Spring @GetMapping
last modified October 18, 2023
In this article we show how to use @GetMapping annotation to map HTTP GET requests onto specific handler methods.
Spring is a popular Java application framework for creating enterprise applications.
@GetMapping
@GetMapping annotation maps HTTP GET requests onto specific handler
methods. It is a composed annotation that acts as a shortcut for
@RequestMapping(method = RequestMethod.GET).
Spring @GetMapping example
The following application uses @GetMapping to map two request
paths onto handler methods. In this example, we use annotations to
set up a Spring web application.
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
This is the project structure.
<?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>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
<spring-version>5.3.23</spring-version>
</properties>
<dependencies>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.4.0</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>3.3.2</version>
</plugin>
<plugin>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>9.4.49.v20220914</version>
</plugin>
</plugins>
</build>
</project>
In the pom.xml file we have the following dependencies:
logback-classic, javax.servlet-api,
junit, spring-webmvc, and spring-test.
<?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>
The logback.xml is a configuration file for the Logback logging
library.
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 registers the Spring
DispatcherServlet, which is a front controller for a Spring web
application.
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[]{WebConfig.class};
}
The getServletConfigClasses returns a web configuration class.
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 {
}
The WebConfig enables Spring MVC annotations with
@EnableWebMvc and configures component scanning for the
com.zetcode package.
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 provides mappings between request paths and handler
methods.
@RestController
public class MyController {
@RestController is used for creating restful controllers, which do
not use a view technology. The methods typically return XML, JSON, or plain
text.
@GetMapping(value="/", produces = MediaType.TEXT_PLAIN_VALUE)
public String index() {
return "This is Home page";
}
The @GetMapping maps a / root path from a GET request
to the index method. It returns a plain text.
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 tests the two pages.
$ curl localhost:8080 This is Home page $ curl localhost:8080/hello Hello there!
We run the application and create two GET requests with curl tool.
In this article we have presented the @GetMapping annotation.
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