Spring ModelAndView教程 · ZetCode 中文系列教程

# Spring `ModelAndView`教程 > 原文： [http://zetcode.com/spring/modelandview/](http://zetcode.com/spring/modelandview/) Spring `ModelAndView`教程展示了如何在 Spring Web 应用的控制器中使用`ModelAndView`。 Spring 是用于创建企业应用的流行 Java 应用框架。 ## `ModelAndView` `ModelAndView`是 Web MVC 框架中`Model`和`View`的持有者。这两类是截然不同的。 `ModelAndView`仅保留两者，以使控制器有可能在单个返回值中返回模型和视图。该视图由`ViewResolver`对象解析；该模型是存储在`Map`中的数据。 ## Spring `ModelAndView`示例以下应用使用`ModelAndView`在 Spring 控制器中一步返回模型和视图。我们使用 Freemarker 进行视图解析。 ```java pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ └───controller │ │ MyController.java │ └───resources │ │ logback.xml │ └───templates │ index.ftl │ show.ftl └───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>springmodelandview</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> <spring-version>5.1.3.RELEASE</spring-version> </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-context-support</artifactId> <version>5.1.3.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.1.3.RELEASE</version> </dependency> <dependency> <groupId>org.freemarker</groupId> <artifactId>freemarker</artifactId> <version>2.3.28</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>3.2.2</version> </plugin> <plugin> <groupId>org.eclipse.jetty</groupId> <artifactId>jetty-maven-plugin</artifactId> <version>9.4.14.v20181114</version> </plugin> </plugins> </build> </project> ``` 在`pom.xml`中，我们具有必要的依赖项。 `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 日志库的配置文件。 `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`注册 Spring `DispatcherServlet`，它是 Spring Web 应用的前端控制器。 ```java @Override protected Class<?>[] getServletConfigClasses() { return new Class[]{WebConfig.class}; } ``` `getServletConfigClasses()`返回 Web 配置类。 `com/zetcode/config/WebConfig.java` ```java package com.zetcode.config; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer; import org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver; @Configuration @EnableWebMvc @ComponentScan(basePackages = {"com.zetcode"}) public class WebConfig implements WebMvcConfigurer { @Bean public FreeMarkerViewResolver freemarkerViewResolver() { var resolver = new FreeMarkerViewResolver(); resolver.setCache(true); resolver.setSuffix(".ftl"); return resolver; } @Bean public FreeMarkerConfigurer freemarkerConfig() { var freeMarkerConfigurer = new FreeMarkerConfigurer(); freeMarkerConfigurer.setTemplateLoaderPath("classpath:/templates/"); return freeMarkerConfigurer; } } ``` `WebConfig`配置 FreeMarker 模板引擎。我们将模板文件的位置设置为`classpath`上的`templates`目录。（`resources`在类路径上。） `com/zetcode/controller/MyController.java` ```java package com.zetcode.controller; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.servlet.ModelAndView; import java.time.LocalDateTime; import java.time.format.DateTimeFormatter; @Controller public class MyController { @GetMapping(value = "/") public String home() { return "index"; } @GetMapping(value = "/show") public ModelAndView show() { var mav = new ModelAndView(); var now = LocalDateTime.now(); var formatter = DateTimeFormatter.ISO_DATE_TIME; var dateTimeFormatted = formatter.format(now); mav.addObject("now", dateTimeFormatted); mav.setViewName("show"); return mav; } } ``` `MyController`提供了两个 GET 映射。 ```java @GetMapping(value = "/show") public ModelAndView show() { ``` `show()`方法返回`ModelAndView`。 ```java var mav = new ModelAndView(); var now = LocalDateTime.now(); var formatter = DateTimeFormatter.ISO_DATE_TIME; var dateTimeFormatted = formatter.format(now); mav.addObject("now", dateTimeFormatted); mav.setViewName("show"); return mav; ``` 创建一个`ModelAndView`并填充数据。数据是格式化的日期时间对象。视图名称由`setViewName()`设置。 Spring 将视图名称解析为`show.ftl`。 `resources/templates/index.ftl` ```java <!DOCTYPE html> <html> <head> <title>Home</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <p> <a href="show">Show today's datetime</a> </p> </body> </html> ``` 主页包含一个链接，以显示今天的日期时间。 `resources/templates/show.ftl` ```java <!DOCTYPE html> <html> <head> <title>Today's date</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <p> Today is: ${now} </p> </body> </html> ``` 在`show.ftl`视图中，我们使用`${}`语法显示当前日期时间。 ```java $ mvn jetty:run ``` 我们运行服务器并找到`localhost:8080`以获取具有链接的主页。在本教程中，我们使用`ModelAndView`来组织模型和视图。您可能也对这些相关教程感兴趣： [Spring `@Configuration`教程](/spring/configuration/)， [Spring `@GetMapping`教程](/spring/getmapping/)， [Java 教程](/lang/java/)或列出[所有 Spring 教程](/all/#spring)。