spring 中把接口作为参数调用

先看下面两段代码：

package com.example.webflux.handler;

import com.example.webflux.pojo.Greeting;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Mono;

@Component
public class GreetingHandler {

    public Mono<ServerResponse> hello(ServerRequest request) {
        return ServerResponse.ok()
                .contentType(MediaType.APPLICATION_JSON)
                .body(BodyInserters.fromValue(new Greeting("Hello Spring")));
    }
}

import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.RouterFunctions;
import org.springframework.web.reactive.function.server.ServerResponse;

import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
import static org.springframework.web.reactive.function.server.RequestPredicates.accept;

@Configuration(proxyBeanMethods = false)
@Import(TestRouter.class)
public class GreetingRouter {
    @Bean
    public RouterFunction<ServerResponse> route(GreetingHandler greetingHandler){
        return RouterFunctions.route(GET("/hello")
                .and(accept(MediaType.APPLICATION_JSON)),
                greetingHandler::hello
                );

    }
}

我一直想不明白为什么在route方法中传入一个接口类型的形参，就能调用相应的方法？后来听了黑马李老师的视屏后才明白原因

• GreetingHandler类因为标注了注解Component，所以在程序起动时会自动会向sprring容器中注入bean对象
• route方法上标注@Bean表示把返回对象注入到spring容器中，如果当方法中有形参时，就会默认进行自动装配注入

感谢李老师
视屏地址：https://www.toutiao.com/video/7088620870285034020/

来自为知笔记(Wiz)