微服务：实现服务发现与服务注册

一.服务发现的方式：

              1.客户端发现：Eureka、ZooKeeper(存在缺陷)原因：http://blog.csdn.net/whereismatrix/article/details/53305045

              2.服务端发现：consul+nginx

描述：Eureka是Netflix开发的服务发现框架，本身是一个基于REST的服务，主要用于定位运行在AWS域中的中间层服务，以达到负载均衡和中间层服务故障转移的目的。SpringCloud将它集成在其子项目spring-cloud-netflix中，一实现SpringCloud的服务发现功能

二.服务注册的功能

1.服务注册表：服务注册是一个记录当前可用的微服务实例的网络信息数据库，是服务发现机制的主要核心，服务注册表查询api、管理api，使用查询api获得可用服务的实例，使用管理api实现注册、注销

2.服务注册：节点启动后，会在Eureka Server中进行注册，这样EurekaServer中的服务注册表中将会存储所有可用服务节点的信息，服务节点的信息可以在界面中直观的看到。

三.实现一个Eurka Serve【microservice-discovery-eureka】

1.添加Eureka的maven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.example</groupId>
    <artifactId>microservice-discovery-eureka</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>microservice-discovery-eureka</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </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.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- 身份验证
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</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>

2.启动类：使用@EnableEurekaServer注解

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@EnableEurekaServer//注册成一个服务注册中心，给其他微服务应用进行提供会话
@SpringBootApplication
public class MicroserviceDiscoveryEurekaApplication {

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

3.application.properties的配置项

security.basic.enabled=true
security.user.name=user
security.user.password=test123456
server.port=8761
eureka.instance.hostname=localhost
eureka.client.registerWithEureka=false
eureka.client.fetchRegistry=false
#添加身份验证

eureka.client.serviceUrl.defaultZone=http://${security.user.name}:${security.user.password}@${eureka.instance.hostname}:${server.port}/eureka/
#默认

eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/
spring.application.name=cloud-eureka-server

4.启动【microservice-discovery-eureka】

四.实现一个【microservice-provider-user】

1.添加Eureka的maven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.example</groupId>
    <artifactId>microservice-provider-user</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>microservice-provider-user</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </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.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </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>

2.启动类：使用@EnableEurekaClient注解

package com.example;

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

@SpringBootApplication
@EnableAutoConfiguration
@EnableEurekaClient//注册一个服务注册应用
public class MicroserviceProviderUserApplication {

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

3.application.properties的配置项

server.port=9090
#服务注册表中描述应用的名称

spring.application.name=microservice-provider-user
security.user.name=user
security.user.password=test123456
#eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka-server-1.4.6/eureka/ 

#添加身份验证

eureka.client.serviceUrl.defaultZone=http://${security.user.name}:${security.user.password}@localhost:8761/eureka/
eureka.instance.appname=microservice.client.user
#eureka.client.registerWithEureka=true
#eureka.client.fetchRegistry=true

4.启动【microservice-provider-user】

描述：先启动服务发现，再启动服务注册类，刷新服务发现管理页面

五.对Eureka服务的身份验证(Authenticating with the Eureka Server)

1.修改应用maven依赖(服务注册、服务发现)

<!-- 身份验证-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>

2.添加身份验证

服务发现application.properties的配置项

security.basic.enabled=true
security.user.name=user
security.user.password=test123456
server.port=8761
eureka.instance.hostname=localhost
eureka.client.registerWithEureka=false
eureka.client.fetchRegistry=false
eureka.client.serviceUrl.defaultZone=http://${security.user.name}:${security.user.password}@${eureka.instance.hostname}:${server.port}/eureka/
spring.application.name=cloud-eureka-server

3.重新启动，访问服务发现管理页面

4.服务注册应用也需要用到身份验证，否则注册不了

服务注册application.properties的配置项

server.port=9090
spring.application.name=microservice-provider-user
security.user.name=user
security.user.password=test123456
eureka.client.serviceUrl.defaultZone=http://${security.user.name}:${security.user.password}@localhost:8761/eureka/
eureka.instance.appname=microservice.client.user
#eureka.client.registerWithEureka=true
#eureka.client.fetchRegistry=true