一、簡介

最近團隊中Android和IOS的童鞋向我提出來一個要求，想學(xué)習(xí)一下服務(wù)端是如何開發(fā)的。我們的后端主要是用Spring MVC來實現(xiàn)Restful風(fēng)格的接口，業(yè)務(wù)層和數(shù)據(jù)層使用Spring Framework+Mybatis來實現(xiàn)。但是這些東西一來配置文件太多，原理也很難快速掌握，對于前端童鞋來說，門檻較高，有沒有更便捷的框架供大家學(xué)習(xí)呢？經(jīng)過幾天的時間研究，終于找到了Spring Boot這個大殺器。

Spring Boot 是由Pivotal團隊提供的全新框架，其設(shè)計目的是用來簡化新Spring應(yīng)用的初始搭建以及開發(fā)過程。該框架使用了特定的方式來進行配置，從而使開發(fā)人員不再需要定義樣板化的配置。通過這種方式，Boot致力于在蓬勃發(fā)展的快速應(yīng)用開發(fā)領(lǐng)域（rapid application development）成為領(lǐng)導(dǎo)者。

Spring Boot不生成代碼，且完全不需要XML配置。其主要目標如下：

• 為所有的Spring開發(fā)工作提供一個更快、更廣泛的入門經(jīng)驗。
• 開箱即用，你也可以通過修改默認值來快速滿足你的項目的需求。
• 提供了一系列大型項目中常見的非功能性特性，如嵌入式服務(wù)器、安全、指標，健康檢測、外部配置等。

Spring Boot官網(wǎng): http://projects.spring.io/spring-boot/

二、開發(fā)環(huán)境準備

• IDE：IntelliJ IDEA
  官網(wǎng)地址：https://www.jetbrains.com/idea/download/
• JDK：1.8
• Maven
• 數(shù)據(jù)庫：MySQL

我將以一個用戶積分系統(tǒng)為例，開發(fā)一個Restful風(fēng)格的服務(wù)端

三、第一個Restful程序

1.新建一個普通Maven工程

Step1

Step2

Step3

Step4

創(chuàng)建項目完成后目錄結(jié)構(gòu)如下圖所示

Step5

2.在POM文件中加入對Spring-Boot的依賴

<?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.bluecoffee</groupId>
    <artifactId>mapp</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>


    <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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

3.新建一個RestController來接收客戶端的請求，我們來模擬一個登錄請求

package com.yepit.mapp.rest;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.bind.annotation.*;

/**
 * Created by qianlong on 16/7/20.
 */
@RestController
public class UserController {

    @RequestMapping(value = "/users/{username}",method = RequestMethod.GET,consumes="application/json")
    public String getUser(@PathVariable String username, @RequestParam String pwd){
        return "Welcome,"+username;
    }}

• 關(guān)鍵字@RestController代表這個類是用Restful風(fēng)格來訪問的，如果是普通的WEB頁面訪問跳轉(zhuǎn)時，我們通常會使用@Controller
• value = "/users/{username}" 代表訪問的URL是"http://host:PORT/users/實際的用戶名"
• method = RequestMethod.GET 代表這個HTTP請求必須是以GET方式訪問
• consumes="application/json" 代表數(shù)據(jù)傳輸格式是json
• @PathVariable將某個動態(tài)參數(shù)放到URL請求路徑中
• @RequestParam指定了請求參數(shù)名稱

4.新建啟動Restful服務(wù)端的啟動類

package com.yepit.mapp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * Created by qianlong on 16/7/20.
 */
@SpringBootApplication
public class MappRunApplication {

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

5.執(zhí)行MappRunApplication的Main方法啟動Restful服務(wù)，可以看到控制臺有如下輸出

  .   ____          _            __ _ _
 /\\\\ / ___'_ __ _ _(_)_ __  __ _ \\ \\ \\ \\
( ( )\\___ | '_ | '_| | '_ \\/ _` | \\ \\ \\ \\
 \\\\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.3.3.RELEASE)

2016-07-20 16:49:43.334  INFO 2106 --- [           main] com.yepit.mapp.MappRunApplication        : Starting MappRunApplication on bogon with PID 2106 (/Users/qianlong/workspace/spring-boot-samples/target/classes started by qianlong in /Users/qianlong/workspace/spring-boot-samples)
2016-07-20 16:49:43.338  INFO 2106 --- [           main] com.yepit.mapp.MappRunApplication        : No active profile set, falling back to default profiles: default
2016-07-20 16:49:43.557  INFO 2106 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@543e710e: startup date [Wed Jul 20 16:49:43 CST 2016]; root of context hierarchy
2016-07-20 16:49:44.127  INFO 2106 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]
2016-07-20 16:49:44.658  INFO 2106 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2016-07-20 16:49:44.672  INFO 2106 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-07-20 16:49:44.673  INFO 2106 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.32
2016-07-20 16:49:44.759  INFO 2106 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-07-20 16:49:44.759  INFO 2106 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1207 ms
2016-07-20 16:49:44.972  INFO 2106 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2016-07-20 16:49:44.977  INFO 2106 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-07-20 16:49:44.978  INFO 2106 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-07-20 16:49:44.978  INFO 2106 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-07-20 16:49:44.978  INFO 2106 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2016-07-20 16:49:45.184  INFO 2106 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@543e710e: startup date [Wed Jul 20 16:49:43 CST 2016]; root of context hierarchy
2016-07-20 16:49:45.251  INFO 2106 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/users],methods=[GET],consumes=[application/json]}" onto public java.lang.String com.yepit.mapp.rest.UserController.getUser(java.lang.String,java.lang.String)
2016-07-20 16:49:45.253  INFO 2106 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2016-07-20 16:49:45.254  INFO 2106 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2016-07-20 16:49:45.275  INFO 2106 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-07-20 16:49:45.275  INFO 2106 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-07-20 16:49:45.306  INFO 2106 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-07-20 16:49:45.380  INFO 2106 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-07-20 16:49:45.462  INFO 2106 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2016-07-20 16:49:45.467  INFO 2106 --- [           main] com.yepit.mapp.MappRunApplication        : Started MappRunApplication in 2.573 seconds (JVM running for 3.187)

我們可以看到服務(wù)器是Tomcat，端口為8080

6.驗證
推薦大家使用Google的Postman插件來模擬請求

模擬請求

到此一個基本的Restful風(fēng)格的服務(wù)端就已經(jīng)完成了，全部編碼時間不會超過5分鐘！

完整代碼戳這里: Chapter 1 - 5分鐘構(gòu)建一個基本的Restful程序