Spring Cloud 微服务架构入门实战笔记

负载均衡和连接模板（Spring Ribbon&Feign）

DemoClient2Application.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class DemoClient2Application {
    public static void main(String[] args) {
        SpringApplication.run(DemoClient2Application.class, args);
    }
}

DemoController.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class DemoController {
    @Autowired
    private WordFeignClient wordFeignClient;

    @RequestMapping("/abc")
    public String getSentence() {
        return wordFeignClient.getWord() + wordFeignClient.getWord();
    }
}

WordFeignClient.java

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@FeignClient("mmb-eureka-subject")
public interface WordFeignClient {
    @RequestMapping(value = "/", method = RequestMethod.GET)
    String getWord();
}

application.properties

eureka.client.service-url.defaultZone=http://localhost:8181/eureka
server.port=8182
spring.application.name=mmb-eureka-client2
eureka.instance.prefer-ip-address=true
mmb-eureka-subject.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule

pom.xml

<?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.example</groupId>
    <artifactId>demo-client2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>demo-client2</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.6.1</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.6.1</version>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

网关（Spring Zuul）

ZuulDemoApplication.java

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.context.annotation.Bean;

@SpringCloudApplication
@EnableZuulProxy
public class ZuulDemoApplication {
    @Bean
    public SimpleFilter simpleFilter() {
        return new SimpleFilter();
    }

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

SimpleFilter.java

package com.example.demo;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import net.sf.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.http.HttpServletRequest;
import java.util.Map;

public class SimpleFilter extends ZuulFilter {
    private static Logger log = LoggerFactory.getLogger(SimpleFilter.class);

    @Override
    public String filterType() {
        return "pre";
    }

    @Override
    public int filterOrder() {
        return 1;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() {
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        Map<String,String[]> map=request.getParameterMap();
        JSONObject jsonMap= JSONObject.fromObject(map);
        log.info(String.format("%s request to %s Zuul==>params:%s", request.getMethod(), request.getRequestURL().toString(),jsonMap.toString()));
        return null;
    }
}

application.properties

#zuul.routes.sentence.path=/sentence2/**
#zuul.routes.sentence.serviceId=mmb-eureka-client2
#zuul.routes.sentence.url=http://localhost:8182/sentence
zuul.strip-prefix=false
server.port=8081
spring.application.name=mmb-zuul-server
eureka.client.service-url.defaultZone=http://localhost:8181/eureka

pom.xml

<?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.example</groupId>
    <artifactId>zuul-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>zuul-demo</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

配置中心与消息总线（Srping Config & Bus）

该配置中心设置是支持在 git 的统一配置管理，并支持 rabbitmq 的消息传播。也就是说该服务需要 rabbitmq 的环境。

配置中心

DemoConfigApplication.java

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.config.server.EnableConfigServer;

@SpringBootApplication
@EnableConfigServer
@EnableDiscoveryClient
public class DemoConfigApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoConfigApplication.class, args);
    }
}

application.properties

server.port=8888
spring.application.name=config-server
eureka.client.service-url.defaultZone=http://localhost:8181/eureka
eureka.instance.prefer-ip-address=true

bootstrap.properties

spring.cloud.config.server.git.uri=https://github.com/zhaoenweiex/config-repo.git
management.security.enabled=false
spring.cloud.config.server.git.basedir=target/config
spring.cloud.config.server.git.search-paths=configclient
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672

pom.xml

<?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.example</groupId>
    <artifactId>demo-config</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>demo-config</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-config-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bus-amqp</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

配置客户端

DemoClientApplication.java

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class DemoClientApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoClientApplication.class, args);
    }
}

DemoController.java

package com.example.demo;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.net.Inet4Address;
import java.net.UnknownHostException;

@RefreshScope
@RestController
public class DemoController {
    private static long timeStample=System.currentTimeMillis();

    @Value("${words}")
    private String wordsStr;

    @RequestMapping("/")
    public String getWord() {
        String[] wordArray = wordsStr.split(",");
        String address= null;
        try {
            address = Inet4Address.getLocalHost().getHostAddress();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        int i = (int)Math.round(Math.random() * (wordArray.length - 1));
        return wordArray[i]+timeStample+ address;
    }
}

application.properties

eureka.client.service-url.defaultZone=http://192.168.31.238:8181/eureka
server.port= ${PORT:${SERVER_PORT:0}}
spring.application.name=mmb-eureka-subject
eureka.instance.prefer-ip-address=true
spring.cloud.config.uri=http://localhost:8888
spring.cloud.config.profile=dev
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672

pom.xml

<?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.example</groupId>
    <artifactId>demo-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>demo-client</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-config-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bus-amqp</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

总结

本文展示了如何搭建基于 Spring Cloud 的微服务框架，包括了负责服务注册与发现的 Spring Eureka，负责基于客户端负载均衡的组件 Spring Ribbon，负责统一配置的 Spring Config，负责智能路由和网关的 Spring Zuul 以及消息更新的消息总线 Spring Bus，还有简化 Rest 连接的模板 Feign。

最后补充两点：

1. 在 Spring Cloud 中最为复杂和容易出错的的并非是业务代码开发，而是依赖与配置，所以关于.properties 或.yaml 都是使用 Spring Cloud 的必背基础。
2. 支撑业务的 Spring Boot 开发框架也是必不可少的基础知识。