java - 简单 Spring 应用程序中的依赖注入(inject)不起作用(将服务注入(inject) Controller 变量)

Question

我有一个非常简单的项目。

它有主类:

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@ComponentScan
@EnableAutoConfiguration
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

Controller :

package com.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
public class Controller {

    @Autowired
    MyService myService;

    @RequestMapping("/application")
    public String getApp(ModelMap model) {
        return "application";
    }

    @RequestMapping("/application/home")
    public String do(@RequestParam(value="input", required=false) String input, ModelMap model) {
        if (!StringUtils.isEmpty(input)) {
            model.addAttribute(INPUT_ATT, input);
            model.addAttribute(OUTPUT_ATT, myService.do(input));
        }
        return "home";
    }

}

还有一个服务(接口(interface)、实现):

package com.example;

public interface MyService {

    String do(String input);
}

.

package com.example;

import org.springframework.stereotype.Service;

@Service
public class MyServiceImpl implements MyService {

    @Override
    public String do(String input) {
        return "result";
    }

}

不幸的是，MyServiceImpl 的实例没有被注入(inject)到 Controller 类中的 myService 变量中。

我应该怎么做才能解决这个问题？

关于，

Answer 1

您的代码未编译，因为“do”是关键字。但除此之外，您的代码应该没问题。我也尝试使用 SpringBoot 稍作修改

申请

@SpringBootApplication
public class Application {

    /**
     * Run the Web Application using built-in Tomcat server.
     * This is used for testing only
     * @param args
     */
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Controller

@RestController
public class HelloworldController {

    @Autowired
    private IHelloworldHelper helper;

    @RequestMapping("/hello")
    public Helloworld hello(String name) {
        return new Helloworld(1, helper.doAction(name));
    }
}

助手

@Service
public class HelloworldHelper implements IHelloworldHelper {

    @Override
    public String doAction(String name) {
        return String.format("Hi %s!", name);
    }
}

public interface IHelloworldHelper {

    public String doAction(String name);
}

模型

public class Helloworld {

    private long id;
    private String content;

    public Helloworld(long id, String content) {
        this.id = id;
        this.content = content;
    }

    public long getId() {
        return id;
    }

    public String getContent() {
        return content;
    }
}