spring - 构建 Spring MVC 应用程序， Controller "Cannot find symbol"模型

Question

我首先使用 gradle bootRun 和以下 Controller 类成功构建了我的 Spring MVC 项目:

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

@Controller
public class HelloController {

  @RequestMapping("/")
  public String hello() {
    return "resultPage";
  }
}

然后我将其更改为将数据传递给我的 View 类:

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

@Controller
public class HelloController {

  @RequestMapping("/")
  public String hello(Model model) {
    model.addAttribute("message", "Hello from the controller");
    return "resultPage";
  }
}

当我现在构建我的项目时，出现以下错误:

HelloController.java:13: error: cannot find symbol
    public String hello(Model model) {
                        ^
  symbol:   class Model
  location: class HelloController
1 error
:compileJava FAILED

FAILURE: Build failed with an exception.

知道我做错了什么吗？

Answer 1

我发现了问题。

如果我们希望 DispatcherServlet 将 Model 注入(inject)到函数中，我们应该做的一件事就是导入 Model 类。

import org.springframework.ui.Model;

所以，我将我的 Controller 类更改为以下内容并且它起作用了!

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.ui.Model;

@Controller
public class HelloController {

  @RequestMapping("/")
  public String hello(Model model) {
    model.addAttribute("message", "Hello from the controller");
    return "resultPage";
  }
}