使用Spring Boot开发Restful程序
出处：http://www.jianshu.com/p/e40b329f5544
一、简介
Spring Boot是由Pivotal团队提供的全新框架，其设计目的是用来简化新Spring应用的初始搭建以及开发过程。该框架使用了特定的方式来进行配置，从而使开发人员不再需要定义样板化的配置。通过这种方式，Boot致力于在蓬勃发展的快速应用开发领域（rapid application development）成为领导者。
多年以来，Spring IO平台饱受非议的一点就是大量的XML配置以及复杂的依赖管理。在去年的SpringOne 2GX会议上，Pivotal的CTO Adrian Colyer回应了这些批评，并且特别提到该平台将来的目标之一就是实现免XML配置的开发体验。Boot所实现的功能超出了这个任务的描述，开发人员不仅不再需要编写XML，而且在一些场景中甚至不需要编写繁琐的import语句。在对外公开的beta版本刚刚发布之时，Boot描述了如何使用该框架在140个字符内实现可运行的web应用，从而获得了极大的关注度，该样例发表在tweet上。
Spring Boot不生成代码，且完全不需要XML配置。其主要目标如下：
- 为所有的Spring开发工作提供一个更快、更广泛的入门经验。
- 开箱即用，你也可以通过修改默认值来快速满足你的项目的需求。
- 提供了一系列大型项目中常见的非功能性特性，如嵌入式服务器、安全、指标，健康检测、外部配置等。
Spring Boot官网: http://projects.spring.io/spring-boot/
二、开发环境准备
- IDE：IntelliJ IDEA
官网地址：https://www.jetbrains.com/idea/download/ - JDK：1.8
- Maven
- 数据库：MySQL
我将以一个用户积分系统为例，开发一个Restful风格的服务端
三、第一个Restful程序
1.新建一个普通Maven工程
Step1
Step2
Step3
Step4
创建项目完成后目录结构如下图所示
Step5
2.在POM文件中加入对Spring-Boot的依赖
<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>4.0.0modelVersion>
<groupId>com.bluecoffeegroupId>
<artifactId>mappartifactId>
<version>1.0-SNAPSHOTversion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>1.4.1.RELEASEversion>
<relativePath />
parent>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<java.version>1.8java.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>3.新建一个RestController来接收客户端的请求，我们来模拟一个登录请求
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;
}}- 关键字@RestController代表这个类是用Restful风格来访问的，如果是普通的WEB页面访问跳转时，我们通常会使用@Controller
- value = "/users/{username}" 代表访问的URL是"http://host:PORT/users/实际的用户名"
- method = RequestMethod.GET 代表这个HTTP请求必须是以GET方式访问
- consumes="application/json" 代表数据传输格式是json
- @PathVariable将某个动态参数放到URL请求路径中
- @RequestParam指定了请求参数名称
4.新建启动Restful服务端的启动类
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.执行MappRunApplication的Main方法启动Restful服务，可以看到控制台有如下输出
. ____ _ __ _ _
/\\\\ / ___'_ __ _ _(_)_ __ __ _ \\ \\ \\ \\
( ( )\\___ | '_ | '_| | '_ \\/ _` | \\ \\ \\ \\
\\\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: 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> 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)我们可以看到服务器是Tomcat，端口为8080
6.验证
推荐大家使用Google的Postman插件来模拟请求
模拟请求
在发起请求前，请注意需要在Headers中设置Content-Type为application/json
到此一个基本的Restful风格的服务端就已经完成了，全部编码时间不会超过5分钟！