使用RestTemplate开发服务消费者
概念阐述
RestTemplate是Spring提供的RESTful访问接口,ServiceComb提供该接口的实现类用于服务的调用。
场景描述
用户使用ServiceComb提供的RestTemplate实例,可以使用自定义的URL进行服务调用,而不用关心服务的具体地址。
示例代码
RestTemplate实例通过调用RestTemplateBuilder.create()
方法获取,再使用该实例通过自定义的URL进行服务调用,代码如下:
- Spring MVC 客户端示例代码:
@Component
public class SpringmvcConsumerMain {
private static RestTemplate restTemplate = RestTemplateBuilder.create();
public static void main(String[] args) throws Exception {
init();
Person person = new Person();
person.setName("ServiceComb/Java Chassis");
String sayHiResult = restTemplate
.postForObject("cse://springmvc/springmvchello/sayhi?name=Java Chassis", null, String.class);
String sayHelloResult = restTemplate
.postForObject("cse://springmvc/springmvchello/sayhello", person, String.class);
System.out.println("RestTemplate consumer sayhi services: " + sayHiResult);
System.out.println("RestTemplate consumer sayhello services: " + sayHelloResult);
}
public static void init() throws Exception {
Log4jUtils.init();
BeanUtils.init();
}
}
- JAX RS 客户端示例代码:
@Component
public class JaxrsConsumerMain {
public static void main(String[] args) throws Exception {
init();
//其他都类似spring MVC示例的客户端代码,注意如果服务端只接收 GET 请求,要使用方法 getForObject()
RestTemplate restTemplate = RestTemplateBuilder.create();
String result = restTemplate.getForObject("cse://jaxrs/jaxrshello/saybye", String.class);
}
public static void init() throws Exception {
Log4jUtils.init();
BeanUtils.init();
}
}
说明:
- URL格式为:
cse://microserviceName/path?querystring
。以用SpringMVC开发微服务中定义的服务提供者为例,其微服务名称是springmvc
,basePath是/springmvchello
,那么URL中的microserviceName=springmvc
,请求sayhi时的path=springmvchello/sayhi
,所以示例代码中请求sayhi的URL是cse://springmvc/springmvchello/sayhi?name=Java Chassis
。具体代码示例如下 :
@RestSchema(schemaId = "springmvcHello")
@RequestMapping(path = "/springmvchello", produces = MediaType.APPLICATION_JSON)
//这里 path = “/springmvchello” 中的 springmvchello 就是 上述的basePath
public class SpringmvcHelloImpl implements Hello {
@Override
@RequestMapping(path = "/sayhi", method = RequestMethod.POST)
public String sayHi(@RequestParam(name = "name") String name) {
return "Hello " + name;
}
@Override
@RequestMapping(path = "/sayhello", method = RequestMethod.POST)
public String sayHello(@RequestBody Person person) {
return "Hello person " + person.getName();
}
}
下述代码是示例项目 SpringMVC 的 springmvc-provider 模块 中 resources 目录下 microservice.yaml
APPLICATION_ID: springmvc-sample
service_description:
name: springmvc # 这里就是定义的微服务名称
version: 0.0.2
servicecomb:
service:
registry:
address: http://127.0.0.1:30100
rest:
address: 0.0.0.0:8080
highway:
address: 0.0.0.0:7070
handler:
chain:
Provider:
default: bizkeeper-provider
cse:
service:
registry:
address: http://127.0.0.1:30100 #service center address
- 使用上述这种URL格式,ServiceComb框架会在内部进行服务发现、熔断容错等处理并最终将请求发送到服务提供者。