Hit the Salesforce REST API from Java

Introduction

This article is a reminder of the source code that hits Salesforce's REST API from Java. Since there are many parts that are omitted such as property files, it does not work even if you write it as it is.

For the time being, I would like to know the following three points.

1. How to write to send / receive a request in JSON format
2. How to write to send / receive response in JSON format
3. How to create an array type JSON

Request / response format

request

JSON

{
 "request" : [
   [
      "id" : "000",
      "name" : "sample0"
   ]
   [
      "id" : "001",
      "name" : "sample1"
   ]
 ]
}

response

JSON

{
 "results" : [
   [
      "id" : "000",
      "name" : "sample0",
      "status" : "200"
   ]
   [
      "id" : "001",
      "name" : "sample1",
      "status" : "200"
   ]
 ]
}

Sample code

Java side

ConnectApiLogic.java

public class ConnectApiLogic {

    private static final String LOGIN_URL                   = PropertyUtil.getProperty("SF_LOGIN_URL");
    private static final String GRANT_TYPE                  = PropertyUtil.getProperty("SF_GRANT_TYPE");
    private static final String CLIENT_ID                   = PropertyUtil.getProperty("SF_CLIENT_ID");
    private static final String CLIENT_SECRET               = PropertyUtil.getProperty("SF_CLIENT_SECRET");
    private static final String USERNAME                    = PropertyUtil.getProperty("SF_USERNAME");
    private static final String PASSWORD_AND_SECURITY_TOKEN = PropertyUtil.getProperty("SF_PASSWORD_AND_SECURITY_TOKEN");
    private static String url                               = PropertyUtil.getProperty("SF_RESTPASS") + PropertyUtil.getProperty("SF_UPDATE_USERMST");

    RestTemplate restTemplate = new RestTemplate();

    /**Method to give a list and get the request result*/
    public ResponseDTO getResults(List<RequestChildDTO> requestList) {

        //Get authentication token
        ResponseEntity<ApiTokenResponseDto> apiTokenResponse = doPostAccess(CLIENT_ID, CLIENT_SECRET);
        String authToken = apiTokenResponse.getBody().getAccessToken();
        if (authToken.isBlank()) {
            System.exit(1);
        }

        RequestParentDTO requestDTO = new RequestUserMstDTO();
        requestDTO.request = requestList;

        //Header creation
        MultiValueMap<String, String> headers = new LinkedMultiValueMap<String, String>();
        headers.add("Authorization","Bearer "+authToken);
        headers.add("Content-Type", "application/json");

        restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());

        HttpEntity<RequestParentDTO> request = new HttpEntity<RequestParentDTO>(requestDTO, headers);

        return restTemplate.postForObject(url, request, ResponseParentDTO.class);
    }



    /**Access token acquisition method*/
    private ResponseEntity<ApiTokenResponseDto> doPostAccess(String cliendId, String clientSecret) {

        MultiValueMap<String, String> request = new LinkedMultiValueMap<String, String>();
        request.add("grant_type", GRANT_TYPE);
        request.add("client_id", cliendId);
        request.add("client_secret", clientSecret);
        request.add("username", USERNAME);
        request.add("password", PASSWORD_AND_SECURITY_TOKEN);

        RequestEntity requestEntity = null;
        ResponseEntity<ApiTokenResponseDto> response = null;

        try {
            requestEntity = RequestEntity.post(new URI(LOGIN_URL)).contentType(MediaType.APPLICATION_FORM_URLENCODED).body(request);
            response = restTemplate.exchange(requestEntity, ApiTokenResponseDto.class);
        } catch (URISyntaxException e) {
            e.printStackTrace();
            return response;
        } catch (HttpClientErrorException e) {
            e.printStackTrace();
            return response;
        }
        return response;
    }
}

RequestParentDTO.java

public class RequestParentDTO {
    public List<RequestChildDTO> request;

    public RequestUserMstDTO(){
        request = new ArrayList<>();
    }
}

RequestChildDTO.java

public class RequestChildDTO {

    public String id;
    public String name;

}

ResponseParentDTO.java

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
    "results"
})
public class ResponseParentDTO {

    @JsonProperty("results")
    public List<ResponseChild> results = null;

    public ResponseDTO(){}

}

ResponseChild.java

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
    "id",
    "name",
    "status",
})
public class ResponseChild {

    @JsonProperty("id")
    public String id;
    @JsonProperty("name")
    public String name;
    @JsonProperty("status")
    public String status;

    public Result(){}

}

Salesforce side

PostApi.cls

@RestResource(urlMapping='/sample/*')
global without sharing class PostApi {

    @HttpPost
    global static DT_ResponseParentDto doPost() {
        //Parameter acquisition
        RestRequest req = RestContext.request;
        List<InnerRequest> innnerRequestList = setRequest(req);
        //Return response
        return setResponse(innnerRequestList);
    }



    /**Request parameter acquisition method*/
    private static List<InnerRequest> setRequest(RestRequest req) {
        Map<String, Object> requestParams = (Map<String, Object>) JSON.deserializeUntyped(req.requestBody.ToString());
        List<Object> requestList = (List<Object>) requestParams.get('request');
        List<InnerRequest> innerRequestList = new List<InnerRequest>();
        for (Object obj : requestList) {
            Map<String, Object> params = (Map<String, Object>) obj;
            InnerRequest inner       = new InnerRequest();
            inner.id   = (String) params.get('id');
            inner.name = (String) params.get('name');
            innerRequestList.add(inner);
        }
        return innerRequestList;
    }



    /**Response creation method*/
    private static DT_ResponseParentDto setResponse(List<InnerRequest> innnerRequestList) {
        DT_ResponseParentDto response = new DT_ResponseParentDto();
        //Set the status code in the success list
        if (innnerRequestList.size() > 0) {
            for (InnerRequest inner : innnerRequestList) {
                DT_ResponseChildDto child = new DT_ResponseChildDto();
                child.id                  = inner.id;
                child.name                = inner.name;
                child.status              = "200";
                response.results.add(child);
            }
        }
        return response;
    }



    /**Inner class for request storage*/
    public class InnerRequest {
        public String id;
        public String name;
    }
}

DT_ResponseParentDto.cls

public class DT_ResponseParentDto{

    public List<DT_ResponseChildDto> results;

    public DT_ResponseParentDto() {
        results = new List<DT_ResponseChildDto>();
    }

}

DT_ResponseChildDto.cls

public class DT_ResponseChildDto{

    public String id;
    public String name;
    public String status;

}