Spring ResourceHandlerRegistry教程 · ZetCode 中文系列教程

# Spring `ResourceHandlerRegistry`教程 > 原文： [http://zetcode.com/spring/resourcehandlerregistry/](http://zetcode.com/spring/resourcehandlerregistry/) Spring `ResourceHandlerRegistry`教程展示了如何在 Spring Web 應用中提供靜態資產，例如圖像，CSS 或 JavaScript 文件。 Spring 是用于創建企業應用的流行 Java 應用框架。 ## `ResourceHandlerRegistry` `ResourceHandlerRegistry`存儲用于通過 Spring MVC 服務靜態資源（例如圖像，css 文件等）的資源處理器的注冊。它允許設置為在 Web 瀏覽器中高效加載而優化的緩存頭。可以在 Web 應用根目錄下，類路徑等位置之外的位置提供資源。 ## Spring `ResourceHandlerRegistry`示例以下應用使用`ResourceHandlerRegistry`在 Spring Web 應用中注冊靜態資產。我們使用`addResourceHandlers()`為 CSS 和 JavaScript 文件注冊處理器和位置。我們將 Thymeleaf 用作視圖引擎。我們使用 Thymeleaf 的`@{}`語法指向靜態資源。 ```java pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ └───controller │ │ MyController.java │ ├───resources │ │ │ logback.xml │ │ └───static │ │ ├───css │ │ │ format.css │ │ └───js │ │ main.js │ └───webapp │ └───WEB-INF │ └───templates │ homePage.html └───test └───java ``` 這是項目結構。 `pom.xml` ```java <?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.zetcode</groupId> <artifactId>staticresources</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>11</maven.compiler.source> <maven.compiler.target>11</maven.compiler.target> </properties> <dependencies> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.3</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.1.3.RELEASE</version> </dependency> <dependency> <groupId>org.thymeleaf</groupId> <artifactId>thymeleaf-spring5</artifactId> <version>3.0.11.RELEASE</version> </dependency> <dependency> <groupId>org.thymeleaf</groupId> <artifactId>thymeleaf</artifactId> <version>3.0.11.RELEASE</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>3.2.2</version> </plugin> </plugins> </build> </project> ``` 在`pom.xml`文件中，我們具有以下依存關系：`logback-classic`，`javax.servlet-api`，`spring-webmvc`，`thymeleaf-spring5`和`thymeleaf`。 `resources/logback.xml` ```java <?xml version="1.0" encoding="UTF-8"?> <configuration> <logger name="org.springframework" level="ERROR"/> <logger name="com.zetcode" level="INFO"/> <appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender"> <encoder> <Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n </Pattern> </encoder> </appender> <root> <level value="INFO" /> <appender-ref ref="consoleAppender" /> </root> </configuration> ``` `logback.xml`是 Logback 日志庫的配置文件。 `resources/css/format.css` ```java p { background-color: aquamarine; } ``` 這是`format.css`文件。它格式化`p`元素。 `resources/js/main.js` ```java const el = document.getElementById("block"); el.style.border = '1px dashed gray'; ``` 這是`main.js`文件。它將邊框添加到`div`元素。請注意，即使 JavaScript 在科學方面提供了動態功能，但從 Spring 的角度來看，它仍被視為靜態資源。 `com/zetcode/config/MyWebInitializer.java` ```java package com.zetcode.config; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer; @Configuration public class MyWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer { @Override protected Class<?>[] getRootConfigClasses() { return null; } @Override protected Class<?>[] getServletConfigClasses() { return new Class[]{WebConfig.class}; } @Override protected String[] getServletMappings() { return new String[]{"/*"}; } } ``` `MyWebInitializer`注冊 Spring `DispatcherServlet`，它是 Spring Web 應用的前端控制器。 ```java @Override protected Class<?>[] getServletConfigClasses() { return new Class[]{WebConfig.class}; } ``` `getServletConfigClasses()`返回 Web 配置類。 `com/zetcode/config/WebConfig.java` ```java package com.zetcode.config; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.ViewResolver; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry; import org.springframework.web.servlet.config.annotation.ViewResolverRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; import org.thymeleaf.spring5.SpringTemplateEngine; import org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver; import org.thymeleaf.spring5.view.ThymeleafViewResolver; @Configuration @EnableWebMvc @ComponentScan(basePackages = {"com.zetcode"}) public class WebConfig implements WebMvcConfigurer { @Autowired private ApplicationContext applicationContext; @Bean public SpringResourceTemplateResolver templateResolver() { var templateResolver = new SpringResourceTemplateResolver(); templateResolver.setApplicationContext(applicationContext); templateResolver.setPrefix("/WEB-INF/templates/"); templateResolver.setSuffix(".html"); return templateResolver; } @Bean public SpringTemplateEngine templateEngine() { var templateEngine = new SpringTemplateEngine(); templateEngine.setTemplateResolver(templateResolver()); templateEngine.setEnableSpringELCompiler(true); return templateEngine; } @Bean public ViewResolver viewResolver() { var resolver = new ThymeleafViewResolver(); var registry = new ViewResolverRegistry(null, applicationContext); resolver.setTemplateEngine(templateEngine()); registry.viewResolver(resolver); return resolver; } @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("/js/**").addResourceLocations("classpath:/static/js/"); registry.addResourceHandler("/css/**").addResourceLocations("classpath:/static/css/"); } } ``` `WebConfig`通過`@EnableWebMvc`啟用 Spring MVC 注解，并為`com.zetcode`包配置組件掃描。它設置 Thymeleaf 引擎并注冊靜態資源處理器。 ```java @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("/js/**").addResourceLocations("classpath:/static/js/"); registry.addResourceHandler("/css/**").addResourceLocations("classpath:/static/css/"); } ``` 我們重寫`addResourceHandlers()`來注冊 JavaScript 和 CSS 文件的處理器和位置。 `com/zetcode/controller/MyController.java` ```java package com.zetcode.controller; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; @Controller public class MyController { @GetMapping(value="/") public String homePage() { return "homePage"; } } ``` `MyController`提供主頁的映射。在應用中，我們僅使用一個視圖。 `WEB-INF/templates/homePage.html` ```java <!DOCTYPE html> <html xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Home page</title> <link rel="stylesheet" th:href="@{/css/format.css}"> </head> <body> <div id="block"> <p> This is home page. </p> </div> <script th:src="@{/js/main.js}"></script> </body> </html> ``` `homePage.html`是主頁的視圖。它使用靜態資源；一個 CSS 和一個 JavaScript 文件。 ```java <link rel="stylesheet" th:href="@{/css/format.css}"> ``` 我們使用特定的 Thymeleaf 語法引用靜態文件。在本教程中，我們展示了如何向 Spring 的`ResourceHandlerRegistry`注冊靜態資源。您可能也對這些相關教程感興趣： [Spring `BeanDefinitionBuilder`教程](/spring/beandefinitionbuilder/)， [Spring 資源教程](/spring/resource/)， [Spring `@GetMapping`教程](/spring/getmapping/)和 [Java 教程](/lang/java/)。