Sprint boot - Auto configure to call a REST service on startup - spring

Question

I have a requirement to create an auto-configuration for service call on spring-boot startup.
i.e., During spring-boot startup, the below service has to be called.
#PostMapping(path = "/addProduct", produces = "application/json", consumes = "application/json")
public #ResponseBody String addProduct(#RequestBody String productStr) {
..<My code>..
}
The add product requires an input like:
{
"product":"test",
"price":"10"
}
This will internally call a database service.
During startup, the json input provided in the console should be fed to this service.
I have no idea on how to achieve this. Verified a couple of Spring documentation. But those does'nt suit the requirement.
Kindly help in explaining a way or providing a right documentation to achieve this.

Answer 1

One way to do this is by implementing ApplicationRunner like this :
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
#Component
public class ApplicationInitializer implements ApplicationRunner {
private ProductController productController;
public ApplicationInitializer(ProductController productController) {
this.productController = productController;
}
#Override
public void run(ApplicationArguments args) throws Exception {
String productArg = args.getOptionValues("product").get(0); // Assume that you will have only one product argument
ObjectMapper mapper = new ObjectMapper();
Product product = mapper.readValue(productArg, Product.class);
String response = productController.add(product);
System.out.println(response);
}
}
The run method will be invoked at startup with arguments passed in the command line like this : java -jar yourApp.jar --product="{\"name\":\"test\", \"price\":\"15\"}".
And you need a class to map the json to an object like this :
public class Product {
private String name;
private int price;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getPrice() {
return price;
}
public void setPrice(int price) {
this.price = price;
}
}
You can also call your Controller using the RestTemplate (or WebClient) if needed :
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
#Component
public class ApplicationInitializer implements ApplicationRunner {
#Override
public void run(ApplicationArguments args) throws Exception {
String productArg = args.getOptionValues("product").get(0); // Assume that you will have only one product argument
ObjectMapper mapper = new ObjectMapper();
Product product = mapper.readValue(productArg, Product.class);
RestTemplate restTemplate = new RestTemplate();
String response = restTemplate.postForObject("http://localhost:8080/products", product, String.class);
System.out.println(response);
}
}

Answer 2

Such requirement can be achieved by using an init() method annotated with #PostConstruct in a bean.
e.g.
#Component
public class Foo {
#PostConstruct
public void init() {
//Call your service
}
}