微服务 SpringBoot 3.0 内置声明式HTTP客户端与注册中心服务绑定_@getexchange

1 SpringBoot3.0 新特性

SpringBoot3.0 正式版发布后，最低支持JDK17并支持使用 GraalVM 将 Spring 的应用程序编译成本地可执行的镜像文件以及Http interface内置声明式的HTTP客户端等许多新特性。

2 声明式客户端使用

2.1 引入依赖

<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>
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2.2 创建 Http interface 类型

在接口类上添加注解 @HttpExchange 声明此类是 http interface 端点，并使用如下注解增加方法接口
@GetExchange: for HTTP GET requests.
@PostExchange: for HTTP POST requests.
@PutExchange: for HTTP PUT requests.
@DeleteExchange: for HTTP DELETE requests.
@PatchExchange: for HTTP PATCH requests.

@HttpExchange
public interface RemoteDemoApi {

    @GetExchange("/demo")
    String demo();

}
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2.3 注入声明式客户端

通过HttpServiceProxyFactory 携带目标接口的 BaseUrl 实现 webclient 和 http interface 的关联，使用ReactorLoadBalancerExchangeFilterFunction 负载均衡通过服务名从注册中心获取地址。

@Autowired
private ReactorLoadBalancerExchangeFilterFunction reactorLoadBalancerExchangeFilterFunction;

@Bean
public RemoteDemoApi remoteDemoLoadBalancer() {
    WebClient client = WebClient.builder().filter(reactorLoadBalancerExchangeFilterFunction).baseUrl("http://UpmsService/").build();
    HttpServiceProxyFactory factory = HttpServiceProxyFactory.builder(WebClientAdapter.forClient(client)).build();
    return factory.createClient(RemoteDemoApi.class);
}

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2.4 测试调用

@RestController
@RequestMapping("/test")
public class TestController {
	private final RemoteDemoApi remoteDemoApi;
	
	public TestController(RemoteDemoApi remoteDemoApi) {
	    this.remoteDemoApi = remoteDemoApi;
	}
	
	@GetMapping
	public String demo() {
	    return remoteDemoApi.demo();
	}
}
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