java运算符的含义" - >" [英] Meaning of java operator "->"

问题描述

java运算符 - >的含义是什么，如下面的代码所示，取自SpringBoot应用程序的初始化：

What is the meaning of the java operator "->" like in the following code, taken from the initialization of a SpringBoot application:

    @Bean
    public EmbeddedServletContainerCustomizer containerCustomizer() {

        return (container -> {
            ErrorPage error401Page = new ErrorPage(HttpStatus.UNAUTHORIZED, "/401.html");
            ErrorPage error403Page = new ErrorPage(HttpStatus.FORBIDDEN, "/403.html");
            ErrorPage error404Page = new ErrorPage(HttpStatus.NOT_FOUND, "/404.html");
            ErrorPage error500Page = new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/500.html");

            container.addErrorPages(error401Page, error403Page, error404Page, error500Page);
        });
    }

推荐答案

这是针对 lambda表达式，这是Java 8中首次引入的语言特性。基本上这个是一个内联匿名函数，它将 container 作为参数。通常lambdas返回值，但在这里它看起来只是执行调用 addErrorPages 到容器的副作用 。没有为容器指定类型，因为Java会从上下文中直接显示它。

This is for a lambda expression, a language feature first introduced in Java 8. Basically this is an inline anonymous function that takes container as a parameter. Usually lambdas return values but here it looks like it is just carrying out the "side effect" of calling addErrorPages to container. There is no type specified for container as Java intuits it from the context.

Lambda表达式不仅仅是一种语言功能，它们也是计算机科学和函数式编程的整个领域。描述它们的好SO帖子是这里。

Lambda expressions are more than a language feature, they are also a whole area of computer science and functional programming. A good SO post describing them is here.

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