1. Hello World - WebService based on Spring

Create a new Maven quickstart app project in Eclipse

1. 参考此篇文章创建Maven项目(b). Web，在Eclipse创建一个基于Maven的quick start项目。其中archetype和Arfifact Id设置如下。
   
   

2. 修改pom.xml文件，增加spring依赖。

   pom.xml

   <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.xuan.flight.tutorial</groupId>
     <artifactId>hello-world-springws</artifactId>
     <version>1.0.0</version>
     <packaging>jar</packaging>
     <name>hello-world-springws</name>
     <url>http://maven.apache.org</url>
     <parent>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-parent</artifactId>
           <version>1.4.1.RELEASE</version>
       </parent>
       <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-web</artifactId>
           </dependency>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-test</artifactId>
               <scope>test</scope>
           </dependency>
           <dependency>
               <groupId>com.jayway.jsonpath</groupId>
               <artifactId>json-path</artifactId>
               <scope>test</scope>
           </dependency>
       </dependencies>
       <properties>
           <java.version>1.7</java.version>
           <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
       </properties>
    
       <build>
           <plugins>
               <plugin>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-maven-plugin</artifactId>
               </plugin>
           </plugins>
       </build>
       <repositories>
           <repository>
               <id>spring-releases</id>
               <url>https://repo.spring.io/libs-release</url>
           </repository>
       </repositories>
       <pluginRepositories>
           <pluginRepository>
               <id>spring-releases</id>
               <url>https://repo.spring.io/libs-release</url>
           </pluginRepository>
       </pluginRepositories>
   </project>

    

   
   
   

Implement Spring Web Service

1. 在包com.xuan.flight.tutorial.springws下，增加Greeting实体类。

   Greeting.java

   package com.xuan.flight.tutorial.springws;
    
   public class Greeting
   {
       private final long id;
       private final String content;
       public Greeting(long id, String content)
       {
           this.id = id;
           this.content = content;
       }
       public long getId()
       {
           return id;
       }
       public String getContent()
       {
           return content;
       }
   }

    

    

2. 在包com.xuan.flight.tutorial.springws下，增加GreetingController.java文件。实现请求处理器，在Spring中由@RestController 标记实现。

    

    

   package com.xuan.flight.tutorial.springws;
    
   import java.util.concurrent.atomic.AtomicLong;
   import org.springframework.web.bind.annotation.RequestMapping;
   import org.springframework.web.bind.annotation.RequestParam;
   import org.springframework.web.bind.annotation.RestController;
    
   @RestController
   public class GreetingController
   {
       private static final String template = "Hello, %s!";
       private final AtomicLong counter = new AtomicLong();
    
       @RequestMapping("/greeting")
       public Greeting greeting(@RequestParam(value = "name", defaultValue = "World") String name)
       {
           return new Greeting(counter.incrementAndGet(), String.format(template, name));
       }
   }

    

3. 在包com.xuan.flight.tutorial.springws下，修改已经存在的App.java文件，实现服务入口逻辑。借助于Spring的支持，我们可以将Tomcat容器嵌入到当前的程序中，让服务能够以独立的Java程序启动，无需额外部署到外部Tomcat容器中。

4. package com.xuan.flight.tutorial.springws;
    
   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
    
   @SpringBootApplication
   public class App
   {
       public static void main(String[] args)
       {
           SpringApplication.run(App.class, args);
       }
   }

    

Compile & Run

1. Eclipse默认已经自动编译完成，直接按照普通的Java程序运行即可。右键App.java -> Run As -> Java Application开始运行。
   在控制台可以看到如下的日志输出：Tomcat在8080端口作为嵌入式容器启动；当看到Started App in xxx seconds时，表明服务启动成功。
   

2. 在浏览器输入http://localhost:8080/greeting或者http://localhost:8080/greeting?name=User可以看到类似下面的输出，表明服务运行正常。

   {"id":1,"content":"Hello, World!"}

Read More

1. Building a RESTful Web Service - https://spring.io/guides/gs/rest-service/