在spring cloud体系中，有多种手段实现注册中心，本例中采用zookeeper作为注册中心的角色。服务提供者向zookeeper注册，服务消费者从zookeeper中发现服务提供者的相关信息，从而远程调用服务提供方。
服务提供者
引入相关依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.2.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
</dependency>
<!-- 热部署工具 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Camden.SR2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
spring cloud与zookeeper的集成主要依赖spring-cloud-starter-zookeeper-discovery模块
定义DTO对象
public class UserDTO {
private Long id;
private String name;
private Date birthday;
/*
省略getter,setter方法
*/
}
定义服务提供接口
@RestController
public class ComputeController {
@Autowired
private DiscoveryClient client;
@RequestMapping(value = "/show", method = {RequestMethod.POST})
@ResponseBody
public UserDTO show(@RequestParam(value="id") Long id) {
ServiceInstance instance = client.getLocalServiceInstance();
UserDTO dto = new UserDTO();
dto.setId(id);
dto.setName("scott");
dto.setBirthday(new Date());
return dto;
}
}
在show方法中返回了dto对象。
配置文件
application.properties
server.port=8080
spring.application.name=server
bootstrap.properties
spring.cloud.zookeeper.connectString=192.168.179.200:2181
spring.cloud.zookeeper.discovery.instanceHost=127.0.0.1
spring.cloud.zookeeper.discovery.instancePort=${server.port}
启动项目
@SpringBootApplication
@EnableDiscoveryClient
public class AppStart {
public static void main(String[] args) {
SpringApplication.run(AppStart.class, args);
}
}
启动项目后可以在zookeeper中看到新增了/service节点，该节点有一个子节点server
服务消费者
引入与依赖项，这里用feign作为rest调用工具
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
</dependency>
<!-- 热部署工具 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
定义远程调用代理对象
@Component
@FeignClient(value="server",fallback=FeignConsumerClientHystrix.class)
public interface FeignConsumerClient {
@RequestMapping(method = RequestMethod.POST, value = "/show")
public String getUser(@RequestParam(value = "id") Long id);
}
以POST方式发起远程调用，调用地址根据@FeignClient中value值决定。
通过@FeignClient创建消费端代理对象。value指定服务名,该值与服务提供者的spring.application.name参数值相等，fallback指定异常处理类，异常处理类需实现本接口。
异常处理
@Component
public class FeignConsumerClientHystrix implements FeignConsumerClient{
@Override
public String getUser(@RequestParam("id") Long id) {
return "error";
}
}
所实现方法即为异常处理代码
注入代理对象，发起远程调用
@RestController
public class ClientController {
@Autowired
private FeignConsumerClient feignConsumerClient;
@RequestMapping(value = "/get", method = RequestMethod.GET)
@ResponseBody
public String add(@RequestParam(value = "id") Long id) {
return feignConsumerClient.getUser(id);
}
}
配置文件
application.properties
server.port=8081
spring.application.name=client
#断路器，断路器跳闸后等待多长时间重试
hystrix.command.default.circuitBreaker.sleepWindowInMilliseconds=1000
#断路器，请求发出后多长时间超时
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=5000
#ribbon连接到服务端的超时时间
ribbon.ConnectTimeout=5000
#ribbon连接到服务端后，多长时间没有获取到响应的超时时间
ribbon.ReadTimeout=5000
bootstrap.properties
spring.cloud.zookeeper.connectString=192.168.179.200:2181
#不向zookeeper注册
spring.cloud.zookeeper.discovery.register=false
服务消费者启动项目
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
@EnableHystrix
@EnableHystrixDashboard
@EnableCircuitBreaker
public class AppStart {
public static void main(String[] args) {
SpringApplication.run(AppStart.class, args);
}
}
启动项目后浏览器访问http://127.0.0.1:8081/get?id=xxx，正常情况即可看到由userDTO对象转换得到的json字符串。
后续补充spring cloud中的异常处理方法，故障转移，负载均衡等。
