以zookeeper为注册中心搭建spring cloud环境

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。