Spring @GetMapping教程 · ZetCode 中文系列教程

# Spring `@GetMapping`教程 > 原文： [http://zetcode.com/spring/getmapping/](http://zetcode.com/spring/getmapping/) Spring `@GetMapping`教程展示了如何使用`@GetMapping`注解将 HTTP GET 请求映射到特定的处理器方法。 Spring 是用于创建企业应用的流行 Java 应用框架。 ## `@GetMapping` `@GetMapping`注解将 HTTP GET 请求映射到特定的处理器方法。它是一个组合的注解，用作`@RequestMapping(method = RequestMethod.GET)`的快捷方式。 ## Spring `@GetMapping`示例以下应用使用`@GetMapping`将两个请求路径映射到处理器方法。在此示例中，我们使用注解来设置 Spring Web 应用。 ```java pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ └───controller │ │ MyController.java │ └───resources │ logback.xml └───test └───java └───com └───zetcode └───controller MyControllerTest.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>getmapping</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>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring-version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring-version}</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`文件中，我们具有以下依存关系：`logback-classic`，`javax.servlet-api`，`junit`，`spring-webmvc`和`spring-test`。 `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.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.EnableWebMvc; @Configuration @EnableWebMvc @ComponentScan(basePackages = {"com.zetcode"}) public class WebConfig { } ``` `WebConfig`通过`@EnableWebMvc`启用 Spring MVC 注解，并为`com.zetcode`包配置组件扫描。 `com/zetcode/controller/MyController.java` ```java package com.zetcode.controller; import org.springframework.http.MediaType; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class MyController { @GetMapping(value="/", produces = MediaType.TEXT_PLAIN_VALUE) public String index() { return "This is Home page"; } @GetMapping(value="/hello", produces = MediaType.TEXT_PLAIN_VALUE) public String sayHello() { return "Hello there!"; } } ``` `MyController`提供请求路径和处理器方法之间的映射。 ```java @RestController public class MyController { ``` `@RestController`用于创建不使用视图技术的静态控制器。这些方法通常返回 XML，JSON 或纯文本。 ```java @GetMapping(value="/", produces = MediaType.TEXT_PLAIN_VALUE) public String index() { return "This is Home page"; } ``` `@GetMapping`将从 GET 请求到`index()`方法的`/`根路径映射。它返回纯文本。 `com/zetcode/controller/MyControllerTest.java` ```java package com.zetcode.controller; import org.junit.Before; import org.junit.Test; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.setup.MockMvcBuilders; import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get; import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content; import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status; public class MyControllerTest { private MockMvc mockMvc; @Before public void setup() { this.mockMvc = MockMvcBuilders.standaloneSetup(new MyController()).build(); } @Test public void testHomePage() throws Exception { this.mockMvc.perform(get("/")).andExpect(status().isOk()) .andExpect(content().string("This is Home page")); } @Test public void testHelloPage() throws Exception { this.mockMvc.perform(get("/hello")).andExpect(status().isOk()) .andExpect(content().string("Hello there!")); } } ``` `MyControllerTest`测试两个页面。 ```java $ curl localhost:8080 This is Home page $ curl localhost:8080/hello Hello there! ``` 我们运行该应用，并使用`curl`工具创建两个 GET 请求。在本教程中，我们介绍了`@GetMapping`注解。您可能也对这些相关教程感兴趣： [Spring `@PostMapping`教程](/spring/postmapping/)， [Spring 单例范围 bean](/spring/singletonscope/) ， [Spring `@ComponentScan`教程](/spring/componentscan/)， [Spring 配置文件 XML 教程](/spring/profilexml/) 或 [Java 教程](/lang/java/)或列出[所有 Spring 教程](/all/#spring)。