服务提供者

1:修改pom.xml文件，引入依赖包，代码如下：

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Edgware.SR4</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

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

2: 修改配置文件：

server.port=8000
spring.application.name=provider
eureka.instance.hostname=localhost 
eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/

3：在启动类上加上EnableEurekaClient注解

package com.ivan.provider;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * 
 * 功能描述:
 * 
 * @version 2.0.0
 * @author zhiminchen
 */
@SpringBootApplication
@EnableEurekaClient
public class App {
    public static void main(String[] args) {
        new SpringApplicationBuilder(App.class).run(args);
    }
}

4：编写具体服务提供Controller类

package com.ivan.provider.controller;

import java.util.Date;

import org.apache.http.client.utils.DateUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ProviderController {
    
    
    @RequestMapping(value="/provider", method={RequestMethod.GET})
    public String getProvider(){               
        String date = DateUtils.formatDate(new Date(), "yyyy-MM-dd hh:mm:ss");
        System.out.println(date);
        return date;
    }
    
    
}

服务消费者

1：修改pom.xml文件，与服务提供都不同的是这里需要引入spring-cloud-starter-ribbon 用于做负载均衡。服务提供都可能会部署多个实例，调用过程就涉及到负载均衡问题了。

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR4</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>
    </dependencies>

2：修改application.propertiest文件，跟服务端的配置差不多。

server.port=9000
spring.application.name=consumer
eureka.instance.hostname=localhost
eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/

3：编写启动类，注意这里需要 EnableDiscoveryClient注解。这个注解同样有将服务注册到Eureka注册中心的功能。

package com.ivan.consumer;

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

/**
 * 
 * 功能描述: 
 * 
 * @version 2.0.0
 * @author zhiminchen
 */

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

4：编写服务调用者，这里的Configuration注解用于将RestTemplate 类注入到Spring IOC容器中。LoadBalanced注解提供负载均衡。注意http://provider/provider 这个URL中第一个provider指的是服务提供者的应用名称，第二个provider指的是提供者提供的url。这里没有不需要指定具体服务的端口号

package com.ivan.consumer.controller;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@Configuration
public class ConsumerController {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }

    @RequestMapping(value = "/consumer", method = RequestMethod.GET)
    public String consumer() {
        RestTemplate template = getRestTemplate();
        // 根据应用名称调用服务
        String json = template.getForObject("http://provider/provider", String.class);
        return json;
    }
}