如何从 Spring Boot 提供静态 html？

我运行了 spring-boot-sample-web-static 项目here https://github.com/spring-projects/spring-boot/tree/1.5.x，对 pom 进行了此更改

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>

并添加此类以提供来自同一页面的重复页面index2.htmlstatic文件夹位置：

import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class Rester {

    @RequestMapping(value = "/rand", produces = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    private RandomObj jsonEndpoint() {
        return new RandomObj();
    }

    @RequestMapping(value = "/tw")
    public String somePg() {
        return "index2";
    }
}

json url 工作正常，但是当我尝试访问 localhost:8080/tw 时，我得到一个空白页面，并且控制台中出现此错误：

2017-02-22 15:37:22.076 ERROR 21494 --- [nio-8080-exec-9] o.s.boot.web.support.ErrorPageFilter     : Cannot forward to error page for request [/tw] as the response has already been committed. As a result, the response may have the wrong status code. If your application is running on WebSphere Application Server you may be able to resolve this problem by setting com.ibm.ws.webcontainer.invokeFlushAfterService to false

难道我做错了什么？

静态文件应该由资源提供，而不是由控制器提供。

Spring Boot 会自动添加位于以下位置的静态 Web 资源 以下任一目录：

/META-INF/resources/  
/resources/  
/static/  
/public/

refs:
https://spring.io/blog/2013/12/19/serving-static-web-content-with-spring-boot https://spring.io/blog/2013/12/19/serving-static-web-content-with-spring-boot
https://spring.io/guides/gs/serving-web-content/ https://spring.io/guides/gs/serving-web-content/