Spring Boot || Tutorial 3 || Returning a Single Resource

Today we will see how to return a single resource when requester sends a request so. Again it's pretty simple. You just need to follow all the steps explained below-

Note: This time we made few changes to the project. We added a service layer and modified controller class. We will see all the changes in details below.

Step-1: We need to add a service layer - that is basically ReturnObjectService class in our project. Copy the below code -

package com.ncteam.thirdtutorial;

import java.util.Arrays;
import java.util.List;

import org.springframework.stereotype.Service;

@Service
public class ReturnObjectService {

public List<ListPojo> listEmployee = Arrays.asList( new ListPojo("Emp1","Kennith", "NJ"),
new ListPojo("Emp2","Jorge", "NC"),
new ListPojo("Emp1","Melanie", "India"));

public List<ListPojo> getEmployeeList(){

return listEmployee;
}

public ListPojo getEmployee(String emplId) {

return listEmployee.stream().filter(t->t.getEmplId().equals(emplId)).findFirst().get();
}
}

Project structure should look like below image -

Step-2: Now we need to modify controller class. Use the below code to do so.

package com.ncteam.thirdtutorial;

import java.util.Arrays;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class ReturnObjectFromController {

@Autowired

private ReturnObjectService service ;

@RequestMapping("/listofpojo")

public List<ListPojo> listAllEmployee() {

return  service.getEmployeeList();

}

@RequestMapping("/listofpojo/{id}")

public ListPojo listEmployee(@PathVariable String id) {

return service.getEmployee(id);

}

}

Project should be looking like below image -

Step-3: Execute the project and hit URL : http://localhost:8080/listofpojo/Emp2

You should be able to get the below screen as output-

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