前言介绍
为什么会有路由层?因为在微服务架构设计中,往往并不会直接将服务暴漏给调用端,而是通过调用路由层进行业务隔离,以达到不同的业务调用对应的服务模块。
Spring Cloud Zuul
Spring Cloud Zuul 路由是微服务架构的不可或缺的一部分,提供动态路由、监控、弹性、安全等的边缘服务。Zuul 是 Netflix 出品的一个基于 JVM 路由和服务端的负载均衡器。
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环境准备
- jdk 1.8、idea2018、Maven3
- Spring Boot 2.0.6.RELEASE
- Spring Cloud Finchley.SR2
代码示例
itstack-demo-springcloud-08 ├── itstack-demo-springcloud-eureka-client │ └── src │ └── main │ ├── java │ │ └── org.itstack.demo │ │ ├── web │ │ │ └── EurekaClientController.java │ │ └── EurekaClientApplication.java │ └── resources │ └── application.yml ├── itstack-demo-springcloud-eureka-server │ └── src │ └── main │ ├── java │ │ └── org.itstack.demo │ │ └── EurekaServerApplication.java │ └── resources │ └── application.yml ├── itstack-demo-springcloud-hystrix-feign │ └── src │ └── main │ ├── java │ │ └── org.itstack.demo │ │ ├── service │ │ │ ├── hystrix │ │ │ │ └── FeignServiceHystrix.java │ │ │ └── FeignService.java │ │ ├── web │ │ │ └── FeignController.java │ │ └── FeignApplication.java │ └── resources │ └── application.yml ├── itstack-demo-springcloud-hystrix-ribbon │ └── src │ └── main │ ├── java │ │ └── org.itstack.demo │ │ ├── service │ │ │ └── RibbonService.java │ │ ├── web │ │ │ └── RibbonController.java │ │ └── RibbonApplication.java │ └── resources │ └── application.yml └── itstack-demo-springcloud-zuul └── src └── main ├── java │ └── org.itstack.demo │ └── ZuulApplication.java └── resources └── application.yml
itstack-demo-springcloud-eureka-client | 服务提供方
提供一个查询用户信息的简单方法,在配置文件中通过修改端口启动2次,模拟双实例应用,为调用方负载做准备。
web/EurekaClientController.java & 注意@EnableEurekaClient用于向注册中心提供服务
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @EnableEurekaClient @RestController public class EurekaClientController { @Value("${server.port}") private int port; @RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET) public String queryUserInfo(@RequestParam String userId) { return "Hi 微信公众号:bugstack虫洞栈 | " + userId + " >: from eureka client port: " + port; } }
EurekaClientApplication.java & 服务启动类
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @SpringBootApplication public class EurekaClientApplication { public static void main(String[] args) { SpringApplication.run(EurekaClientApplication.class, args); } }
pom.xml & 配置文件指向注册中心
server: port: 8001 spring: application: name: itstack-demo-springcloud-eureka-client eureka: client: serviceUrl: defaultZone: http://localhost:7397/eureka/
itstack-demo-springcloud-eureka-server | 单个服务注册中心
服务注册中心用于承载接口提供方向上注册,同时正在调用方链接后可以获取指定应用的服务实例。
EurekaServerApplication.java & 通过注解@EnableEurekaServer启动服务注册与发现中心
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @SpringBootApplication @EnableEurekaServer public class EurekaServerApplication { public static void main(String[] args) { SpringApplication.run( EurekaServerApplication.class, args ); } }
pom.xml & 服务注册中心
server: port: 7397 eureka: instance: hostname: localhost client: registerWithEureka: false fetchRegistry: false serviceUrl: defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ spring: application: name: itstack-demo-springcloud-eureka-server
itstack-demo-springcloud-feign | Feign服务调用方
Feign 是一个声明式的 Web Service 客户端,它的目的就是让 Web Service 调用更加简单。它整合了 Ribbon 和 Hystrix,从而让我们不再需要显式地使用这两个组件。Feign 还提供了 HTTP 请求的模板,通过编写简单的接口和插入注解,我们就可以定义好 HTTP 请求的参数、格式、地址等信息。接下来,Feign 会完全代理 HTTP 的请求,我们只需要像调用方法一样调用它就可以完成服务请求。
Feign 具有如下特性:
可插拔的注解支持,包括 Feign 注解和 JAX-RS 注解
支持可插拔的 HTTP 编码器和解码器
支持 Hystrix 和它的 Fallback
支持 Ribbon 的负载均衡
支持 HTTP 请求和响应的压缩
service/FeignService.java | 注解方式调用,方便易用。@FeignClient会在调用时进行解析服务到具体的http://ip:port/
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @FeignClient(value = "itstack-demo-springcloud-eureka-client", fallback = FeignServiceHystrix.class) public interface FeignService { @RequestMapping(value = "/api/queryUserInfo", method = RequestMethod.GET) String queryUserInfo(@RequestParam String userId); }
service/hystrix/FeignServiceHystrix.java | 提供熔断服务,当发生异常时主动返回预定结果
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @Component public class FeignServiceHystrix implements FeignService { @Override public String queryUserInfo(String userId) { return "queryUserInfo by userId:" + userId + " err!from feign hystrix"; } }
web/FeignController.java | 使用接口提供服务 From Feign
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @RestController public class FeignController { @Resource private FeignService ribbonService; @RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET) public String queryUserInfo(@RequestParam String userId) { return ribbonService.queryUserInfo(userId) + " From Feign"; } }
FeignApplication.java | 注解@EnableEurekaClient、@EnableFeignClients、@EnableDiscoveryClient获取调用注册中心服务
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @SpringBootApplication @EnableEurekaClient @EnableDiscoveryClient @EnableFeignClients @EnableHystrix public class FeignApplication { public static void main(String[] args) { SpringApplication.run(FeignApplication.class, args); } }
application.yml | eureka服务配置,从注册中心获取可用服务。开启hystrix=true
server: port: 9001 spring: application: name: itstack-demo-springcloud-feign eureka: client: serviceUrl: defaultZone: http://localhost:7397/eureka/ feign.hystrix.enabled: true
itstack-demo-springcloud-ribbon | Ribbon服务调用方
Ribbon是一个基于 HTTP 和 TCP 的客户端负载均衡器。它可以通过在客户端中配置 ribbonServerList 来设置服务端列表去轮询访问以达到均衡负载的作用。
当 Ribbon 与 Eureka 联合使用时,ribbonServerList 会被 DiscoveryEnabledNIWSServerList 重写,扩展成从 Eureka 注册中心中获取服务实例列表。同时它也会用 NIWSDiscoveryPing 来取代 IPing,它将职责委托给 Eureka 来确定服务端是否已经启动。
service/RibbonService.java | 接口式硬编码调用不太易于维护,因此也是比较少用的方式。hystrix实际通过getFallback()返回熔断结果
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @Service public class RibbonService { @Autowired private RestTemplate restTemplate; @HystrixCommand(fallbackMethod = "queryUserInfoFallback") public String queryUserInfo(String userId) { return restTemplate.getForObject("http://ITSTACK-DEMO-SPRINGCLOUD-EUREKA-CLIENT/api/queryUserInfo?userId=" + userId, String.class); } /** * Specifies a method to process fallback logic. * A fallback method should be defined in the same class where is HystrixCommand. * Also a fallback method should have same signature to a method which was invoked as hystrix command. * for example: * <code> * @HystrixCommand(fallbackMethod = "getByIdFallback") * public String getById(String id) {...} * * private String getByIdFallback(String id) {...} * </code> * Also a fallback method can be annotated with {@link HystrixCommand} * <p/> * default => see {@link com.netflix.hystrix.contrib.javanica.command.GenericCommand#getFallback()} * * @return method name * * getFallback() * * @Override * protected Object getFallback() { * final CommandAction commandAction = getFallbackAction(); * if (commandAction != null) { * try { * return process(new Action() { * @Override * Object execute() { * MetaHolder metaHolder = commandAction.getMetaHolder(); * Object[] args = createArgsForFallback(metaHolder, getExecutionException()); * return commandAction.executeWithArgs(metaHolder.getFallbackExecutionType(), args); * } * }); * } catch (Throwable e) { * LOGGER.error(FallbackErrorMessageBuilder.create() * .append(commandAction, e).build()); * throw new FallbackInvocationException(unwrapCause(e)); * } * } else { * return super.getFallback(); * } * } */ public String queryUserInfoFallback(String userId) { return "queryUserInfo by userId:" + userId + " err!from ribbon hystrix"; } }
web/RibbonController.java | 使用接口提供服务 From Ribbon
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @RestController public class RibbonController { @Resource private RibbonService ribbonService; @RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET) public String queryUserInfo(@RequestParam String userId) { return ribbonService.queryUserInfo(userId) + " From Ribbon"; } }
RibbonApplication.java | 通过注解@LoadBalanced注册rest模版,用于Ribbon接口调用。并启动@EnableHystrix
/** * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @SpringBootApplication @EnableEurekaClient @EnableDiscoveryClient @EnableHystrix public class RibbonApplication { public static void main(String[] args) { SpringApplication.run(RibbonApplication.class, args); } @Bean @LoadBalanced RestTemplate restTemplate() { return new RestTemplate(); } }
application.yml | eureka服务配置,从注册中心获取可用服务
server: port: 9002 spring: application: name: itstack-demo-springcloud-ribbon eureka: client: serviceUrl: defaultZone: http://localhost:7397/eureka/
itstack-demo-springcloud-zuul | Zull路由层
Spring Cloud Zuul 路由是微服务架构的不可或缺的一部分,提供动态路由、监控、弹性、安全等的边缘服务。Zuul 是 Netflix 出品的一个基于 JVM 路由和服务端的负载均衡器。
ZuulApplication.java & 路由服务启动
/** * 微信公众号:bugstack虫洞栈 | 专注原创技术专题案例 * 论坛:http://bugstack.cn * Create by 付政委 on @2019 */ @SpringBootApplication @EnableZuulProxy @EnableEurekaClient @EnableDiscoveryClient public class ZuulApplication { public static void main(String[] args) { SpringApplication.run(ZuulApplication.class, args); } }
pom.mxl & 路由配置
server: port: 10001 spring: application: name: itstack-demo-ddd-zuul eureka: client: serviceUrl: defaultZone: http://localhost:7397/eureka/ # http://localhost:10001/route-a/api/queryUserInfo?userId=111 # http://localhost:10001/route-b/api/queryUserInfo?userId=111 zuul: routes: api-a: path: /route-a/** serviceId: itstack-demo-springcloud-feign api-b: path: /route-b/** serviceId: itstack-demo-springcloud-ribbon
测试验证
-
分别启动如下系统模拟;
- itstack-demo-springcloud-eureka-server 服务注册发现中心
- itstack-demo-springcloud-eureka-client 测试接口提供方
- itstack-demo-springcloud-hystrix-feign 接口调用方Feign
- itstack-demo-springcloud-hystrix-ribbon 接口调用方Ribbon
- itstack-demo-springcloud-zuul 路由服务
-
测试接口
- 访问Feign、Ribbon接口,验证服务是否可用;http://localhost:9001/api/queryUserInfo?userId=111、http://localhost:9002/api/queryUserInfo?userId=111
- 访问路由接口A;http://localhost:10001/route-a/api/queryUserInfo?userId=111
- 访问路由接口B;http://localhost:10001/route-b/api/queryUserInfo?userId=111
综上总结
- zuul目前SpringCloud结合的是zuul 1, Netflix 已经发布了 Zuul 2但目前还未整合
- SpringCloud还有自己的网关服务;Spring Cloud Gateway
- 通过最上层的路由功能可以很方便的隔离业务,但是路由层一定是高可用的,否则路由瘫痪整个服务将不可用