the JSON looked something like this (yes, I said should because it does not work):
{
"Variables": {
"Variable1":"-",
"Variable2":" Test "
}
}
If it is possible, how would I be able to make get the key and value using the first JSON format? If not possible, then how would I do it in an alternative way? Keep in mind, the key name is never going to the same, as the key and value will be different depending on what the user wants them to be, so that is why it is important to be able to loop through every element and get both it's key and value.
Thank you for your time and effort.
"Variables" : { ... } is a JSONObject and not a JSONArray.
For package org.json
try {
String contents = "{\"Variables\":{\"Variable1\":\"-\",\"Variable2\":\" Test \"}}";
JSONObject jsonFile = new JSONObject(contents);
JSONObject variableList = jsonFile.getJSONObject("Variables"); // <-- use getJSONObject
JSONArray keys = variableList.names ();
for (int i = 0; i < keys.length (); ++i) {
String key = keys.getString(i);
String value = variableList.getString(key);
System.out.println("key: " + key + " value: " + value);
}
} catch (Exception e) {
e.printStackTrace();
}
For package JSON.simple
String contents = new String((Files.readAllBytes(Paths.get(FilePath))));
JSONObject jsonFile = new JSONObject(contents);
JSONObject variableList = jsonFile.getJSONObject("Variables"); // <-- use getJSONObject
variableList.keySet().forEach(key -> {
Object value = jsonObj.get(key);
System.out.println("key: "+ key + ", value: " + value);
});
In an XPages application I have in a sessionScope variable the configuration for the application in JSON format.
I wonder how I can get hold of this configuration again in Java?
I tried:
Map<String, Object> sesScope = ExtLibUtil.getSessionScope();
if (null != sesScope.get("configJSON")){
JsonJavaObject jsonObject = new JsonJavaObject();
jsonObject = (JsonJavaObject) sesScope.get("configJSON");
System.out.println("got object?");
System.out.println("json " + jsonObject.toString());
}
In the console I never get to the "got object?" print statement. What am I doing wrong?
The JavaScript method JSON.parse that you use, returns just a plain simple JavaScript object, not the JsonJavaObject. You can't use JavaScript object later in Java without additional unnecessary overhead. Don't use json2.jss, use JsonParser like Paul Withers have told.
Change your code that gets JSON from your Notes field:
#{javascript:
importPackage(com.ibm.commons.util.io.json);
var jsonText = doc.getItemValueString(itemname);
var jsonFactory:JsonFactory = JsonJavaFactory.instanceEx;
var jsonObject = JsonParser.fromJson(jsonFactory, jsonText);
sessionScope.put('configJSON', jsonObject);
}
Modify your provided java code by removing unnecessary line:
Map<String, Object> sesScope = ExtLibUtil.getSessionScope();
if (null != sesScope.get("configJSON")) {
JsonJavaObject jsonObject = (JsonJavaObject) sesScope.get("configJSON");
System.out.println("got object?");
System.out.println("json " + jsonObject.toString());
}
You should now be OK.
Hint: if you use JsonJavaFactory.instance instead of JsonJavaFactory.instanceEx, you'll get java.util.HashMap instead of JsonJavaObject
Has the sessionScope variable been set? Use sesScope.containsKey("configJSON") to verify. If it's an empty JSON object it will be "{}" rather than null. If you're loading as JSON from a REST service or a Notes Document it may be a String rather than a JsonJavaObject. For parsing a String of JSON, you can use com.ibm.commons.util.io.json.JsonParser. The constructor for JsonJavaObject expects a Map, not sure if this is what's being passed in.
JsonJavaObject is your POJO java class ?
If Yes then please use ObjectMapper of Fasterxml to map your JSON data to the fields of JsonJavaObject class.Use this method to map your json data to any POJO class
public final T validateJson(final Map<String, Object> jsonMap, final T temmplateClass) throws Exception {
ObjectMapper objectMapper = new ObjectMapper();
try {
// convert JSON string to Map
String jsonString = objectMapper.writeValueAsString(jsonMap);
return objectMapper.readValue(jsonString, (Class<T>) temmplateClass);
} catch (JsonMappingException e) {
throw new NestableRuntimeException(String.format(ApiCommonConstants.INVALID_JSON_FIELD,
e.getPath().get(e.getPath().size() - 1).getFieldName()));
} catch (IOException e) {
throw new NestableRuntimeException(e.getMessage(), e);
}
}
I am getting the data from the Zookeeper node like this
byte[] bytes = client.getData().forPath("/my/example/node1");
String ss = new String(bytes);
Here ss will have data like this which is a simple JSON String consisting of key value pair -
{"description":"Some Text", "machinename":"machineA", "ipaddress":"192.128.0.0"}
Now I want to append one more key value pair at the end to the above JSON String. This is the below key value pair I want to append -
"version":"v3"
So the final JSON String will look like this -
{"description":"Some Text", "machinename":"machineA", "ipaddress":"192.128.0.0", "version":"v3"}
What's the best and efficient way to do this?
Use a JSON Parser/Generator to parse your given JSON to a tree structure and then add your JSON field.
With Gson, that would look something like this
Gson gson = new Gson();
JsonObject jsonObject = gson.fromJson(ss, JsonObject.class); // parse
jsonObject.addProperty("version", "v3"); // modify
System.out.println(jsonObject); // generate
prints
{"description":"Some Text","machinename":"machineA","ipaddress":"192.128.0.0","version":"v3"}
Will Zookeeper always return valid JSON or their custom format? Be aware of that.
When it comes to JSON processing, string manipulation only works in special and simple cases. For the general case, a good JSON parser library should be used.
Jackson is among the top of such libraries in terms of performance, efficiency, versatility and reliability, plus it is published under the commercial-friendly Apache 2.0 license.
Following is a simple implementation of the requested answer in Jackson.
public static void main(String[] args)
{
String ss = "{\"description\":\"Some Text\", \"machinename\":\"machineA\", \"ipaddress\":\"192.128.0.0\"}";
System.out.println("JSON string before: " + ss);
try
{
ObjectMapper mapper = new ObjectMapper();
Map<String, String> map = (Map<String, String>)mapper.readValue(ss, Map.class);
map.put("version", "v3");
ss = mapper.writeValueAsString(map);
}
catch (Exception e)
{
e.printStackTrace();
}
System.out.println("JSON string after: " + ss);
}
Basic string manipulation. Insert your additional string before the final close brace }. Make sure to add a comma.
Json objects don't need to be ordered.
String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
String json2 = "\"version\":\"v3\"";
json2 = ',' + json2;
String json3 = json.substring(0,json.length()-1) + json2 + json.charAt(json.length()-1);
That should be the simplest, most efficient way, if that's all you need to do.
For additional reading on String manipulation,
http://docs.oracle.com/javase/tutorial/java/data/manipstrings.html