第一种：实现ErrorPageRegistrar

@Configuration
public class ErrorConfigurar implements ErrorPageRegistrar {
 
    @Override
    public void registerErrorPages(ErrorPageRegistry registry) {
        ErrorPage[] errorPages = new ErrorPage[2];
        errorPages[0] = new ErrorPage(HttpStatus.NOT_FOUND, "/404.html");
        errorPages[1] = new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/500.html");
 
        registry.addErrorPages(errorPages);
    }
}

第二种：SpringBoot2.0之前的写法

@Bean
    public EmbeddedServletContainerCustomizer containerCustomizer() {
        return new EmbeddedServletContainerCustomizer() {
            @Override
            public void customize(ConfigurableEmbeddedServletContainer container) {
                ErrorPage errorPage404 = new ErrorPage(HttpStatus.NOT_FOUND, "404.html");
                container.addErrorPages(errorPage404);
            }
        };
    }

第三种：SpringBoot2.0之后的写法

@Configuration
public class ErrorPageConfig {
    /**
     * SpringBoot2.0以上版本WebServerFactoryCustomizer代替之前版本的EmbeddedWebServerFactoryCustomizerAutoConfiguration
     *
     * @return
     */
 
    //@Bean必须加上
    @Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> webServerFactoryCustomizer() {
//        //第一种：java7 常规写法
//        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>() {
//            @Override
//            public void customize(ConfigurableWebServerFactory factory) {
//                ErrorPage errorPage404 = new ErrorPage(HttpStatus.NOT_FOUND, "/404.html");
//                factory.addErrorPages(errorPage404);
//            }
//        };
        //第二种写法：java8 lambda写法
        return (factory -> {
            ErrorPage errorPage404 = new ErrorPage(HttpStatus.NOT_FOUND, "/404.html");
            factory.addErrorPages(errorPage404);
        });
    }
 
}