Rest Controller 无法识别 Spring Boot App 中的 GET 请求

我正在尝试使用 Spring Boot 实现简单的演示 MVC 应用程序，但在执行应用程序时出现 404 错误。 uri 是“ http://localhost:8080/ ”，用于显示名为 circle 的表中的所有行。

春季启动：1.3.3.RELEASE
Java 版本：1.8.0_65
数据库：Apache Derby 10.12.1.1

Maven Java 项目：

应用.java

 package com.nomad.dubbed.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application  {

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

}

CircleController.java

 package com.nomad.dubbed.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.nomad.dubbed.dao.CircleService;
import com.nomad.dubbed.model.Circle;

@RestController
@RequestMapping("/")
public class CircleController {
    @Autowired
    private CircleService circleService;

    @RequestMapping(method=RequestMethod.GET)
    public List<Circle> getAll() {
        return circleService.getAll();
    }

}

CircleRepository.java

 package com.nomad.dubbed.dao;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.nomad.dubbed.model.Circle;

@Repository
public interface CircleRepository extends JpaRepository<Circle, Integer> {

}

CircleService.java

 package com.nomad.dubbed.dao;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import com.nomad.dubbed.model.Circle;

@Service
public class CircleService {
    @Autowired
    private CircleRepository circleRepository;

    @Transactional(propagation=Propagation.REQUIRED)
    public List<Circle> getAll(){
        return circleRepository.findAll();
    }

}

圈子.java

 package com.nomad.dubbed.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="circle")
public class Circle {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private int id;
    private String name;

    public Circle(int id, String name) {
        super();
        this.id = id;
        this.name = name;
    }

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

}

应用程序.properties

 spring.datasource.url=jdbc:derby://localhost:1527/db
spring.datasource.driverClassName=org.apache.derby.jdbc.ClientDriver

logging.level.org.springframework.web:DEBUG
logging.level.org.hibernate:DEBUG

pom.xml

 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.nomad.dubbed</groupId>
  <artifactId>spring-boot-mvc</artifactId>
  <version>0.0.1-SNAPSHOT</version>

    <properties>
        <derby-client.version>10.11.1.1</derby-client.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.3.RELEASE</version>
        <relativePath />
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-remote-shell</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derbyclient</artifactId>
            <version>${derby-client.version}</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <finalName>spring-boot-mvc</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

数据库启动并运行，表圈内有5行：

默认 uri（/beans、/health..）工作正常，但无法识别已实现的控制器。控制台中没有显示此类错误，下面是我发送请求后打印在控制台中的日志转储。

 2016-05-03 14:17:26.594 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : DispatcherServlet with name 'dispatcherServlet' processing GET request for [/]
2016-05-03 14:17:26.596 DEBUG 659 --- [nio-8080-exec-3] s.w.s.m.m.a.RequestMappingHandlerMapping : Looking up handler method for path /
2016-05-03 14:17:26.596 DEBUG 659 --- [nio-8080-exec-3] s.w.s.m.m.a.RequestMappingHandlerMapping : Did not find handler method for [/]
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.w.s.handler.SimpleUrlHandlerMapping  : Matching patterns for request [/] are [/**]
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.w.s.handler.SimpleUrlHandlerMapping  : URI Template variables for request [/] are {}
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapping [/] to HandlerExecutionChain with handler [ResourceHttpRequestHandler [locations=[ServletContext resource [/], class path resource [META-INF/resources/], class path resource [resources/], class path resource [static/], class path resource [public/]], resolvers=[org.springframework.web.servlet.resource.PathResourceResolver@6c13019c]]] and 1 interceptor
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Last-Modified value for [/] is: -1
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Null ModelAndView returned to DispatcherServlet with name 'dispatcherServlet': assuming HandlerAdapter completed request handling
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Successfully completed request
2016-05-03 14:17:26.597 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : DispatcherServlet with name 'dispatcherServlet' processing GET request for [/error]
2016-05-03 14:17:26.600 DEBUG 659 --- [nio-8080-exec-3] s.w.s.m.m.a.RequestMappingHandlerMapping : Looking up handler method for path /error
2016-05-03 14:17:26.600 DEBUG 659 --- [nio-8080-exec-3] s.w.s.m.m.a.RequestMappingHandlerMapping : Returning handler method [public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)]
2016-05-03 14:17:26.600 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Last-Modified value for [/error] is: -1
2016-05-03 14:17:26.601 DEBUG 659 --- [nio-8080-exec-3] o.s.w.s.v.ContentNegotiatingViewResolver : Requested media types are [text/html, text/html;q=0.8] based on Accept header types and producible media types [text/html])
2016-05-03 14:17:26.601 DEBUG 659 --- [nio-8080-exec-3] o.s.w.s.v.ContentNegotiatingViewResolver : Returning [org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView@2f5f8d71] based on requested media type 'text/html'
2016-05-03 14:17:26.601 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Rendering view [org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView@2f5f8d71] in DispatcherServlet with name 'dispatcherServlet'
2016-05-03 14:17:26.601 DEBUG 659 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Successfully completed request

原文由 gkc123 发布，翻译遵循 CC BY-SA 4.0 许可协议

我们不应将 @ComponentScan 注释与 @SpringBootApplication 一起使用，因为这不是正确的做法。 @SpringBootApplication is a combination of 3 annotations: @ComponentScan , @EnableAutoConfiguration and @Configuration .

具有 @SpringBootApplication 注释的主类应该在父/超级包中。

EG com.spring.learning.service 566D0D815E7245AE7F3242B63AAFEACC com.spring.learning 是父母套餐，其子女是 com.spring.learning.controller com.spring.learning.pojo

因此它扫描它的包和子包。

这是最佳实践——项目布局或结构是 Spring Boot 中的一个突出概念。

原文由 Ankita Chaturvedi 发布，翻译遵循 CC BY-SA 4.0 许可协议

Rest Controller 无法识别 Spring Boot App 中的 GET 请求

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