Spring Boot Rest Template Example

package com.javaexp;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@SpringBootApplication
public class ResttemplateApplication {
  private static final Logger log = LoggerFactory.getLogger(ResttemplateApplication.class);
  public static void main(String args[]) {
    log.info("about to call ResttemplateApplication.run()");
    SpringApplication.run(ResttemplateApplication.class, args);
    log.info("completed executing ResttemplateApplication.run()");
  }
}

package com.bootng;

import java.util.Iterator;
import java.util.Map.Entry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.core.annotation.Order;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
import com.fasterxml.jackson.databind.JsonNode;

/**
 * This Class List all the endpoints from URL https://api.github.com
 *
 */
@Component
@Order(1)
public class LoadAllGithubEndpoints implements CommandLineRunner {
  private static final Logger log = LoggerFactory.getLogger(ResttemplateApplication.class);
  @Override
  public void run(String... args) throws Exception {
    log.info("about to call LoadAllEndpoint.run()");
    RestTemplate restTemplate = new RestTemplateBuilder().build();
    ResponseEntity<JsonNode> apis =
        restTemplate.getForEntity("https://api.github.com", JsonNode.class);
    StringBuilder result = new StringBuilder("\n List of Public API's");
    apis.getBody().fields().next().getValue();
    Iterator<Entry<String, JsonNode>> it = apis.getBody().fields();
    while (it.hasNext()) {
      result.append("\n").append(it.next().getValue().asText());
    }
    log.info(result.toString());
  }
}

package com.bootng;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.core.annotation.Order;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
import com.fasterxml.jackson.databind.JsonNode;

@Component
@Order(2)
public class LoadGithubRepo implements CommandLineRunner {
  private static final Logger log = LoggerFactory.getLogger(ResttemplateApplication.class);
  @Override
  public void run(String... args) throws Exception {
    log.info("about to call LoadGithubRepo.run()");
    RestTemplate restTemplate = new RestTemplateBuilder().build();
    ResponseEntity<JsonNode> repos = restTemplate
        .getForEntity("https://api.github.com/users/bootng/repos", JsonNode.class);
    int counter = 1;
    StringBuilder result = new StringBuilder("\n List of Repositories");
    if (repos.getBody().isArray()) {
      for(JsonNode jsonNode : repos.getBody()) {
        result.append("\n Repo ").append(counter++).append("::");
        result.append(jsonNode.get("name").asText());
      }
    }
    log.info(result.toString());
  }
}