Spring

Spring helps development teams everywhere build simple, portable, fast and flexible JVM-based systems and applications.

REST service

spring.io/guides/gs/rest-service/

Structure

.
|-- pom.xml
|-- src
|   `-- main
|       `-- java
|           `-- hello
|               |-- Application.java
|               |-- Greeting.java
|               `-- GreetingController.java
`-- target
    |-- classes
    |   `-- hello
    |       |-- Application.class
    |       |-- Greeting.class
    |       `-- GreetingController.class
    |-- generated-sources
    |   `-- annotations
    |-- gs-rest-service-0.1.0.jar
    |-- gs-rest-service-0.1.0.jar.original
    `-- maven-archiver
        `-- pom.properties

Steps

mkdir -p /tmp/greetingSpring
mkdir -p /tmp/greetingSpring/src/main/java/hello
mkdir -p /tmp/greetingSpring/target
cd /tmp/greetingSpring

pom.xml

<?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>org.springframework</groupId>
  <artifactId>gs-rest-service</artifactId>
  <version>0.1.0</version>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.1.5.RELEASE</version>
  </parent>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
  </dependencies>
<properties>
<start-class>hello.Application</start-class>
</properties>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-releases</id>
<url>http://repo.spring.io/libs-release</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-releases</id>
<url>http://repo.spring.io/libs-release</url>
</pluginRepository>
</pluginRepositories>
</project>

src/main/java/hello/Application.java

   1 package hello;
   2 
   3 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
   4 import org.springframework.boot.SpringApplication;
   5 import org.springframework.context.annotation.ComponentScan;
   6 
   7 @ComponentScan
   8 @EnableAutoConfiguration
   9 public class Application {
  10 
  11     public static void main(String[] args) {
  12         SpringApplication.run(Application.class, args);
  13     }
  14 }

src/main/java/hello/Greeting.java

   1 package hello;
   2 
   3 public class Greeting {
   4 
   5     private final long id;
   6     private final String content;
   7 
   8     public Greeting(long id, String content) {
   9         this.id = id;
  10         this.content = content;
  11     }
  12 
  13     public long getId() {
  14         return id;
  15     }
  16 
  17     public String getContent() {
  18         return content;
  19     }
  20 }

src/main/java/hello/GreetingController.java

   1 package hello;
   2 
   3 import java.util.concurrent.atomic.AtomicLong;
   4 import org.springframework.web.bind.annotation.RequestMapping;
   5 import org.springframework.web.bind.annotation.RequestParam;
   6 import org.springframework.web.bind.annotation.RestController;
   7 
   8 @RestController
   9 public class GreetingController {
  10 
  11     private static final String template = "Hello, %s!";
  12     private final AtomicLong counter = new AtomicLong();
  13 
  14     @RequestMapping("/greeting")
  15     public Greeting greeting(@RequestParam(value="name", required=false, defaultValue="World") String name) {
  16         return new Greeting(counter.incrementAndGet(),
  17                             String.format(template, name));
  18     }
  19 }

Build with

mvn clean compile package

Run with:

jar -tf target/gs-rest-service-0.1.0.jar # check JAR contents
java -jar target/gs-rest-service-0.1.0.jar
open URL http://localhost:8080/greeting

Tomcat REST service

Structure

.
|-- pom.xml
|-- src
    `-- main
        `-- java
            `-- hello
                |-- Application.java
                |-- Greeting.java
                `-- GreetingController.java

pom.xml

   1 <project xmlns="http://maven.apache.org/POM/4.0.0" 
   2 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   3 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
   4 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   5     <modelVersion>4.0.0</modelVersion>
   6     <groupId>org.springframework</groupId>
   7     <artifactId>gs-rest-service-tomcat</artifactId>
   8     <version>0.1.0</version>
   9     <packaging>war</packaging>
  10 
  11     <parent>
  12         <groupId>org.springframework.boot</groupId>
  13         <artifactId>spring-boot-starter-parent</artifactId>
  14         <version>1.1.5.RELEASE</version>
  15     </parent>
  16 
  17     <dependencies>
  18         <dependency>
  19             <groupId>org.springframework.boot</groupId>
  20             <artifactId>spring-boot-starter-web</artifactId>
  21             <scope>compile</scope> 
  22         </dependency>
  23     </dependencies>
  24 
  25     <properties>
  26         <start-class>hello.Application</start-class>
  27     </properties>
  28     <build>
  29         <plugins>
  30             <plugin>
  31                 <artifactId>maven-compiler-plugin</artifactId>
  32                 <version>2.3.2</version>
  33             </plugin>
  34         </plugins>
  35     </build>
  36     <repositories>
  37         <repository>
  38             <id>spring-releases</id>
  39             <url>http://repo.spring.io/libs-release</url>
  40         </repository>
  41     </repositories>
  42     <pluginRepositories>
  43         <pluginRepository>
  44             <id>spring-releases</id>
  45             <url>http://repo.spring.io/libs-release</url>
  46         </pluginRepository>
  47     </pluginRepositories>
  48 </project>

src/main/java/hello/Application.java

   1 package hello;
   2 
   3 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
   4 import org.springframework.boot.SpringApplication;
   5 import org.springframework.context.annotation.ComponentScan;
   6 import org.springframework.boot.context.web.SpringBootServletInitializer;
   7 import org.springframework.boot.builder.SpringApplicationBuilder;
   8 import org.springframework.context.annotation.Configuration;
   9 
  10 @ComponentScan
  11 @EnableAutoConfiguration
  12 @Configuration
  13 public class Application  extends SpringBootServletInitializer  {
  14 
  15     public static void main(String[] args) {
  16         SpringApplication.run(appClass, args);
  17     }
  18 
  19     @Override
  20     protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
  21         return application.sources(appClass);
  22     }
  23 
  24     private static Class<Application> appClass = Application.class;
  25 }

src/main/java/hello/Greeting.java

   1 package hello;
   2 
   3 public class Greeting {
   4 
   5     private final long id;
   6     private final String content;
   7 
   8     public Greeting(long id, String content) {
   9         this.id = id;
  10         this.content = content;
  11     }
  12 
  13     public long getId() {
  14         return id;
  15     }
  16 
  17     public String getContent() {
  18         return content;
  19     }
  20 }

src/main/java/hello/GreetingController.java

   1 package hello;
   2 
   3 import java.util.concurrent.atomic.AtomicLong;
   4 import org.springframework.web.bind.annotation.RequestMapping;
   5 import org.springframework.web.bind.annotation.RequestParam;
   6 import org.springframework.web.bind.annotation.RestController;
   7 
   8 @RestController
   9 public class GreetingController {
  10 
  11     private static final String template = "Hello Tomcat, %s!";
  12     private final AtomicLong counter = new AtomicLong();
  13 
  14     @RequestMapping("/greetingTomcat")
  15     public Greeting greeting(@RequestParam(value="name", required=false, defaultValue="World") String name) {
  16         return new Greeting(counter.incrementAndGet(), String.format(template, name));
  17     }
  18 }

Build and deploy

mvn clean compile package install
cp target/gs-rest-service-tomcat-0.1.0.war /usr/local/tomcat/webapps/
cp target/gs-rest-service-tomcat-0.1.0.war /opt/apache-tomcat-7.0.53/webapps/ # in alternative
Open http://localhost:8080/gs-rest-service-tomcat-0.1.0/greetingTomcat

Spring MVC

Structure:

.
|-- pom.xml
|-- src
    `-- main
        |-- java
        |   `-- hello
        |       |-- Application.java
        |       `-- GreetingController.java
        `-- resources
            `-- templates
                `-- greeting.html

mkdir -p src/main/java/hello
mkdir -p src/main/resources/templates/
nano pom.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   3     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   4     <modelVersion>4.0.0</modelVersion>
   5     <groupId>org.springframework</groupId>
   6     <artifactId>gs-serving-web-content</artifactId>
   7     <version>0.1.0</version>
   8     <parent>
   9         <groupId>org.springframework.boot</groupId>
  10         <artifactId>spring-boot-starter-parent</artifactId>
  11         <version>1.1.8.RELEASE</version>
  12     </parent>
  13     <dependencies>
  14         <dependency>
  15             <groupId>org.springframework.boot</groupId>
  16             <artifactId>spring-boot-starter-thymeleaf</artifactId>
  17         </dependency>
  18     </dependencies>
  19     <properties>
  20         <start-class>hello.Application</start-class>
  21     </properties>
  22     <build>
  23         <plugins>
  24             <plugin>
  25                 <groupId>org.springframework.boot</groupId>
  26                 <artifactId>spring-boot-maven-plugin</artifactId>
  27             </plugin>
  28         </plugins>
  29     </build>
  30     <repositories>
  31         <repository>
  32             <id>spring-milestone</id>
  33             <url>http://repo.spring.io/libs-release</url>
  34         </repository>
  35     </repositories>
  36     <pluginRepositories>
  37         <pluginRepository>
  38             <id>spring-milestone</id>
  39             <url>http://repo.spring.io/libs-release</url>
  40         </pluginRepository>
  41     </pluginRepositories>
  42 </project>

cd src/main/java/hello/
nano GreetingController.java

   1 package hello;
   2 
   3 import org.springframework.stereotype.Controller;
   4 import org.springframework.ui.Model;
   5 import org.springframework.web.bind.annotation.RequestMapping;
   6 import org.springframework.web.bind.annotation.RequestParam;
   7 
   8 @Controller
   9 public class GreetingController {
  10 
  11     @RequestMapping("/greeting")
  12     public String greeting(@RequestParam(value="name", required=false, defaultValue="World") String name, Model model) {
  13         model.addAttribute("name", name);
  14         return "greeting";
  15     }
  16 
  17 }

nano src/main/resources/templates/greeting.html

   1 <!DOCTYPE HTML>
   2 <html xmlns:th="http://www.thymeleaf.org">
   3 <head>
   4     <title>Getting Started: Serving Web Content</title>
   5     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
   6 </head>
   7 <body>
   8     <p th:text="'Hello, ' + ${name} + '!'" />
   9 </body>
  10 </html>

nano src/main/java/hello/Application.java

   1 package hello;
   2 
   3 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
   4 import org.springframework.boot.SpringApplication;
   5 import org.springframework.context.annotation.ComponentScan;
   6 
   7 @ComponentScan
   8 @EnableAutoConfiguration
   9 public class Application {
  10 
  11     public static void main(String[] args) {
  12         SpringApplication.run(Application.class, args);
  13     }
  14 
  15 }

mvn clean compile package install
java -jar target/gs-serving-web-content-0.1.0.jar
Open http://localhost:8080/greeting?name=Yooo