java spring如何实现代码干净的写法？

比如

package com.demo.controller;

public class DemoController {

    public Object saveWithPost() {
        return null;
    }

    public Object listWithGet() {
        return null;
    }

}

其实相当于

package com.demo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("demo")
public class DemoController {

    @PostMapping(value = "save")
    public Object saveWithPost() {
        return null;
    }

    @GetMapping(value = "list")
    public Object listWithGet() {
        return null;
    }

}

代码不需要手动处理就可以执行。