RestController 返回 404 (Spring Boot 2.3.7)

Question

我用 RestContoller 编写了一个 Spring Boot 应用程序。 但是当我在浏览器中点击 URL 时，我收到 404 错误。 但我不确定我做错了什么。 一切似乎都是正确的。 我的控制器类如下所示：

package com.gtt.wcas.device.root;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class DeviceConnectionController {

    Logger logger = LoggerFactory.getLogger(DeviceConnectionController.class.getName());

    .
    .
    .
    // Lots of variables
    .
    .
    .


    @RequestMapping(value = "/deviceConnection", method = RequestMethod.GET)
    @ResponseBody
    public ResponseEntity<String> deviceConnection(@RequestParam(value = "verify", defaultValue = "false") String verify) {

        .
        .
        //Method body.... lots of code...
        .
        .

        return new ResponseEntity<String>(HttpStatus.OK);
    }


    @RequestMapping(value = "/error", method = RequestMethod.GET)
    public ResponseEntity<String> error () {
        return new ResponseEntity<String>(HttpStatus.INTERNAL_SERVER_ERROR);
    }


    .
    .
    .
    // Lots of other helper methods.
    .
    .
    .
}

我的主要课程是这样的：

package com.gtt.wcas.device.root;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages = "com.gtt.wcas.device.details")
@ConfigurationPropertiesScan(basePackages = "com.gtt.wcas.device.configuration")
@EntityScan(basePackages = "com.gtt.wcas.device.db.jpa")
public class wcasDeviceConnectionApplication {

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

我的应用程序属性是：

#datasource configurations
spring.datasource.url=MY DB URL
spring.datasource.username=MY DB USERNAME
spring.datasource.password=MY DB PASSWORD
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

# Enabling H2 Console
spring.h2.console.enabled=true
# Custom H2 Console URL
spring.h2.console.path=/h2-console

# DDL generation
spring.jpa.generate-ddl=true

logging.level.ch.qos.logback==DEBUG
spring.devtools.restart.enabled=true
debug=true

当我在浏览器上输入http://localhost:8080/deviceConnection?verify=true时，我会在日志中看到：

2022-06-16 19:00:00.078 DEBUG 19444 --- [nio-8080-exec-4] o.s.web.servlet.DispatcherServlet        : GET "/deviceConnection?verify=true", parameters={masked}
2022-06-16 19:00:00.079 DEBUG 19444 --- [nio-8080-exec-4] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [classpath [META-INF/resources/], classpath [resources/], classpath [static/], classpath [public/], ServletContext [/]]
2022-06-16 19:00:00.082 DEBUG 19444 --- [nio-8080-exec-4] o.s.w.s.r.ResourceHttpRequestHandler     : Resource not found
2022-06-16 19:00:00.082 DEBUG 19444 --- [nio-8080-exec-4] o.s.web.servlet.DispatcherServlet        : Completed 404 NOT_FOUND
2022-06-16 19:00:00.082 DEBUG 19444 --- [nio-8080-exec-4] o.s.web.servlet.DispatcherServlet        : "ERROR" dispatch for GET "/error?verify=true", parameters={masked}
2022-06-16 19:00:00.083 DEBUG 19444 --- [nio-8080-exec-4] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#errorHtml(HttpServletRequest, HttpServletResponse)
2022-06-16 19:00:00.096 DEBUG 19444 --- [nio-8080-exec-4] o.s.w.s.v.ContentNegotiatingViewResolver : Selected 'text/html' given [text/html, text/html;q=0.8]
2022-06-16 19:00:00.097 DEBUG 19444 --- [nio-8080-exec-4] o.s.web.servlet.DispatcherServlet        : Exiting from "ERROR" dispatch, status 404

你能告诉我我做错了什么吗？ 任何帮助深表感谢。

Answer 1

您的控制器位于com.gtt.wcas.device.root包中，但您设置@ComponentScan(basePackages = "com.gtt.wcas.device.details") 。

Spring 永远不会拾取您的控制器。 将其移动到另一个包或更改您的组件扫描。

Answer 2

您可以在@ComponentScan中添加com.gtt.wcas.device.root吗？ 并检查，

我在 Spring boot 中观察到了这个问题，有时，如果您的 Controller 位于不同的包（源包除外）并且未明确扫描，它不会识别端点。

此外，您不需要在方法定义之上使用@ResponseBody ，因为@RestController已经具有该定义！