java - 使用 IntelliJ 将 Java lambda 转换为 Kotlin Lambda 生成语法错误

Question

我有一个 Java 类配置 Spring Boot 2.0.6 的嵌入 tomcat 以使用 HTTP2 协议(protocol):

package com.talleres.paco.mako.config;

import org.apache.catalina.connector.Connector;
import org.apache.coyote.http2.Http2Protocol;
import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class TomcatHttp2Config {
    @Bean
    public ConfigurableServletWebServerFactory tomcatCustomizer() {
        TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
        factory.addConnectorCustomizers((Connector connector) -> {
            connector.addUpgradeProtocol(new Http2Protocol());
        });
        return factory;
    }
}

当我使用 IntelliJ 将此片段代码转换为 Kotlin 时，出现编译错误。这是 IntelliJ 返回的 Kotlin 代码:

package com.talleres.paco.mako.config

import org.apache.catalina.connector.Connector
import org.apache.coyote.http2.Http2Protocol
import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration

@Configuration
class TomcatHttp2Config {
    @Bean
    fun tomcatCustomizer(): ConfigurableServletWebServerFactory {
        val factory = TomcatServletWebServerFactory()
        factory.addConnectorCustomizers({ connector: Connector -> connector.addUpgradeProtocol(Http2Protocol()) })
        return factory
    }
}

我得到这个错误:

Type mismatch.
Required:
TomcatConnectorCustomizer!
Found:
(Connector) → Unit

在出现 lambda 的行:

    factory.addConnectorCustomizers({ connector: Connector -> connector.addUpgradeProtocol(Http2Protocol()) })

我如何将上面的 Java 代码翻译成 Kotlin。提前致谢。

Answer 1

你可以看看SAM conversions对于 Kotlin。

如果由于某种原因，带有该方法的版本不起作用

factory.addConnectorCustomizers { it.addUpgradeProtocol(Http2Protocol()) }

您可以尝试轻松地实现 Java 接口(interface)

factory.addConnectorCustomizers(TomcatConnectorCustomizer { it.addUpgradeProtocol(Http2Protocol()) })