Saving arrays of elements in the json object into different rows - json

Question

While saving json object containing multiple jsons, the json object is being saved as a single array instead of multiple rows.
sample json:
[
{
"id" : 1, -- this is not a primary key and not unique but cannot be null
"name" : "John Doe",
"phone" : [
{ "type" : "home", "ref" : "111-111-1234"},
{ "type" : "work", "ref" : "222-222-2222"}
]
},
{
"id" : 2, -- this is not a primary key and not unique but cannot be null
"name" : "Jane Doe",
"phone" : [
{ "type" : "home", "ref" : "111-111-1234"},
{ "type" : "work", "ref" : "222-222-2222"}
]
}
]
This is what i need after saving in the database
id name phone
1 John Doe { "type" : "home", "ref" : "111-111-1234"}
1 John Doe { "type" : "work", "ref" : "222-222-2222"}
2 Jane Doe { "type" : "home", "ref" : "111-111-1234"}
2 Jane Doe { "type" : "work", "ref" : "222-222-2222"}
This is what I am getting
id name phone
1 John Doe [{ "type" : "home", "ref" : "111-111-1234"},{ "type" : "work", "ref" : "222-222-2222"}]
2 Jane Doe [{ "type" : "home", "ref" : "111-111-1234"},{ "type" : "work", "ref" : "222-222-2222"}]
here is how i am parsing the json object to pojo and saving to db
#Entity
#Table(name="person")
public class person{
private Integer id;
private String name;
private String phone;
#Transient
JsonNode phoneJson;
private static OhjectMapper mapper = new ObjectMapper();
getter/setter
#Transient
public JsonNode getPhoneJson(){
return phoneJson;
}
public void setPhoneJson(JsonNode phoneJson){
this.phoneJson = phoneJson;
}
#JsonIgnore
#Column(name="phone")
public String getPhone() throws Exception{
return mapper.writeValueAsString(phoneJson);
}
public void setPhone(String phone) throws Exception{
this.phone = mapper.readTree(phone);
}
}
dao- save
personRepository.save(person)
any help would be appreciated.
UPDATE
Multiple jSON Column
[
{
"id" : 1, -- this primary key and not unique but cannot be null
"name" : { --this element can be empty/null
"first" : "John",
"last" : "Doe"
},
"phone" : [
{ "type" : "home", "ref" : 1111111234},
{ "type" : "work", "ref" : 2222222222}
]
},
{
"id" : 2, -- this primary key and not unique but cannot be null
"name" : {
"first" : "Jane",
"last" : "Doe"
},
"phone" : [
{ "type" : "home", "ref" : 1111111234},
{ "type" : "work", "ref" : 2222222222}
]
}
]
how do i get result as below
id name phone
1 [{John},{Doe}] { "type" : "home", "ref" : "111-111-1234"}
1 [{John},{Doe}] { "type" : "work", "ref" : "222-222-2222"}
2 [{Jane},{Doe}] { "type" : "home", "ref" : "111-111-1234"}
2 [{Jane},{Doe}] { "type" : "work", "ref" : "222-222-2222"}

Answer 1

You need to duplicate Person objects n times where n is size of phone array. To make it clear, I propose, to create two separate models which we can use separately for parsing JSON and saving in DB. Below you can find simple example which:
Parses JSON to List<JsonPerson>
Converts List<JsonPerson> to List<Person>
Prints List<Person> (you can save it to DB)
Example:
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.type.CollectionType;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
public class JsonApp {
public static void main(String[] args) throws Exception {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
ObjectMapper mapper = new ObjectMapper();
CollectionType personsType = mapper.getTypeFactory().constructCollectionType(List.class, JsonPerson.class);
// parse
List<JsonPerson> jsonPersons = mapper.readValue(jsonFile, personsType);
// convert
List<Person> persons = jsonPersons.stream()
.map(p -> p.mapTo(mapper))
.flatMap(List::stream)
.collect(Collectors.toList());
persons.forEach(System.out::println);
// save persons to DB
// ...
}
}
class JsonPerson {
private Integer id;
private String name;
private ArrayNode phone;
public List<Person> mapTo(ObjectMapper mapper) {
List<Person> persons = new ArrayList<>();
phone.elements().forEachRemaining(phone -> {
persons.add(map(mapper, phone));
});
return persons;
}
private Person map(ObjectMapper mapper, JsonNode p) {
Person person = new Person();
person.setId(id);
person.setName(name);
try {
person.setPhone(mapper.writeValueAsString(p));
} catch (JsonProcessingException e) {
throw new IllegalStateException(e);
}
return person;
}
// getters, setters, toString
}
class Person {
private Integer id;
private String name;
private String phone;
// getters, setters, toString
}
Above code prints:
Person{id=1, name='John Doe', phone='{"type":"home","ref":"111-111-1234"}'}
Person{id=1, name='John Doe', phone='{"type":"work","ref":"222-222-2222"}'}
Person{id=2, name='Jane Doe', phone='{"type":"home","ref":"111-111-1234"}'}
Person{id=2, name='Jane Doe', phone='{"type":"work","ref":"222-222-2222"}'}
Above code separates parsing JSON from other parts. Also, do not create ObjectMapper in each POJO. POJO should not know anything about ObjectMapper and Jackson.
Update
Because name is JSON Object you can create new POJO - Name with first and last properties or treat it similarly to phone and deserialise to JsonNode:
class JsonPerson {
private Integer id;
private JsonNode name;
private ArrayNode phone;
public List<Person> mapTo(ObjectMapper mapper) {
List<Person> persons = new ArrayList<>();
phone.elements().forEachRemaining(phone -> {
persons.add(map(mapper, phone));
});
return persons;
}
private Person map(ObjectMapper mapper, JsonNode p) {
Person person = new Person();
person.setId(id);
person.setName(getNameAsString());
try {
person.setPhone(mapper.writeValueAsString(p));
} catch (JsonProcessingException e) {
throw new IllegalStateException(e);
}
return person;
}
private String getNameAsString() {
if (name == null) {
return null;
}
StringBuilder builder = new StringBuilder();
if (name.isObject()) {
ObjectNode nameObject = (ObjectNode) name;
builder.append("[");
builder.append("{").append(nameObject.get("first")).append("}");
builder.append(",");
builder.append("{").append(nameObject.get("last")).append("}");
builder.append("]");
}
return builder.toString();
}
// getters, setters, toString
}
After change above code should print:
Person{id=1, name='[{"John"},{"Doe"}]', phone='{"type":"home","ref":1111111234}'}
Person{id=1, name='[{"John"},{"Doe"}]', phone='{"type":"work","ref":2222222222}'}
Person{id=2, name='[{"Jane"},{"Doe"}]', phone='{"type":"home","ref":1111111234}'}
Person{id=2, name='[{"Jane"},{"Doe"}]', phone='{"type":"work","ref":2222222222}'}
getNameAsString method is simplified, you need to handle all corner cases and create String representation better for null, empty and semi-empty nodes.