springcloud 之Ribbon客户端负载均衡配置使用

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

ConfigBean代码
说明：主要代码，获取RestTemplate时，添加@LoadBalanced注解实现客户端负载均衡

package com.thr.springcloud.cfgbean;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;

/**
 * 注解@Configuration说明：相当于spring的applicationContext.xml
 * 即此时加了@Configuration注解的CfgBean类 等同于 applicationContext.xml
 * @author xiongxiaomeng
 */
@Configuration
public class CfgBean {

    /**
     * 使用RestTemplate调用Rest服务
     * @LoadBalanced 获取RestTemplate时，加入Ribbon的负载均衡的配置
     * @return Rest服务调用模板
     */
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
         return new RestTemplate();
    }
    
    /**
     * 定义负载均衡算法：
     * 默认：轮询，当前改成：随机
     * @return 随机算法
     */
    @Bean
    public IRule myRule() {
        return new RandomRule();
    }

}

package com.thr.springcloud.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.thr.springcloud.entities.User;

/**
 * 消费者端的RestController
 * 消费者端 都是 调用服务提供者的Controller，这里使用RestTemplate的方式调用
 * @author xiongxiaomeng
 *
 */
@RestController
public class UserController_Consumer {

    //未加入Eureka+Ribbon之前，采用ip+端口的访问方式
    //private static final String REST_URL_PREFIX = "http://localhost:8001";
    //加入Eureka+Ribbon之后，可以直接采用服务名的调用方式，无须再使用ip+端口的调用方式
    private static final String REST_URL_PREFIX = "http://THRCLOUD-DEPT";
    
    //使用restTemplate访问restful接口非常的简单粗暴无脑。(url, requestMap, ResponseBean.class)这三个参数分别代表
    @Autowired
    private RestTemplate _restTemplate;
    
    @RequestMapping(value="/consumer/user/add")
    public boolean add(User user) {
        return _restTemplate.postForObject(REST_URL_PREFIX + "/user/add", user, Boolean.class);
    }
    
    @RequestMapping(value="/consumer/user/get/{userId}")
    public User get(@PathVariable("userId") Long userId) {
        return _restTemplate.getForObject(REST_URL_PREFIX + "/user/get/" + userId, User.class);
    }
    
    @SuppressWarnings("unchecked")
    @RequestMapping(value="/consumer/user/list")
    public List<User> list() {
        return _restTemplate.getForObject(REST_URL_PREFIX + "/user/list", List.class);
    }
    
    @RequestMapping(value="/consumer/user/discovery")
    public Object discovery() {
        return _restTemplate.getForObject(REST_URL_PREFIX + "/user/discovery", Object.class);
    }
}