步骤：

1. 添加依赖（Spring Boot 已内置，无需额外添加）

2. 创建 RestTemplate Bean

   @Configuration
   public class RestTemplateConfig {
       @Bean
       public RestTemplate restTemplate() {
           return new RestTemplate();
       }
   
   }
   

3. 调用外部接口

@Service
public class ApiService {
    @Autowired
    private RestTemplate restTemplate;

    // GET 请求示例
    public ResponseEntity<String> getData() {
        String url = "https://api.example.com/data";
        return restTemplate.getForEntity(url, String.class);
    }

    // POST 请求示例（带JSON参数）
    public ResponseEntity<String> postData(Object request) {
        String url = "https://api.example.com/create";
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<Object> entity = new HttpEntity<>(request, headers);
        return restTemplate.postForEntity(url, entity, String.class);
    }
}