摘自官方說明：

Spring Cloud Netflix provides Netflix OSS integrations for Spring Boot apps through autoconfiguration and binding to the Spring Environment and other Spring programming model idioms. With a few simple annotations you can quickly enable and configure the common patterns inside your application and build large distributed systems with battle-tested Netflix components. The patterns provided include Service Discovery (Eureka), Circuit Breaker (Hystrix), Intelligent Routing (Zuul) and Client Side Load Balancing (Ribbon)..

通過上述可以了解到：

Eureka：服務(wù)發(fā)現(xiàn)
Hystrix：斷路器
Zuul：智能路由
Ribbon：客戶端負(fù)載均衡

先圖話后

Eureka：實(shí)際上在整個(gè)過程中維護(hù)者每個(gè)服務(wù)的生命周期。每一個(gè)服務(wù)都要被注冊到Eureka服務(wù)器上,，這里被注冊到Eureka的服務(wù)又稱為Client,。Eureka通過心跳來確定服務(wù)是否正常,。Eureka只做請求轉(zhuǎn)發(fā),。同時(shí)Eureka是支持集群的呦?。,?！
Zuul：類似于網(wǎng)關(guān)，反向代理,。為外部請求提供統(tǒng)一入口,。
Ribbon/Feign：可以理解為調(diào)用服務(wù)的客戶端。
Hystrix：斷路器,，服務(wù)調(diào)用通常是深層的,，一個(gè)底層服務(wù)通常為多個(gè)上層服務(wù)提供服務(wù)，那么如果底層服務(wù)失敗則會(huì)造成大面積失敗,，Hystrix就是就調(diào)用失敗后觸發(fā)定義好的處理方法,，從而更友好的解決出錯(cuò)。也是微服務(wù)的容錯(cuò)機(jī)制,。

多說不如看代碼

下面我們將搭建一個(gè)單Eureka服務(wù)器的案例,，我們將會(huì)注冊兩個(gè)微服務(wù)，并配置Zuul,。
目標(biāo)：
1.模擬外部請求,，訪問暴漏端口（Eureka監(jiān)聽端口）訪問其中一個(gè)內(nèi)部服務(wù)。
2.演示服務(wù)間如何通過Feign進(jìn)行調(diào)用,。
綜述：
我們要寫的包括：
一個(gè)Eureka服務(wù)器
兩個(gè)微服務(wù)

抽取出公共的POM部分,，讓我們專注重點(diǎn)

<project xmlns="http://maven./POM/4.0.0" xmlns:xsi="http://www./2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven./POM/4.0.0 http://maven./xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.xbz.eureka.demo</groupId>
    <artifactId>demo-eureka-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <java.version>1.7</java.version>
        <file.encoding>UTF-8</file.encoding>
    </properties>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-netflix</artifactId>
                <version>1.2.2.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <!-- 引入的依賴 -->
    </dependencies>
<build>
        <plugins>
            <plugin>  
                <artifactId>maven-compiler-plugin</artifactId>  
                <version>2.3.2</version>  
                <configuration>  
                    <source>${java.version}</source>  
                    <target>${java.version}</target>  
                    <encoding>${file.encoding}</encoding>  
                </configuration>  
            </plugin> 
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo./libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>
</project>
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<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zuul</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
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2.搞個(gè)Main啟動(dòng)類
@EnableEurekaServer
@EnableZuulProxy

package com.xbz.eureka.demo.server;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableEurekaServer
@EnableZuulProxy
public class EnurekaServer {
    public static void main(String[] args) {
        new SpringApplicationBuilder(EnurekaServer.class).web(true).run(args);
    }
}
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3.重點(diǎn)：application.yml

#單例模式啟動(dòng)Eureka Server
server:
  port: 8761 #啟動(dòng)端口
eureka:
  client:
    registerWithEureka: false #false:不作為一個(gè)客戶端注冊到注冊中心   
    fetchRegistry: false #為true時(shí)，可以啟動(dòng),，但報(bào)異常：Cannot execute request on any known server
zuul:
  prefix: /techouse #為zuul設(shè)置一個(gè)公共的前綴
  #ignoredServices: '*'
  routes:
    cloud-client: #隨便定義,，當(dāng)不存在serviceId時(shí)，默認(rèn)該值為serviceId（就是注冊服務(wù)的名稱,，屬性spring.application.name）
      path: /usersystem/** #匹配/techouse/usersystem/** 均路由到cloud-client
      serviceId: cloud-client #指定路由到的serviceId
ribbon:
  eureka:
    enabled: false #配置zuul路由時(shí)用將此屬性設(shè)置為false

cloud-client:
  ribbon:
    listOfServers: 127.0.0.1:8800 #為cloud-client服務(wù)指定一組服務(wù)地址,，應(yīng)該是用于負(fù)載均衡
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<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
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    這個(gè)服務(wù)我們在上面的application.yml中配置了，等下我們就可以用Eureka服務(wù)器地址訪問此服務(wù),。
該服務(wù)包含一個(gè)HellController,，和ServerApplication(啟動(dòng)類)
HelloController.java

package com.xbz.eureka.demo.client.controller;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;

@RestController
public class HelloController {
    @RequestMapping("/hello/{fallback}")
    @HystrixCommand(fallbackMethod="helloFallbackMethod")/*調(diào)用方式失敗后調(diào)用helloFallbackMethod*/
    public String hello(@PathVariable("fallback") String fallback){
        if("1".equals(fallback)){
            throw new RuntimeException("...");
        }
        return "hello";
    }

    public String helloFallbackMethod(String fallback){
        return "fallback 參數(shù)值為:"+fallback;
    }
}
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ServerApplication.java
@EnableEurekaClient，確保該應(yīng)用注冊到Eureka服務(wù)器
@EnableHystrix 斷路器生效

package com.xbz.eureka.demo.client;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;

@SpringBootApplication
@EnableEurekaClient
@EnableHystrix
public class ServiceApplication {
    public static void main(String[] args) {
        SpringApplication.run(ServiceApplication.class, args);
    }
}
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重要的application.xml

server:
  port: 8800
spring:
  application:
    name: cloud-client #為你的應(yīng)用起個(gè)名字,，該名字將注冊到eureka注冊中心
eureka:
  instance:
    statusPageUrlPath: ${management.context-path}/info
    healthCheckUrlPath: ${management.context-path}/health
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/ #去哪里注冊,，eureka服務(wù)地址
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服務(wù)cluod-client-consumer
這個(gè)服務(wù)要調(diào)用cloud-client服務(wù)中的/hello/{fallback}方法
使用@Feign(“服務(wù)名稱”),接口中隨便定義方法,，然后@RequestMapping(“/hello/{fallback}”)即可，內(nèi)部調(diào)用就是如此簡單,。
涉及HelloService（演示如何使用@Feign）調(diào)用服務(wù),。HelloController演示調(diào)用服務(wù)的輸出結(jié)果，以及ConsumerApplication啟動(dòng)類,。
HelloService.java

package com.xbz.eureka.demo.consumer;

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

@FeignClient("cloud-client")
public interface HelloService {
    @RequestMapping("/hello/{fallback}")
    public String hello(@PathVariable("fallback") String fallback);
}
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HelloController.java

package com.xbz.eureka.demo.consumer;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
    @Autowired
    private HelloService helloServcie;
    @RequestMapping("/test/{fallback}")
    public String hello(@PathVariable("fallback") String fallback){
        String res=helloServcie.hello(fallback);
        return "調(diào)用服務(wù)結(jié)果為"+res;
    }
}
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啟動(dòng)類ConsumerApplication.java
@EnableEurekaClient注冊到Eureka
@EnableFeignClients 內(nèi)部使用Feign調(diào)用服務(wù)
@EnableZuulProxy 必須要有這個(gè)注解

package com.xbz.eureka.demo.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableEurekaClient
@EnableZuulProxy
@EnableFeignClients
public class ConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConsumerApplication.class, args);
    }
}
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重要application.xml

server:
 port: 8080
spring:
  application:
   name: cloud-consumer #為你的應(yīng)用起個(gè)名字,，該名字將注冊到eureka注冊中心
eureka:
  instance:
    statusPageUrlPath: ${management.context-path}/info
    healthCheckUrlPath: ${management.context-path}/health
  client:
    serviceUrl:
      defaultZone: http://hadoopMaster:8761/eureka/ #去哪里注冊，eureka服務(wù)地址
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