Spring Rest -> Hibernate entity to JSON - spring

Question

I am creating REST API using spring framework. My entity is based on one table and REST API is supposed to be invoked using POST operation with below JSON structure. Can someone explain me how to map the entity class so that it can consume below-shown json.
Since my entity is based on only one table, I am not able to understand how can it create nested json objects for same table properties.
{
"process_ar_receipt": {
"message_header": {
"source_system_guid": "DDED-DBCD-REV-E1F4343DB3434",
"source_system": "MeSo_TravelAds"
},
"receipt_header": {
"customer_number": "123",
"source_receipt_number": "TESTRCPT_1523",
}
}
}

Answer 1

you could use Gson to convert the json to a DTO
https://jarroba.com/gson-json-java-ejemplos/

Answer 2

pseudo code
assuming your Entity class as
#Entity(name="foo")
class Data{
#Id
private String source_system_guid;
#Column
private String source_system;
#Column
private String customer_number;
#Column
private String source_receipt_number;
public Data() {}
public Data(String ssId, String sourceSystm, String custNum, String srcRcptNum) {
this.source_system_guid = ssId;
this.source_system = sourceSystm;
this.customer_number = custNum;
this.source_receipt_number = srcRcptNum;
}
public String getSource_system_guid() {
return source_system_guid;
}
public void setSource_system_guid(String source_system_guid) {
this.source_system_guid = source_system_guid;
}
public String getSource_system() {
return source_system;
}
public void setSource_system(String source_system) {
this.source_system = source_system;
}
public String getCustomer_number() {
return customer_number;
}
public void setCustomer_number(String customer_number) {
this.customer_number = customer_number;
}
public String getSource_receipt_number() {
return source_receipt_number;
}
public void setSource_receipt_number(String source_receipt_number) {
this.source_receipt_number = source_receipt_number;
}
}
Now since your DTO/BO i.e. Data Transfer Object or Business Object is different from the actual entity we will create the required BO object as below
class DataTO{
#JsonProperty("process_ar_receipt")
private ReceiptTO receiptTO=new ReceiptTO();
public ReceiptTO getReceiptTO() {
return receiptTO;
}
public void setReceiptTO(ReceiptTO receiptTO) {
this.receiptTO = receiptTO;
}
}
class ReceiptTO{
#JsonProperty("message_header")
private MessageHeader messageHeder = new MessageHeader();
#JsonProperty("receipt_header")
private ReceiptHeader receiptHeder = new ReceiptHeader();
public MessageHeader getMessageHeder() {
return messageHeder;
}
public void setMessageHeder(MessageHeader messageHeder) {
this.messageHeder = messageHeder;
}
public ReceiptHeader getReceiptHeder() {
return receiptHeder;
}
public void setReceiptHeder(ReceiptHeader receiptHeder) {
this.receiptHeder = receiptHeder;
}
}
class MessageHeader{
#JsonProperty("source_System_Guid")
private String sourceSystemId;
#JsonProperty("system_Id")
private String systemId;
public String getSourceSystemId() {
return sourceSystemId;
}
public void setSourceSystemId(String sourceSystemId) {
this.sourceSystemId = sourceSystemId;
}
public String getSystemId() {
return systemId;
}
public void setSystemId(String systemId) {
this.systemId = systemId;
}
}
class ReceiptHeader{
#JsonProperty("customer_number")
private String customerNumber;
#JsonProperty("source_rcpt_number")
private String sourceReceiptNumber;
public String getCustomerNumber() {
return customerNumber;
}
public void setCustomerNumber(String customerNumber) {
this.customerNumber = customerNumber;
}
public String getSourceReceiptNumber() {
return sourceReceiptNumber;
}
public void setSourceReceiptNumber(String sourceReceiptNumber) {
this.sourceReceiptNumber = sourceReceiptNumber;
}
}
The #JsonProperty annotation is imported from org.codehaus.jackson.annotate.JsonProperty; i.e from jackson jar
Now a Simple Test class to demo DTO/BO back and forth Entity conversion
public class Test{
public static void main(String[] args) throws JsonGenerationException, JsonMappingException, IOException {
List<Data> datas = new ArrayList<Data>();
datas.add(new Data("DDED-DBCD-REV-E1F4343DB3434","MeSo_TravelAds","123","TESTRCPT_1523"));
datas.add(new Data("ADED-EWQD-REV-E1F4343YG3434","FooSo_MusicAds","132","TESTRCPT_1523"));
datas.add(new Data("YDED-YUTR-REV-E1F43UIDB3434","BarSo_HealthAds","143","TESTRCPT_1523"));
List<DataTO> dataTOs = new ArrayList<DataTO>();
for (Data data : datas) {
DataTO dataTO = new DataTO();
dataTO.getReceiptTO().getMessageHeder().setSourceSystemId(data.getSource_system_guid());
dataTO.getReceiptTO().getMessageHeder().setSystemId(data.getSource_system());
dataTO.getReceiptTO().getReceiptHeder().setCustomerNumber(data.getCustomer_number());
dataTO.getReceiptTO().getReceiptHeder().setSourceReceiptNumber(data.getSource_receipt_number());
dataTOs.add(dataTO);
}
ObjectMapper mapper = new ObjectMapper();
String str = mapper.writeValueAsString(dataTOs);
System.out.println(str);
}
}
This will give you below result
[
{
"process_ar_receipt":{
"message_header":{
"source_System_Guid":"DDED-DBCD-REV-E1F4343DB3434",
"system_Id":"MeSo_TravelAds"
},
"receipt_header":{
"customer_number":"123",
"source_rcpt_number":"TESTRCPT_1523"
}
}
},
{
"process_ar_receipt":{
"message_header":{
"source_System_Guid":"ADED-EWQD-REV-E1F4343YG3434",
"system_Id":"FooSo_MusicAds"
},
"receipt_header":{
"customer_number":"132",
"source_rcpt_number":"TESTRCPT_1523"
}
}
},
{
"process_ar_receipt":{
"message_header":{
"source_System_Guid":"YDED-YUTR-REV-E1F43UIDB3434",
"system_Id":"BarSo_HealthAds"
},
"receipt_header":{
"customer_number":"143",
"source_rcpt_number":"TESTRCPT_1523"
}
}
}
]
similarly the other conversion
String input = "{ \r\n" +
" \"process_ar_receipt\":{ \r\n" +
" \"message_header\":{ \r\n" +
" \"source_System_Guid\":\"ADED-EWQD-REV-E1F4343YG3434\",\r\n" +
" \"system_Id\":\"FooSo_MusicAds\"\r\n" +
" },\r\n" +
" \"receipt_header\":{ \r\n" +
" \"customer_number\":\"132\",\r\n" +
" \"source_rcpt_number\":\"TESTRCPT_1523\"\r\n" +
" }\r\n" +
" }\r\n" +
" }";
DataTO dataTO = mapper.readValue(input, DataTO.class);
System.out.println(dataTO.getReceiptTO().getMessageHeder().getSourceSystemId());
System.out.println(dataTO.getReceiptTO().getMessageHeder().getSystemId());
System.out.println(dataTO.getReceiptTO().getReceiptHeder().getCustomerNumber());
System.out.println(dataTO.getReceiptTO().getReceiptHeder().getSourceReceiptNumber());
this will print
ADED-EWQD-REV-E1F4343YG3434
FooSo_MusicAds
132
TESTRCPT_1523
You dont have to use the mapper code you can directly add the jackson converter as HttpMessageConverted which will convert the JSON to java object automatically
#Configuration
#EnableWebMvc
public class WebConfiguration extends WebMvcConfigurerAdapter {
... other configurations
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
builder.serializationInclusion(JsonInclude.Include.NON_NULL);
builder.propertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);
builder.serializationInclusion(Include.NON_EMPTY);
builder.indentOutput(true).dateFormat(new SimpleDateFormat("yyyy-MM-dd"));
converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
converters.add(new MappingJackson2XmlHttpMessageConverter(builder.createXmlMapper(true).build()));
}
}