使用Spring Boot开发Restful程序

Myth丶恋晨 2022-07-14 10:50 175阅读 0赞

# 出处：[http://www.jianshu.com/p/e40b329f5544][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][Spring IO]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][Link 1]，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/][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

![1240][]

Step1

![1240 1][]

Step2

![1240 2][]

Step3

![1240 3][]

Step4

创建项目完成后目录结构如下图所示

![1240 4][]

Step5

2.在POM文件中加入对Spring-Boot的依赖

<?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 /> 
        </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][http_host_PORT_users]"
 *  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<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

![1240 5][]

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！

[http_www.jianshu.com_p_e40b329f5544]: http://www.jianshu.com/p/e40b329f5544
[Spring Boot]: http://projects.spring.io/spring-boot
[Pivotal]: http://gopivotal.com/
[Spring IO]: http://spring.io/
[Link 1]: http://www.youtube.com/watch?v=jplkJIHPGos
[tweet]: https://twitter.com/rob_winch/status/364871658483351552
[http_projects.spring.io_spring-boot]: http://projects.spring.io/spring-boot/
[1240]: /images/20220714/4b7024451e3a49d6b49c750dd88b90f5.png
[1240 1]: /images/20220714/bef9c62912334e37a912016f000b1b89.png
[1240 2]: /images/20220714/7dc0de1a2a544ba0a22a8eebc08a1d35.png
[1240 3]: /images/20220714/222382e7bf2c496a87ca705d555937ce.png
[1240 4]: /images/20220714/679fdd9622b24214b7fe268fe19e0e96.png
[http_host_PORT_users]: http://host:PORT/users/%E5%AE%9E%E9%99%85%E7%9A%84%E7%94%A8%E6%88%B7%E5%90%8D
[1240 5]: /images/20220714/7a7f02581b6d4f988d72a9d37696eed7.png