1. RestTemplate

• 1. 注册Bean

@SpringBootApplication
public class CartServiceApplication {public static void main(String[] args) {SpringApplication.run(CartServiceApplication.class, args);System.out.println("cart启动成功");}@Beanpublic RestTemplate restTemplate() {return new RestTemplate();}}

• 2. 在代码中引入Bean

// 推荐使用构造函数注入, 使用lombook的@RequiredArgsConstructor进行注入private final RestTemplate restTemplate;

• 3. 远程调用

// 1.获取商品idSet<Long> itemIds = vos.stream().map(CartVO::getItemId).collect(Collectors.toSet());// 2.查询商品ResponseEntity<List<ItemDTO>> response = restTemplate.exchange("http://localhost:8081/items?ids={ids}",HttpMethod.GET,null,new ParameterizedTypeReference<List<ItemDTO>>() {},Map.of("ids", CollUtil.join(itemIds, ",")));if (!response.getStatusCode().is2xxSuccessful()) {return;}List<ItemDTO> items = response.getBody();