This is the sixth day of my participation in the August Text Challenge.More challenges in August

The feed

Because the project needs to display other logs in the server disk, so we plan to use Spring Boot static resource mapping mode to display files on the page, convenient to download problems just can learn some wave of partial source code

Code configuration

` ` `package com.hgf.boot.config;

import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import org.springframework.boot.autoconfigure.jackson.Jackson2ObjectMapperBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/** * Spring MVC configuration ** /
@Configuration
public class SpringMvcConfiguration implements WebMvcConfigurer {

    /** * Static resource mapping */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
       
// Note that addResourceLocations must end with /
registry.addResourceHandler("/work_doc/**").addResourceLocations("file:/Users/hans/work_space/work/work/"); }}Copy the code

Source code analysis

In fact, the whole link is divided into two parts

• How do I fit request/work_doc/**Request to the folder/Users/hans/work_space/work/work/Mapping preservation
• If you visit

Mapping preservation

ResourceHandlerRegistration#addResourceLocations

public ResourceHandlerRegistration addResourceLocations(String... resourceLocations) {
   this.locationValues.addAll(Arrays.asList(resourceLocations));
   return this;
}
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At this time on this. Where locationValues is called, ResourceHandlerRegistration# getRequestHandler

protected ResourceHttpRequestHandler getRequestHandler(a) {
   ResourceHttpRequestHandler handler = new ResourceHttpRequestHandler();
   if (this.resourceChainRegistration ! =null) {
      handler.setResourceResolvers(this.resourceChainRegistration.getResourceResolvers());
      handler.setResourceTransformers(this.resourceChainRegistration.getResourceTransformers());
   }
   handler.setLocationValues(this.locationValues);
   if (this.cacheControl ! =null) {
      handler.setCacheControl(this.cacheControl);
   }
   else if (this.cachePeriod ! =null) {
      handler.setCacheSeconds(this.cachePeriod);
   }
   return handler;
}
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Step by step, you can see the following call link

WebMvcConfigurationSupport#resourceHandlerMapping
ResourceHandlerRegistry#getHandlerMapping
ResourceHandlerRegistration#getRequestHandler
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/ / register handlerMapping
@Bean
public HandlerMapping resourceHandlerMapping(a) {
   Assert.state(this.applicationContext ! =null."No ApplicationContext set");
   Assert.state(this.servletContext ! =null."No ServletContext set");

   ResourceHandlerRegistry registry = new ResourceHandlerRegistry(this.applicationContext,
         this.servletContext, mvcContentNegotiationManager(), mvcUrlPathHelper());
   addResourceHandlers(registry);

   AbstractHandlerMapping handlerMapping = registry.getHandlerMapping();
   if(handlerMapping ! =null) {
      handlerMapping.setPathMatcher(mvcPathMatcher());
      handlerMapping.setUrlPathHelper(mvcUrlPathHelper());
      handlerMapping.setInterceptors(getInterceptors());
      handlerMapping.setCorsConfigurations(getCorsConfigurations());
   }
   else {
      handlerMapping = new EmptyHandlerMapping();
   }
   return handlerMapping;
}
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If you visit

The Spring MVC flow network diagram is as follows

Combining the registration to the spring container BeanHandlerMapping, can probably guess the process org. Springframework. Web. Servlet. DispatcherServlet# doDispatch (omitted)

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {...try {
      ModelAndView mv = null;
      Exception dispatchException = null;

      try {

         // Get the processor mapper
         mappedHandler = getHandler(processedRequest);
         if (mappedHandler == null) {
            noHandlerFound(processedRequest, response);
            return;
         }

         // Get the processor adapter
         HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

         
         // Call handler (handle request details source code)mv = ha.handle(processedRequest, response, mappedHandler.getHandler()); . }// Render returnsprocessDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException); }... }Copy the code

The detailed call stack is shown

getResource:186, PathResourceResolver (org.springframework.web.servlet.resource)
getResource:157, PathResourceResolver (org.springframework.web.servlet.resource)
resolveResourceInternal:136, PathResourceResolver (org.springframework.web.servlet.resource)
resolveResource:48, AbstractResourceResolver (org.springframework.web.servlet.resource)
resolveResource:61, DefaultResourceResolverChain (org.springframework.web.servlet.resource)
getResource:529, ResourceHttpRequestHandler (org.springframework.web.servlet.resource)
handleRequest:439, ResourceHttpRequestHandler (org.springframework.web.servlet.resource)
handle:53, HttpRequestHandlerAdapter (org.springframework.web.servlet.mvc)
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If there is a problem in the project, follow this process step by step to find the problem