java - Spring getBeanNamesForType 工作不正常

Question

我有简单的上下文配置

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.core.ResolvableType;

import java.util.Arrays;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(DemoApplication.class, args);

        String[] namesForType = ctx.getBeanNamesForType(ResolvableType.forClassWithGenerics(Transformer.class, Integer.class, String.class));

        System.out.println("namesForType = " + Arrays.toString(namesForType));
    }

    @Bean
    public Transformer<Integer, String> stringTransformer() {
        return new Transformer<Integer, String>();
    }
}

和简单的类

package com.example;

public class Transformer<F, T> {

    T transform(F from) {
        return null;
    }
}

当我启动应用程序时，输出是 namesForType = []

如果将 bean 的创建更改为单独的类，例如

    @Bean
    public Transformer<Integer, String> stringTransformer() {
        return new Transformer<Integer, String>(){};
    }

输出为 namesForType = [stringTransformer]

Answer 1

这是正确的行为。在使用 @Bean 注释之前，它不会在 spring 上下文中被拾取。