一、简介

Spring Cloud Sleuth 主要功能就是在分布式系统中提供追踪解决方案，并且兼容支持了 zipkin，你只需要在pom文件中引入相应的依赖即可。

二、服务追踪分析

微服务架构上通过业务来划分服务的，通过REST调用，对外暴露的一个接口，可能需要很多个服务协同才能完成这个接口功能，如果链路上任何一个服务出现问题或者网络超时，都会形成导致接口调用失败。随着业务的不断扩张，服务之间互相调用会越来越复杂。

三、构建工程

基本知识讲解完毕，下面我们来实战，本文的案例主要有三个工程组成:一个server-zipkin,它的主要作用使用ZipkinServer 的功能，收集调用数据，并展示；一个service-hi,对外暴露hi接口；一个service-miya,对外暴露miya接口；这两个service可以相互调用；并且只有调用了，server-zipkin才会收集数据的，这就是为什么叫服务追踪了。

3.1 构建server-zipkin
在spring Cloud为F版本的时候，已经不需要自己构建Zipkin Server了，只需要下载jar即可，下载地址：

https://dl.bintray.com/openzipkin/maven/io/zipkin/java/zipkin-server/

也可以在这里下载：

链接: https://pan.baidu.com/s/1w614Z8gJXHtqLUB6dKWOpQ 密码: 26pf

下载完成jar 包之后，需要运行jar，如下：

java -jar zipkin-server-2.10.1-exec.jar

访问浏览器localhost:9494

3.2 创建service-zipkin
在其pom引入起步依赖spring-cloud-starter-zipkin，代码如下：

<?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><parent><groupId>com.gblfy</groupId><artifactId>sc-f-chapter9</artifactId><version>0.0.1-SNAPSHOT</version></parent><groupId>com.gblfy</groupId><artifactId>service-zipkin</artifactId><version>0.0.1-SNAPSHOT</version><name>service-zipkin</name><description>Demo project for Spring Boot</description><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-zipkin</artifactId></dependency></dependencies>
</project>

在其配置文件application.yml指定zipkin server的地址，头通过配置“spring.zipkin.base-url”指定：

server:port: 8988
spring:application:name: service-zipkinzipkin:base-url: http://localhost:9411/sender:type: websleuth:sampler:probability: 1
eureka:client:service-url:defaultZone: http://localhost:8761/eureka

通过引入spring-cloud-starter-zipkin依赖和设置spring.zipkin.base-url就可以了
启动类作以下修改:

@SpringBootApplication
@EnableDiscoveryClient
@EnableEurekaClient
public class ServiceZipkinApplication {public static void main(String[] args) {SpringApplication.run(ServiceZipkinApplication.class, args);}@Beanpublic RestTemplate getRestTemplate(){return new RestTemplate();}@Beanpublic Sampler defaultSampler() {return Sampler.ALWAYS_SAMPLE;}
}

对外暴露接口：

@RestController
public class ClientController {private static final Logger LOG = Logger.getLogger(ClientController.class.getName());@Autowiredprivate RestTemplate restTemplate;@RequestMapping("/hi")public String callHome(){LOG.log(Level.INFO, "calling trace service-hi  ");return restTemplate.getForObject("http://localhost:8989/miya", String.class);}@RequestMapping("/info")public String info(){LOG.log(Level.INFO, "calling trace service-hi ");return "i'm service-hi";}
}

33 创建service-miya
创建过程痛service-hi，引入相同的依赖，配置下spring.zipkin.base-url。

<?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><parent><groupId>com.gblfy</groupId><artifactId>sc-f-chapter9</artifactId><version>0.0.1-SNAPSHOT</version></parent><groupId>com.gblfy</groupId><artifactId>service-miya</artifactId><version>0.0.1-SNAPSHOT</version><name>service-miya</name><description>Demo project for Spring Boot</description><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-zipkin</artifactId></dependency></dependencies></project>

server:port: 8989
spring:zipkin:base-url: http://localhost:9411/sender:type: webapplication:name: service-miya
eureka:client:service-url:defaultZone: http://localhost:8761/eureka

启动类作以下修改:

@SpringBootApplication
@EnableDiscoveryClient
@EnableEurekaClient
public class ServiceMiyaApplication {public static void main(String[] args) {SpringApplication.run(ServiceMiyaApplication.class, args);}@Beanpublic RestTemplate getRestTemplate(){return new RestTemplate();}@Beanpublic Sampler defaultSampler() {return Sampler.ALWAYS_SAMPLE;}
}

对外暴露接口：

@RestController
public class ClientController {private static final Logger LOG = Logger.getLogger(ClientController.class.getName());@RequestMapping("/hi")public String home(){LOG.log(Level.INFO, "hi is being called");return "hi i'm miya!";}@RequestMapping("/miya")public String info(){LOG.log(Level.INFO, "info is being called");return restTemplate.getForObject("http://localhost:8988/info",String.class);}@Autowiredprivate RestTemplate restTemplate;
}

3.4 启动工程，演示追踪
依次启动上面的工程，打开浏览器访问：http://localhost:9411/，会出现以下界面：
略

访问：http://localhost:8989/miya，

浏览器出现：