最近要开发Restful风格的WebService,但是不是很了解Rest-Api的开发流程，于是spring官网看了搭建rest－api的例子,从pom.xml开始，简单记录下一个Rest－api的开发。

一.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>1.5.8.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>1.8</java.version>
    </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>

二.Bean

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;
    }
}

三.Controller的创建

为了实现Restful web Service，Http请求由控制器处理，这些组件通过@RestController识别。

@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));
    }
}

四.启动方法

@SpringBootApplication

public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Springboot展现了简单的方法创建了独立应用程序。将所有的内容打包在一个单一的、可执行的JAR文件中，由一个Java main()方法驱动

五.打包成可运行的jar

Gradle 构建
java -jar build/libs/gs-rest-service-0.1.0.jar
Maven构建
java -jar target/gs-rest-service-0.1.0.jar

六.测试

输入http://localhost:8080/greeting
{"id":1,"content":"Hello, World!"}
输入http://localhost:8080/greeting?name=user
{"id":2,"content":"Hello, User!"}

还要注意id属性从1到2的变化。这证明在处理多个请求的相同的GreetingController实例，并且它的计数器字段在每次调用时都按预期递增。