一、靜態資源映射
通過之前自動裝配原理源碼的分析思路，現在可以很容易就鎖定對應SpringMVC相關的配置類。,找到MVC自動配置類中的適配器中的增加資源的處理器。
訪問路徑會被映射爲對應路徑下的資源，SpringBoot牛逼！
public void addResourceHandlers(ResourceHandlerRegistry registry) {
if (!this.resourceProperties.isAddMappings()) {
logger.debug("Default resource handling disabled");
} else {
Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
if (!registry.hasMappingForPattern("/webjars/**")) {
//說明/webjars/**路徑下的資源會被映射爲classpath:/META-INF/resources/webjars這個路徑
this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
String staticPathPattern = this.mvcProperties.getStaticPathPattern();
if (!registry.hasMappingForPattern(staticPathPattern)) {
this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(WebMvcAutoConfiguration.getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
}
}
上面代碼的第二種情況的請求路徑，String staticPathPattern = this.mvcProperties.getStaticPathPattern();實際上就是WebMvcProperties類中的this.staticPathPattern = "/**";。一切好說，問題不大。
對於上面代碼的第二種情況的映射路徑，點到對應的配置類裏面看源碼，其實就包括四個映射路徑。問題不是很大。
public class ResourceProperties {
//這個還是按照優先級順序排的, SpringBoot設計精妙啊！
private static final String[] CLASSPATH_RESOURCE_LOCATIONS = new String[]{"classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/"};
private String[] staticLocations;
private boolean addMappings;
private final ResourceProperties.Chain chain;
private final ResourceProperties.Cache cache;
public ResourceProperties() {
this.staticLocations = CLASSPATH_RESOURCE_LOCATIONS;
this.addMappings = true;
this.chain = new ResourceProperties.Chain();
this.cache = new ResourceProperties.Cache();
}
public String[] getStaticLocations() {
return this.staticLocations;
}
...
}
二、首頁
加下來分析一波web的首頁。以往的應用默認首頁都是web.xml裏面配置好的三個index。tomcat的conf文件夾下面的三大index。。。
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
還是之前那個自動配置的大類，找到下面的方法。
鎖定這個方法，點進去看源碼。發現另一個方法也和其相關。
private Optional<Resource> getWelcomePage() {
String[] locations = WebMvcAutoConfiguration.getResourceLocations(this.resourceProperties.getStaticLocations());
return Arrays.stream(locations).map(this::getIndexHtml).filter(this::isReadable).findFirst();
}
private Resource getIndexHtml(String location) {
return this.resourceLoader.getResource(location + "index.html");
}
this.resourceProperties.getStaticLocations()這些路徑就是之前靜態資源映射第二種情況的四種路徑。所以這也就解釋了，爲什麼我們沒有在之前說的四個路徑下面爲SpringBoot配置默認頁面(index.html)的時候，訪問會報錯了。
總結：一般把靜態的網站資源(HTML、CSS、JS)放在類路徑下的static文件夾下面。
三、模板引擎視圖解析部分
so easy，繼續跟蹤源碼。
下面看一下模板引擎Thymeleaf的視圖解析源碼，這個更簡單了。
@Configuration(
proxyBeanMethods = false
)
@EnableConfigurationProperties({ThymeleafProperties.class})
@ConditionalOnClass({TemplateMode.class, SpringTemplateEngine.class})
@AutoConfigureAfter({WebMvcAutoConfiguration.class, WebFluxAutoConfiguration.class})
public class ThymeleafAutoConfiguration {
public ThymeleafAutoConfiguration() {
}
...
}
可以看到默認Thymeleaf解析的路徑是類路徑下templates路徑下的html文件，去掉前後綴即可。
@ConfigurationProperties(
prefix = "spring.thymeleaf"
)
public class ThymeleafProperties {
private static final Charset DEFAULT_ENCODING;
public static final String DEFAULT_PREFIX = "classpath:/templates/";
public static final String DEFAULT_SUFFIX = ".html";
private boolean checkTemplate = true;
private boolean checkTemplateLocation = true;
private String prefix = "classpath:/templates/";
private String suffix = ".html";
private String mode = "HTML";
private Charset encoding;
private boolean cache;
private Integer templateResolverOrder;
private String[] viewNames;
private String[] excludedViewNames;
private boolean enableSpringElCompiler;
private boolean renderHiddenMarkersBeforeCheckboxes;
private boolean enabled;
private final ThymeleafProperties.Servlet servlet;
private final ThymeleafProperties.Reactive reactive;
public ThymeleafProperties() {
this.encoding = DEFAULT_ENCODING;
this.cache = true;
this.renderHiddenMarkersBeforeCheckboxes = false;
this.enabled = true;
this.servlet = new ThymeleafProperties.Servlet();
this.reactive = new ThymeleafProperties.Reactive();
}
...
}
還有一點很奇怪，爲什麼引入了模板引擎，首頁會是templates目錄下面的index.html？？？
四、擴展MVC部分
1、擴展視圖解析器
直接實現接口，加入到容器中，搞定，Debug前端控制器執行代碼也是可以獲取到自定義的視圖解析器的。@Bean只能用於類內部，@Component可以放在類上面。
@Component
public class MyViewResolver implements ViewResolver {
@Override
public View resolveViewName(String s, Locale locale) throws Exception {
//添加自己代碼
return null;
}
}
2、擴展通用部分
官方文檔說自動擴展的時候不能加@EnableWebMvc，只要加上@Configuraiton。
點進去分析這個註解，導入了某個類。
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
@Documented
@Import({DelegatingWebMvcConfiguration.class})
public @interface EnableWebMvc {
}
就是導入了DelegatingWebMvcConfiguration類。發現這個類是繼承於WebMvcConfigurationSupport的。
public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {
private final WebMvcConfigurerComposite configurers = new WebMvcConfigurerComposite();
public DelegatingWebMvcConfiguration() {
}
...
}
IDEA全局搜索兩下Shift鍵。
@Configuration(
proxyBeanMethods = false
)
@ConditionalOnWebApplication(
type = Type.SERVLET
)
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class})
@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})
@AutoConfigureOrder(-2147483638)
@AutoConfigureAfter({DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class})
public class WebMvcAutoConfiguration {
...
}
可以看到只有WebMvcConfigurationSupport這個類不存在的時候，默認配置纔會生效，就相當於不能加上@EnableWebMvc，否則SpringBoot默認的MVC配置全崩了。
public class DispatcherServlet extends FrameworkServlet {
public static final String MULTIPART_RESOLVER_BEAN_NAME = "multipartResolver";
public static final String LOCALE_RESOLVER_BEAN_NAME = "localeResolver";
public static final String THEME_RESOLVER_BEAN_NAME = "themeResolver";
public static final String HANDLER_MAPPING_BEAN_NAME = "handlerMapping";
public static final String HANDLER_ADAPTER_BEAN_NAME = "handlerAdapter";
public static final String HANDLER_EXCEPTION_RESOLVER_BEAN_NAME = "handlerExceptionResolver";
public static final String REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME = "viewNameTranslator";
public static final String VIEW_RESOLVER_BEAN_NAME = "viewResolver";
public static final String FLASH_MAP_MANAGER_BEAN_NAME = "flashMapManager";
public static final String WEB_APPLICATION_CONTEXT_ATTRIBUTE = DispatcherServlet.class.getName() + ".CONTEXT";
public static final String LOCALE_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".LOCALE_RESOLVER";
public static final String THEME_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_RESOLVER";
public static final String THEME_SOURCE_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_SOURCE";
public static final String INPUT_FLASH_MAP_ATTRIBUTE = DispatcherServlet.class.getName() + ".INPUT_FLASH_MAP";
public static final String OUTPUT_FLASH_MAP_ATTRIBUTE = DispatcherServlet.class.getName() + ".OUTPUT_FLASH_MAP";
public static final String FLASH_MAP_MANAGER_ATTRIBUTE = DispatcherServlet.class.getName() + ".FLASH_MAP_MANAGER";
public static final String EXCEPTION_ATTRIBUTE = DispatcherServlet.class.getName() + ".EXCEPTION";
public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";
private static final String DEFAULT_STRATEGIES_PATH = "DispatcherServlet.properties";
private static final String DEFAULT_STRATEGIES_PREFIX = "org.springframework.web.servlet";
protected static final Log pageNotFoundLogger = LogFactory.getLog("org.springframework.web.servlet.PageNotFound");
private static final Properties defaultStrategies;
private boolean detectAllHandlerMappings = true;
private boolean detectAllHandlerAdapters = true;
private boolean detectAllHandlerExceptionResolvers = true;
private boolean detectAllViewResolvers = true;
private boolean throwExceptionIfNoHandlerFound = false;
private boolean cleanupAfterInclude = true;
@Nullable
private MultipartResolver multipartResolver;
@Nullable
private LocaleResolver localeResolver;
@Nullable
private ThemeResolver themeResolver;
@Nullable
private List<HandlerMapping> handlerMappings;
@Nullable
private List<HandlerAdapter> handlerAdapters;
@Nullable
private List<HandlerExceptionResolver> handlerExceptionResolvers;
@Nullable
private RequestToViewNameTranslator viewNameTranslator;
@Nullable
private FlashMapManager flashMapManager;
@Nullable
private List<ViewResolver> viewResolvers;
...
}
問題不大，跟着DispatcherServlet配就可以了。
3、demo
簡單demo：
@Configuration
//@EnableWebMvc
public class MyMVCConfig implements WebMvcConfigurer {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/index").setViewName("index");
registry.addViewController("/index.html").setViewName("index");
}
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new MyInterceptor())
.addPathPatterns("/**")
.excludePathPatterns("/index", "/", "index.html")
.excludePathPatterns("/asserts/js/**", "/asserts/css/**", "/asserts/img/**")
// .excludePathPatterns("/i18n/**")
.excludePathPatterns("/login");
}
@Bean
public MyLocaleResolver localeResolver() {
return new MyLocaleResolver();
}
}
五、Boot的CRUD模板
踩了坑，國際化出現亂碼。。。
昨晚試了，根本沒用啊，TM今早可以了。。。RGL。
鏈接：https://pan.baidu.com/s/1ONiJMDvSPrIYeMA4Labi9Q
提取碼：38bb
以後SpringBoot的CRUD簡單的系統都問題不大了，該補補java基礎去了。