springcloud 服务调用的两种方式

spring-cloud调用服务有两种方式，一种是Ribbon+RestTemplate, 另外一种是Feign。

Ribbon是一个基于HTTP和TCP客户端的负载均衡器，其实feign也使用了ribbon一、Ribbon

1.1

新建模块client-a

pom文件

<?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">
    <parent>
        <artifactId>spring-cloud</artifactId>
        <groupId>com.feng</groupId>
        <version>0.0.1</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
<artifactId>client-a</artifactId>

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

</project>

新建bootstrap.yml

server:
  port: 8910
eureka:

client:

serviceUrl:

defaultZone: http://localhost:8010/eureka/


spring:

application:

name: client-a

ClientApplication, 这里我们需要注册一个RestTemplate，并且使用@LoadBalanced开启负载功能

/**
 * @author fengzp
 * @date 17/5/9
 * @email [e-mail]
 * @company 广州易站通计算机科技有限公司
 */
@SpringBootApplication
@EnableDiscoveryClient
public class ClientApplication {
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> main(String[] args) {
    SpringApplication.run(ClientApplication.</span><span style="color: #0000ff;">class</span><span style="color: #000000;">, args);
}

@Bean
@LoadBalanced
RestTemplate restTemplate(){
    </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span><span style="color: #000000;"> RestTemplate();
}

}

测试用的controller

/**
 * @author fengzp
 * @date 17/5/9
 * @email [e-mail]
 * @company 广州易站通计算机科技有限公司
 */
@RestController
public class TestController {
@Autowired
RestTemplate restTemplate;

@RequestMapping(</span><span style="color: #800000;">"</span><span style="color: #800000;">/hi</span><span style="color: #800000;">"</span><span style="color: #000000;">)
</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String hi(@RequestParam String id){
    </span><span style="color: #0000ff;">return</span> restTemplate.getForObject(<span style="color: #800000;">"</span><span style="color: #800000;">http://service-a/hi?id=</span><span style="color: #800000;">"</span>+id, String.<span style="color: #0000ff;">class</span><span style="color: #000000;">);
}

}

1.2

为了测试负载功能，这里要再新建一个模块service-b, 和上一篇的service-a的代码基本相同，只把端口修改了就可以。

把client-a和service-b都启动成功后，打开eureka中心应该看到：

1.3

打开http://localhost:8910/hi?id=123

可以看到服务已经成功调用。

然后刷新页面

看到端口已经改变，说明负载功能成功实现

二、feign

2.1

新建模块client-b

pom文件

<?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">
    <parent>
        <artifactId>spring-cloud</artifactId>
        <groupId>com.feng</groupId>
        <version>0.0.1</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
<artifactId>client-b</artifactId>

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

</project>

bootstrap.yml

server:
  port: 8911
eureka:

client:

serviceUrl:

defaultZone: http://localhost:8010/eureka/


spring:

application:

name: client-b

ClientApplication, 

/**
 * @author fengzp
 * @date 17/5/9
 * @email [e-mail]
 * @company 广州易站通计算机科技有限公司
 */
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class ClientApplication {
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> main(String[] args) {
    SpringApplication.run(ClientApplication.</span><span style="color: #0000ff;">class</span><span style="color: #000000;">, args);
}

}

这里新建一个ServiceAFeignClient来调用service-a服务

@Component
@FeignClient(value = "service-a") //这里的name对应调用服务的spring.applicatoin.name
public interface ServiceAFeignClient {
@RequestMapping(value </span>= <span style="color: #800000;">"</span><span style="color: #800000;">/hi</span><span style="color: #800000;">"</span><span style="color: #000000;">)
String hi(@RequestParam(</span><span style="color: #800000;">"</span><span style="color: #800000;">id</span><span style="color: #800000;">"</span><span style="color: #000000;">) String id);

}

Controller

@RestController
public class TestController {
@Autowired
ServiceAFeignClient serviceAFeignClient;

@RequestMapping(</span><span style="color: #800000;">"</span><span style="color: #800000;">/hi</span><span style="color: #800000;">"</span><span style="color: #000000;">)
</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String hi(@RequestParam String id){
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> serviceAFeignClient.hi(id);
}

}

2.2

运行后的结果应该是和ribbon的相同。

个人感觉使用feign比较舒服，代码比较简洁。