笔者最初的一套代码模板

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.Map;

@Controller
@Slf4j
@RequestMapping("app/*")
public class AppController {

    @RequestMapping("list")
    public String list(Model model)
    {
        return "open/app/list";
    }

    @RequestMapping(name = "list", method = RequestMethod.POST)
    public String list(Model model, String keyword)
    {
        return "open/app/list";
    }

    @RequestMapping("create")
    public String create(Model model)
    {
        return "open/app/editor";
    }

    @RequestMapping(name = "view")
    public String view(Model model,Integer id)
    {
        return "open/app/editor";
    }

    @RequestMapping(name = "save", method = RequestMethod.POST)
    @ResponseBody
    public Map<String,Object> saveApp()
    {
        return null;
    }


    @RequestMapping(name = "update" ,method = RequestMethod.POST)
    @ResponseBody
    public Map<String,Object> update()
    {
        return null;
    }
}

注意标红加粗的地方。

然后又把这个文件复制了一遍重命名，为OrderController，然后就报错了。

最终发现原因是把@RequestMapping里面的参数填写错误，把name改成value

正确代码如下

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.Map;

@Controller
@Slf4j
@RequestMapping("app/*")
public class AppController {

    @RequestMapping("list")
    public String list(Model model)
    {
        return "open/app/list";
    }

    @RequestMapping(value = "list", method = RequestMethod.POST)
    public String list(Model model, String keyword)
    {
        return "open/app/list";
    }

    @RequestMapping("create")
    public String create(Model model)
    {
        return "open/app/editor";
    }

    @RequestMapping(value = "view")
    public String view(Model model,Integer id)
    {
        return "open/app/editor";
    }

    @RequestMapping(value = "save", method = RequestMethod.POST)
    @ResponseBody
    public Map<String,Object> saveApp()
    {
        return null;
    }


    @RequestMapping(value = "update" ,method = RequestMethod.POST)
    @ResponseBody
    public Map<String,Object> update()
    {
        return null;
    }
}