I have a controller endpoint that takes EmployeeRequest as shown below:

{
    "name": "Marry Boython",
    "email": "[email protected]",
    "country": "UK",
    "age": "25"         
}

For creating multiple employees, I use a static list in the Application class so that they are populated to the database when running the app. However, I want to create these employees from a json file and sending List<EmployeeRequest> to the service.

I tried the following aproach, but not sure where I point the location of my json file. So, is that the right approach that I am looking to read json and send list of the items in it to the service?

@PostMapping(
            value = "/createAll", consumes = "application/json", produces = "application/json")
public ResponseEntity<List<EmployeeDto>> createAll(
        @RequestBody List<EmployeeRequest> requests) {
    final List<EmployeeDto> employees = employeeService.create(requests);
    return ResponseEntity.ok(employees);
}

CodePudding user response：

Ok from my understanding you would need no body as request input. Instead, you'd want a controller that takes as input a file name so that you can dynamically load a .json file. Your controller method would look something like this:

private final ObjectMapper mapper;

private final ResourceLoader resourceLoader;

public Controller(ObjectMapper mapper, ResourceLoader resourceLoader) {
    this.mapper = mapper;
    this.resourceLoader = resourceLoader;
}

@PostMapping("/load/{fileName}")
public void loadResource(@PathParam("fileName") String fileName) throws IOException {
    Resource resource =resourceLoader.getResource("classpath:" fileName);
    log.debug("Found file "   resource.getFile().getAbsolutePath());
    List<Person> people = mapper.readValue(resource.getFile(), new TypeReference<>() {
    });
    log.info(String.valueOf(people));
}

Where the People.class would be your list of objects that are contained in the json file (EmployeeRequest)

Your .json files would need to be placed with this structure:

CodePudding user response：

Yes. If you already have this JSON file, keep it on resources folder. Then read the JSON file. You should write the business logic on service class that looking and put files' data into the Database.

Update implementation:

If you use maven project, update maven repository:

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
</dependency>

Now follow the code:

Put this JSON "Employee.json"(Any name but update as well) into resources folder.

@RestController
@RequestMapping("/createAll")
public class EmployeeController {
    @Autowired
    private EmployeeService employeeService;

    @PostMapping
    public ResponseEntity<String> createAll() {
        employeeService.create();
        return new ResponseEntity<>("Employees Inserted to DB", HttpStatus.CREATED);
    }
}

@Service
public class EmployeeService {
    // @Autowired
    // private EmployeeRepository employeeRepository;
    public void create() {
        try {
            File resource = new ClassPathResource("Employee.json").getFile();
            String employeeJson = new String(Files.readAllBytes(resource.toPath()));
            Type listType = new TypeToken<ArrayList<EmployeeDto>>() {}.getType();
            List<EmployeeDto> employees = new Gson().fromJson(employeeJson, listType);
            // Call repository method to save employee list
            // employeeRepository.saveAll(employees);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

Hope your problem will be solved.