java - Spring怎么知道HttpServletRequest类的存在的？

Question

package test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

public class Test {
    /**
     * @param args
     */
    public static void main(String[] args) {
        ApplicationContext ac=new FileSystemXmlApplicationContext("D:\\spring.xml");
    }
}
   

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'hqController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.servlet.http.HttpServletRequest gnnt.hq.site.controller.HqController.request; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [javax.servlet.http.HttpServletRequest] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    at org.springframework.context.support.FileSystemXmlApplicationContext.<init>(FileSystemXmlApplicationContext.java:140)
    at org.springframework.context.support.FileSystemXmlApplicationContext.<init>(FileSystemXmlApplicationContext.java:84)
    at test.Test.main(Test.java:14)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.servlet.http.HttpServletRequest gnnt.hq.site.controller.HqController.request; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [javax.servlet.http.HttpServletRequest] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 13 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [javax.servlet.http.HttpServletRequest] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1100)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:960)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)

@Controller
public class HqController
{
    @Autowired
    @Qualifier("hqService")
    private IGetHqService service;
    @Autowired  
    private  HttpServletRequest request;

以web项目在tomcat中运行没有问题，直接获取spring容器的时候就报错了。原因是在给HqController注入HttpServletRequest类的时候失败了。那么为什么部署在tomcat中启动就能注入成功呢？
以<bean>和注解的形式让spring创造bean，为什么部署在tomcat中启动时，Spring就会HttpServletRequest用来注入了呢？

Answer 1

Oleh kerana tomcat, sebagai bekas Servlet, mempunyai pelaksanaan HttpServletRequest dan HttpServletResponse, dipanggil org.apache.catalina.connector.RequestFacade dan org.apache.catalina.connector.ResponseFacade. Jika anda ingin menjalankannya secara tempatan, anda perlu menambah kebergantungan kontena terbina dalam seperti tomcat atau jeti.

Answer 2

Objek berkaitan servlet dicipta oleh bekas