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How to convert json file to excel file in java

I,m given a problem to convert JSON file to excel file, in short to convert JSON data to excel data. Tried mapping JSON keys and values but can't do it.
Tried mapping JSON keys and values but can't do it. I have already used apache POI api.
public class jsontoexcel {
public static void main(String[] args) throws IOException,JSONException {
jsontoexcel json4=new jsontoexcel();
JSONObject json=json4.ReadJson();
JSONArray array =new JSONArray();
JSONObject rowjson=json.getJSONArray("rows").getJSONObject(0);
XSSFWorkbook workbook=new XSSFWorkbook();
XSSFSheet sheet=workbook.createSheet("Company Details");
int len=rowjson.length();
String[] RowArr=new String[len];
Iterator<String> keys = rowjson.keys();
int i=0;
while(keys.hasNext())
{
RowArr[i]=keys.next();
System.out.print("key:"+keys);
i++;
}
List<String> slist= new ArrayList<String>();
slist=json.get(rowjson.toString(keys));
FileOutputStream out=new FileOutputStream(new File("C:\\code\\eclipse\\jsontoexcel\\src\\output.xlsx"));
createHeaderRow(sheet, RowArr);
workbook.write(out);
out.close();
// Map<String,Object> map=new Map<String,Object>();
}
public static void createHeaderRow(XSSFSheet sheet, String[] RowArr)
{
Row row=sheet.createRow(0);
for(int i=0;i<RowArr.length-1;i++)
{
Cell cellTitle=row.createCell(i+1);
String cellVal=RowArr[i];
System.out.print("Cell data" + cellVal);
}
}
}
I expect the output to be stored in an excel file. The headers are getting printed but not the values.

Do not generate Excel file until you really have to. In case, you want to generate data without any specific formatting, charts, macros, etc. just generate CSV file with pure data. To read JSON and generate CSV you can use Jackson library which supports these two data formats. Just assume your JSON looks like below:
{
"rows": [
{
"id": 1,
"name": "Vika",
"age": 27
},
{
"id": 2,
"name": "Mike",
"age": 28
}
]
}
You, need to create POJO model which fits to that structure, deserialise JSON to objects and serialise objects to CSV format. Example solution, could look like below:
import com.fasterxml.jackson.annotation.JsonPropertyOrder;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SequenceWriter;
import com.fasterxml.jackson.dataformat.csv.CsvMapper;
import com.fasterxml.jackson.dataformat.csv.CsvSchema;
import java.io.File;
import java.util.List;
public class JsonApp {
public static void main(String[] args) throws Exception {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
ObjectMapper jsonMapper = new ObjectMapper();
Response response = jsonMapper.readValue(jsonFile, Response.class);
CsvMapper csvMapper = new CsvMapper();
CsvSchema schema = csvMapper.schemaFor(Item.class).withHeader();
SequenceWriter sequenceWriter = csvMapper.writer(schema).writeValues(System.out);
sequenceWriter.writeAll(response.getRows());
}
}
class Response {
private List<Item> rows;
// getters, setters
}
#JsonPropertyOrder({"id", "name", "age"})
class Item {
private int id;
private String name;
private int age;
// getters, setters
}
Above code prints:
id,name,age
1,Vika,27
2,Mike,28
See also:
jackson-dataformats-text
Intro to the Jackson ObjectMapper

XML to JSON Conversion with Conditions

Wanted to covert an xml String to Json and I am doing it as below.
XML which has to be converted
<Item>
<Property name="Description" value="Description 1"/>
<Property name="EffDate" value="01/05/2017"/>
<Property name="ExpDate" value="12/31/9999"/>
<Property name="Status" value="Launched"/>
</Item>
I have created a Class for the xml as below.
public class Context {
#XmlElement(name = "Item")
private List<Item> offer;
}
public class Item {
#XmlElement(name = "Property")
private List<Property> properties;
}
public class Property {
#XmlAttribute
private String name;
#XmlAttribute
private String value;
}
I am using Gson libraries to convert this Java object to Json - g.toJson.
Comverted JSON -
"offer": [{
"properties": [{
"name": "Description",
"value": "Description 1"
},
{
"name": "EffDate",
"value": "01/05/2017"
},
{
"name": "ExpDate",
"value": "12/31/9999"
},
{
"name": "Status",
"value": "Launched"
}]
}]
But we wanted to convert the JSON as below -
"offer": [{
"Description" : "Description 1",
"EffDate":"01/05/2017",
"ExpDate": "12/31/9999",
"Status": "Launched"
}]
Is there a way to convert the properties name and value as Item class properties.?

Try using this link: https://github.com/stleary/JSON-java This is a JSON Helper class that can convert XML to JSON for example:
public class Main {
public static int PRETTY_PRINT_INDENT_FACTOR = 4;
public static String TEST_XML_STRING =
"<?xml version=\"1.0\" ?><test attrib=\"moretest\">Turn this to JSON</test>";
public static void main(String[] args) {
try {
JSONObject xmlJSONObj = XML.toJSONObject(TEST_XML_STRING);
String jsonPrettyPrintString = xmlJSONObj.toString(PRETTY_PRINT_INDENT_FACTOR);
System.out.println(jsonPrettyPrintString);
} catch (JSONException je) {
System.out.println(je.toString());
}
}
}
Hope this helps :)

It is possible using FasterXML library. where you can write your custom logic for generating XML and JSON. By overriding serialize of JsonSerializer class.
Need to write Serializer like :
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import java.io.IOException;
public class ContextSerializer extends JsonSerializer<Context> {
#Override
public void serialize(Context t, JsonGenerator jg, SerializerProvider sp) throws IOException, JsonProcessingException {
jg.writeStartObject();
jg.writeArrayFieldStart("offer");
for (Item i : t.offer) {
jg.writeStartObject();
for (Property property : i.properties) {
jg.writeStringField(property.name, property.value);
}
jg.writeEndObject();
}
jg.writeEndArray();
jg.writeEndObject();
}
}
For convert:
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.JAXBException;
public class Main {
public static void main(String[] args) throws JAXBException, JsonProcessingException {
Context c = new Context();
List<Item> offer = new ArrayList<>();
Item pr = new Item();
pr.properties = new ArrayList<>();
Property p = new Property();
p.name = "asdf";
p.value = "va1";
pr.properties.add(p);
p = new Property();
p.name = "asdf1";
p.value = "va11";
pr.properties.add(p);
offer.add(pr);
c.offer = offer;
try {
SimpleModule module = new SimpleModule();
module.addSerializer(Context.class, new ContextSerializer());
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.registerModule(module);
objectMapper.setSerializationInclusion(Include.NON_DEFAULT);
String json = objectMapper.writeValueAsString(c);
System.out.println(json);
} catch (Exception e) {
System.out.println(""+e);
}
}
}
O/P JSON : (Provided O/P JSON is wrong in your question if you give the name to the list("offer") then it always inside object link)
{
"offer": [{
"asdf": "va1",
"asdf1": "va11"
}
]
}
Maven Dependency for package is:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.9.0.pr3</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.0.pr3</version>
</dependency>

If you are using Java 8 or later, you should check out my open source library: unXml. unXml basically maps from Xpaths to Json-attributes.
It's available on Maven Central.
Example
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.nerdforge.unxml.factory.ParsingFactory;
import com.nerdforge.unxml.parsers.Parser;
import org.w3c.dom.Document;
public class Parser {
public ObjectNode parseXml(String xml){
Parsing parsing = ParsingFactory.getInstance().create();
Document document = parsing.xml().document(xml);
Parser<ObjectNode> parser = parsing.obj("/")
.attribute("offer", parsing.arr("/Item")
.attribute("Description", "Property[#name='Description']/#value")
.attribute("EffDate", "Property[#name='EffDate']/#value")
.attribute("ExpDate", "Property[#name='ExpDate']/#value")
.attribute("Status", "Property[#name='Status']/#value")
)
.build();
ObjectNode result = parser.apply(document);
return result;
}
}
It will return a Jackson ObjectNode, with the following json:
{
"offer": [
{
"Status": "Launched",
"Description": "Description 1",
"ExpDate": "12/31/9999",
"EffDate": "01/05/2017"
}
]
}

You may convert xml to a map, modify it and then convert to a json. Underscore-java library has static methods U.fromXml(xml) and U.toJson(json). I am the maintainer of the project.

Trying to read values from array nested in JSON

I've been writing a Rest service using Jackson to extract the name and sizeFromStorage inside the response value.
I created the below classes in an attempt to do this:
import java.util.List;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
#JsonIgnoreProperties(value = {"status", "header"})
public class Vaults {
private List<Object> response;
public Vaults(){
}
public Vaults(List<Object> response){
this.response = response;
}
public List<Object> getResponse(){
return response;
}
public void setResponse(List<Object> response) {
this.response = response;
}
#Override
public String toString() {
return "" + response;
}
}
import java.io.IOException;
import java.util.List;
import java.util.ArrayList;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.CollectionType;
import java.io.InputStream;
public class JacksonObjectModelTest {
public static void main(String[] args) throws IOException {
String jsonFileName = "/JsonRead/json.json";
List<Vaults> emps = new JacksonObjectModelTest().getVaultList(jsonFileName);
System.out.println(emps.toString());
}
public ArrayList<Vaults> getVaultList(String jsonFileName) throws IOException {
//read json file data to String
InputStream inputStream = getClass().getResourceAsStream(jsonFileName);
//create ObjectMapper instance
ObjectMapper objectMapper = new ObjectMapper().enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
//convert json string to object
CollectionType collectionType = objectMapper.getTypeFactory().constructCollectionType(List.class, Vaults.class);
ArrayList<Vaults> emps = objectMapper.readValue(inputStream, collectionType);
return (ArrayList<Vaults>) emps;
}
}
{
"status": "ok",
"header": {
"now": 1491545894581,
"status": "ok",
"requestId": "WOcvJsCoAmoAAESbkBYAAAB5"
},
"response": {
"vault": [
{
"id": 20,
"name": "Apple",
"description": "",
"sizeFromStorage": 95957225298,
"storagePools": [
{
"storagePool": {
"id": 1,
"name": "storage-pool1",
"sizeFromStorage": 95957225298,
"generations": [
{
"generation": {
"sequence": 0
}
}
]
}
}
]
},
{
"id": 21,
"name": "Banana",
"description": "",
"sizeFromStorage": 98957268244,
"storagePools": [
{
"storagePool": {
"id": 2,
"name": "storage-pool1",
"sizeFromStorage": 98957268244,
"generations": [
{
"generation": {
"sequence": 0
}
}
]
}
}
]
},
]
}
}
The output I get from this is:
[[{vaults=[{id=20, name=Apple, description=, sizeFromStorage=95957225298, storagePools=[{storagePool={id=1, name=storage-pool1, sizeFromStorage=5043, estimateUsableTotalLogicalSizeFromStorage=95957225298, generations=[{generation={sequence=0}}]}}]}, {id=20, name=Apple, description=, sizeFromStorage=95957225298, storagePools=[{storagePool={id=1, name=storage-pool1, sizeFromStorage=5043, estimateUsableTotalLogicalSizeFromStorage=95957225298, generations=[{generation={sequence=0}}]}}]}]]
However, what I want to do is the name and sizeFromStorage values. So far I've managed to strip out the first three values. Unfortunately I'm now stuck as I'm not very familiar with Rest services or reading JSON. Is there any way I can delve further into the JSON to get what I need or have I approached this in the wrong way?
Additional info:
Since posting my original question I came up with this(based on something I saw on a different site):
package JsonRead;
import java.io.File;
import java.io.IOException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
public class JacksonTreeModel {
public static void main(String[] args) {
try{
ObjectMapper mapper = new ObjectMapper();
JsonNode root = mapper.readTree(new File("JsonRead/json.json"));
JsonNode vaultsNode = root.path("response").path("vault");
/*if(vaultsNode.isArray()){
for(JsonNode node : vaultsNode){
String name = node.path("name").asText();
System.out.println("Array Name: " + name);
}
}*/
for(JsonNode node : vaultsNode){
String name = node.path("name").asText();
String bytesUsed = node.path("sizeFromStorage").asText();
System.out.println("Name: " + name + ", Bytes Used: " + bytesUsed);
}
} catch(IOException e){
System.out.println("IO Exception " + e );
}
}
}
It works for what I want but is there a better way to do this?
Will, thanks for the response. I'll look into your suggestion.

Ok, so i just re-read your question.
Recommend creating yourself a VaultDAO object with a more meaningful custom object type to use for the response collections. Prvoided you use the same variable names (which it looks like are known to you) then it should deserialize for you

how to apply Json serialization or deserialization in request and response to HTTP method of rest api

I am very new to Rest api in java .My Question is how to directly convert json string request to java class object before post or get function ,like
json string : '{"id":3,"name":name}'
rest api post method :
#Post
public Something postData(Something obj) throws Exception {
}
so how to apply json serialization before request to this method.
right now i am converting it inside postData method.

You can use Jackson API to play with JSON.
For the Following JSON data the Java object mapping can be done as follows.
{
"id": 123,
"name": "Pankaj",
"permanent": true,
"address": {
"street": "Albany Dr",
"city": "San Jose",
"zipcode": 95129
},
"phoneNumbers": [
123456,
987654
],
"role": "Manager",
"cities": [
"Los Angeles",
"New York"
],
"properties": {
"age": "29 years",
"salary": "1000 USD"
}
}
import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.journaldev.jackson.model.Address;
import com.journaldev.jackson.model.Employee;
public class JacksonObjectMapperExample {
public static void main(String[] args) throws IOException {
//read json file data to String
byte[] jsonData = Files.readAllBytes(Paths.get("employee.txt"));
//create ObjectMapper instance
ObjectMapper objectMapper = new ObjectMapper();
//convert json string to object
Employee emp = objectMapper.readValue(jsonData, Employee.class);
System.out.println("Employee Object\n"+emp);
//convert Object to json string
Employee emp1 = createEmployee();
//configure Object mapper for pretty print
objectMapper.configure(SerializationFeature.INDENT_OUTPUT, true);
//writing to console, can write to any output stream such as file
StringWriter stringEmp = new StringWriter();
objectMapper.writeValue(stringEmp, emp1);
System.out.println("Employee JSON is\n"+stringEmp);
}
public static Employee createEmployee() {
Employee emp = new Employee();
emp.setId(100);
emp.setName("David");
emp.setPermanent(false);
emp.setPhoneNumbers(new long[] { 123456, 987654 });
emp.setRole("Manager");
Address add = new Address();
add.setCity("Bangalore");
add.setStreet("BTM 1st Stage");
add.setZipcode(560100);
emp.setAddress(add);
List<String> cities = new ArrayList<String>();
cities.add("Los Angeles");
cities.add("New York");
emp.setCities(cities);
Map<String, String> props = new HashMap<String, String>();
props.put("salary", "1000 Rs");
props.put("age", "28 years");
emp.setProperties(props);
return emp;
}
}
Source : http://www.journaldev.com/2324/jackson-json-processing-api-in-java-example-tutorial

You can use Gson or do a manually serialization/deserialization using JSONObject/JSONArray classes (example here). There are many other ways/libs to do this.

get nested Object using json-simple - Wildcard for parent Node

I want to retrieve "name" values and store them in an Arraylist from a JSON file in Java. I am using JSON-simple library Here is an example of my "file.json":
{
"111": {
"customer": {
"name": "John Do",
"Height": 5.9,
"City": "NewYork"
}
},
"222":{
"customer": {
"name": "Sean Williams",
"Height": 6,
"City": "Los Angeles"
}
}
}
Id numbers "111" and "222" are not significant for my program and they are randomly generated so I am not able to use jObject.get() as the values will constantly be changing. I tried searching for a wildcard for the parent Node and then go to child node customer and then name but haven't found such thing.
Here is my code so far:
import java.io.*;
import java.util.ArrayList;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
public class npTest {
public static void main(String[] args) throws IOException, ParseException {
try {
JSONParser jParser = new JSONParser();
JSONObject jObject = (JSONObject) jParser.parse(new FileReader("file.json"));
//Notes
} catch (FileNotFoundException e) {
System.out.print("File not found!");
}
}
}
Notes: methods I have tried require jObject.get("id"). Also I noticed I am not able to store the JSONObject in another JSONObject, for example: JSONObject parentObj = new JSONObject(jObject.get("111"));

You can iterate through the keys in a JSONObject using the keySet() method. Then pull out your "customer" and get their name.
JSONParser jParser = new JSONParser();
JSONObject jObject = (JSONObject) jParser.parse(new FileReader("c:\\file.json"));
for(Object key : jObject.keySet()) {
JSONObject customerWrapper = (JSONObject)jObject.get(key);
JSONObject customer = (JSONObject)customerWrapper.get("customer");
System.out.println(customer.get("name"));
}

JSONObject implements the Map interface. So you could query for all map keys with normal Java syntax:
for (Object innnerO : jObject.values()){
JSONObject customerO = (JSONObject)((JSONObject)innerO).get("customer");
}
Note: This is written out of my head without compiler. So there might me errors.