原理

Spring的HTTP 服务接口是一个带有@HttpExchange方法的 Java 接口，它支持的支持的注解类型有：

• @HttpExchange：是用于指定 HTTP 端点的通用注释。在接口级别使用时，它适用于所有方法。
• @GetExchange：为 HTTP GET请求指定@HttpExchange。
• @PostExchange：为 HTTP POST请求指定@HttpExchange。
• @PutExchange：为 HTTP PUT请求指定@HttpExchange。
• @DeleteExchange：为 HTTP DELETE请求指定@HttpExchange。
• @PatchExchange：为 HTTP PATCH请求指定@HttpExchange。

示例：访问远程接口https://api.chucknorris.io/jokes/random

第一步：添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

第二步：配置类

@Configuration
public class HttpConfig {
    @Bean
    public WebClient webClient() {
        return WebClient.builder()
                .baseUrl("https://api.chucknorris.io/")
                .build();
    }

    @Bean
    public ChuckNorrisService postClient(WebClient webClient) {
        HttpServiceProxyFactory httpServiceProxyFactory =
                HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient))
                        .build();
        return httpServiceProxyFactory.createClient(ChuckNorrisService.class);
    }
}

第三步：远程Service

@HttpExchange(url = "/jokes")
public interface ChuckNorrisService {

    //https://api.chucknorris.io/jokes/random
    @HttpExchange(url = "/random", method = "GET")
        //@GetExchange("/reduct")
    String reduct();

}

第四步：Controller中使用远程Service

@RestController
@RequestMapping("/order")
public class OrderController {

    @Resource
    private ChuckNorrisService chuckNorrisService;

    @GetMapping("/create")
    public String create() {
        System.out.println("下单成功！");

        //扣除库存
        String stockMsg = chuckNorrisService.reduct();

        return "order add success -- " + stockMsg;
    }

}

第五步：测试