Spring 自定义 404 错误页面教程 · ZetCode 中文系列教程

# Spring 自定义 404 错误页面教程 > 原文： [http://zetcode.com/spring/custom404page/](http://zetcode.com/spring/custom404page/) Spring 自定义 404 错误页面教程展示了如何在 Spring Web 应用中创建自定义 404 错误页面。 Spring 是用于创建企业应用的流行 Java 应用框架。 ## 404 代码 HTTP 404 或 404 未找到是计算机网络通信中的超文本传输协议（HTTP）标准响应代码，用于指示客户端能够与给定服务器进行通信，但是服务器找不到所请求的资源。 ## Spring 自定义 404 错误页面示例以下应用使用创建自定义 404 错误页面。默认情况下，当找不到资源时，将显示 Tomcat 的 404 错误页面。 ```java src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ └───controller │ │ ControllerAdvisor.java │ │ MyController.java │ └───resources │ │ logback.xml │ └───templates │ │ index.html │ └───error │ 404.html └───test └───java ``` 这是项目结构。 `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>custom404page</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，我们具有以下依存关系：`logback-classic`，`javax.servlet-api`，`spring-webmvc`和`thymeleaf-spring5`以及`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> ``` 这是`logback.xml`配置文件。 `com/zetcode/config/MyWebInitializer.java` ```java package com.zetcode.config; import org.springframework.context.annotation.Configuration; import org.springframework.web.context.WebApplicationContext; import org.springframework.web.servlet.DispatcherServlet; import org.springframework.web.servlet.FrameworkServlet; 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[]{"/"}; } @Override protected FrameworkServlet createDispatcherServlet(WebApplicationContext servletAppContext) { var dispatcher = (DispatcherServlet) super.createDispatcherServlet(servletAppContext); dispatcher.setThrowExceptionIfNoHandlerFound(true); return dispatcher; } } ``` `MyWebInitializer`初始化 Spring Web 应用。它包含一个配置类：`WebConfig`。 ```java @Override protected FrameworkServlet createDispatcherServlet(WebApplicationContext servletAppContext) { var dispatcher = (DispatcherServlet) super.createDispatcherServlet(servletAppContext); dispatcher.setThrowExceptionIfNoHandlerFound(true); return dispatcher; } ``` 使用`setThrowExceptionIfNoHandlerFound()`，我们将 Spring 配置为在找不到资源时抛出`NoHandlerFoundException`。如果我们在此行中添加注释，则会显示 Web 服务器的 404 错误页面。 `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.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("classpath:/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; } } ``` `WebConfig`配置 Thymeleaf 模板引擎。 Thymeleaf 模板文件位于类路径的`templates`子目录中。 `com/zetcode/controller/MyController.java` ```java package com.zetcode.controller; import org.springframework.http.MediaType; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.GetMapping; import java.time.LocalDateTime; @Controller public class MyController { @GetMapping(value = "/", produces = MediaType.TEXT_HTML_VALUE) public String home(Model model) { model.addAttribute("now", LocalDateTime.now()); return "index"; } } ``` `MyController`包含主页的一种路由。 `com/zetcode/controller/ControllerAdvisor.java` ```java package com.zetcode.controller; import org.springframework.web.bind.annotation.ControllerAdvice; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.NoHandlerFoundException; @ControllerAdvice public class ControllerAdvisor { @ExceptionHandler(NoHandlerFoundException.class) public ModelAndView handle(Exception ex) { var mv = new ModelAndView(); mv.addObject("message", ex.getMessage()); mv.setViewName("error/404"); return mv; } } ``` `ControllerAdvisor`包含`NoHandlerFoundException`的处理器。它显示`404.html`错误页面，位于`resources/templates/error/404.html`中。 `resources/templates/error/404.html` ```java <!doctype html> <html xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Resource not found</title> </head> <body> <h2>404 - resource not found</h2> </body> </html> ``` `404.html`是我们的自定义 404 错误页面。 `resources/templates/index.html` ```java <!DOCTYPE html> <html xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Home page</title> </head> <body> This is home page. Today is </body> </html> ``` 这是主页。在本教程中，我们在 Spring 应用中创建了一个自定义 404 错误页面。您可能也对这些相关教程感兴趣： [Spring WebJars 教程](/spring/webjars/)， [Spring `@GetMapping`教程](/spring/getmapping/)， [Spring `DefaultServlet`教程](/spring/defaultservlet/)， [Spring Web 应用简介](/articles/springwebfirst/)和 [Java 教程](/lang/java/)。