Question

我使用start.spring.io初始化了spring boot项目，并添加了WEB，JPA，H2依赖项。

Pom文件

<?xml version="1.0" encoding="UTF-8"?>
<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.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>demo</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.10.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <!-- <scope>runtime</scope> -->
    </dependency>


</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

application.properties

spring.h2.console.enabled=true
security.basic.enabled=false

DemoApplication.java

@SpringBootApplication
public class DemoApplication {

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

UserController.java

@RestController
public class UserController {

    @GetMapping("/hello")
    public String hello() {
        return "Hello";
    }

控制台日志

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::       (v1.5.10.RELEASE)

2018-02-26 11:24:28.846  INFO 4792 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication on RAJAT-PC with PID 4792 (C:\Users\devra\Downloads\Compressed\demo\target\classes started by rajat in C:\Users\devra\Downloads\Compressed\demo)
2018-02-26 11:24:28.855  INFO 4792 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
2018-02-26 11:24:29.018  INFO 4792 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6b67034: startup date [Mon Feb 26 11:24:29 IST 2018]; root of context hierarchy
2018-02-26 11:24:30.894  INFO 4792 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$fa7e8c5a] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2018-02-26 11:24:31.720  INFO 4792 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2018-02-26 11:24:31.737  INFO 4792 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-02-26 11:24:31.740  INFO 4792 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.27
2018-02-26 11:24:31.969  INFO 4792 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-02-26 11:24:31.970  INFO 4792 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 2957 ms
2018-02-26 11:24:32.307  INFO 4792 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-02-26 11:24:32.308  INFO 4792 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-02-26 11:24:32.309  INFO 4792 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-02-26 11:24:32.309  INFO 4792 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-02-26 11:24:32.310  INFO 4792 --- [ost-startStop-1] .s.DelegatingFilterProxyRegistrationBean : Mapping filter: 'springSecurityFilterChain' to: [/*]
2018-02-26 11:24:32.311  INFO 4792 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2018-02-26 11:24:32.313  INFO 4792 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'webServlet' to [/h2-console/*]
2018-02-26 11:24:33.004  INFO 4792 --- [           main] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'default'
2018-02-26 11:24:33.038  INFO 4792 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [
    name: default
    ...]
2018-02-26 11:24:33.196  INFO 4792 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate Core {5.0.12.Final}
2018-02-26 11:24:33.199  INFO 4792 --- [           main] org.hibernate.cfg.Environment            : HHH000206: hibernate.properties not found
2018-02-26 11:24:33.202  INFO 4792 --- [           main] org.hibernate.cfg.Environment            : HHH000021: Bytecode provider name : javassist
2018-02-26 11:24:33.266  INFO 4792 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
2018-02-26 11:24:33.517  INFO 4792 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2018-02-26 11:24:33.807  INFO 4792 --- [           main] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000227: Running hbm2ddl schema export
2018-02-26 11:24:33.816  INFO 4792 --- [           main] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000230: Schema export complete
2018-02-26 11:24:33.859  INFO 4792 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2018-02-26 11:24:34.365  INFO 4792 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6b67034: startup date [Mon Feb 26 11:24:29 IST 2018]; root of context hierarchy
2018-02-26 11:24:34.506  INFO 4792 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-02-26 11:24:34.508  INFO 4792 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-02-26 11:24:34.568  INFO 4792 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-02-26 11:24:34.569  INFO 4792 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-02-26 11:24:34.663  INFO 4792 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-02-26 11:24:35.147  INFO 4792 --- [           main] b.a.s.AuthenticationManagerConfiguration : 

Using default security password: dd5212d7-4de1-4fee-9f6b-f5cd888f2f17

2018-02-26 11:24:35.222  INFO 4792 --- [           main] o.s.s.web.DefaultSecurityFilterChain     : Creating filter chain: OrRequestMatcher [requestMatchers=[Ant [pattern='/css/**'], Ant [pattern='/js/**'], Ant [pattern='/images/**'], Ant [pattern='/webjars/**'], Ant [pattern='/**/favicon.ico'], Ant [pattern='/error']]], []
2018-02-26 11:24:35.334  INFO 4792 --- [           main] o.s.s.web.DefaultSecurityFilterChain     : Creating filter chain: org.springframework.boot.autoconfigure.security.SpringBootWebSecurityConfiguration$ApplicationNoWebSecurityConfigurerAdapter$1@11c713b7, [org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter@2251b3bc, org.springframework.security.web.context.SecurityContextPersistenceFilter@602f8f94, org.springframework.security.web.header.HeaderWriterFilter@2785db06, org.springframework.security.web.csrf.CsrfFilter@603cabc4, org.springframework.security.web.authentication.logout.LogoutFilter@7a9ceddf, org.springframework.security.web.savedrequest.RequestCacheAwareFilter@4dfe8b37, org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter@7e64c1a9, org.springframework.security.web.authentication.AnonymousAuthenticationFilter@3fbe503c, org.springframework.security.web.session.SessionManagementFilter@715a70e9, org.springframework.security.web.access.ExceptionTranslationFilter@1cc8416a]
2018-02-26 11:24:35.552  INFO 4792 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-02-26 11:24:35.652  INFO 4792 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2018-02-26 11:24:35.670  INFO 4792 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 7.302 seconds (JVM running for 7.824)

你可以看到spring没有映射/hello url

Answer 1

Spring参考文档说 - 通常建议您将主应用程序类放在其他类（如

）之上的根包中

com
 +- example
     +- myproject
         +- Application.java
         |
         +- domain
         |   +- Customer.java
         |   +- CustomerRepository.java
         |
         +- service
         |   +- CustomerService.java
         |
         +- web
             +- CustomerController.java

有关更多信息，请参阅此链接：

https://docs.spring.io/spring-boot/docs/current/reference/html/using-boot-structuring-your-code.html

Answer 2

考虑到其他答案并不能解释为什么它没有按预期工作，这就是原因。

Spring使用组件扫描来查找符合条件的bean（@Repository，@Service，@Component，@Controller，...）。这通常通过使用@ComponentScan注释来完成。这在core docs：

中有解释

要自动检测这些类并注册相应的bean，您需要将@ComponentScan添加到@Configuration类，其中basePackages属性是这两个类的公共父包。（或者，您可以指定包含每个类的父包的逗号/分号/空格分隔列表。）

Spring Boot默认只扫描主类的同一个包（包括子包）中的组件。这是因为@SpringBootApplication注释默认包含@ComponentScan，如Spring boot docs中所述：

@SpringBootApplication注释相当于使用@Configuration，@EnableAutoConfiguration和@ComponentScan及其默认属性

如果您希望Spring自动检测您的控制器，您有三种选择：

将控制器移至com.example.demo包。这是根据Spring boot documentation建议的方法。

通过添加controller注释来告诉Spring查看@ComponentScan包：

@SpringBootApplication
@ComponentScan({"com.example.demo", "controller"}) // Add this
public class DemoApplication {
    // ...
}

通过配置controller的{{1}}属性来告诉Spring查看scanBasePackages包：
```
@SpringBootApplication
```

休息控制器不工作

2 个答案: