带你玩转 springCloud - 第6篇ribbon自定义负载方式

1．创建MySelfRule配置类

@Configuration
public class MySelfRule
{
@Bean
public IRule myRule()
{
//return new RandomRule();// Ribbon默认是轮询，我自定义为随机
//return new RoundRobinRule();// Ribbon默认是轮询，我自定义为随机

return new RandomRule_ZY();// 我自定义为每台机器5次
}
}           

2．创建RandomRule_ZY类

public class RandomRule_ZY extends AbstractLoadBalancerRule
{

// total = 0 // 当total==5以后，我们指针才能往下走，
// index = 0 // 当前对外提供服务的服务器地址，
// total需要重新置为零，但是已经达到过一个5次，我们的index = 1
// 分析：我们5次，但是微服务只有8001 8002 8003 三台，OK？
//

private int total = 0; // 总共被调用的次数，目前要求每台被调用5次
private int currentIndex = 0; // 当前提供服务的机器号

public Server choose(ILoadBalancer lb, Object key)
{
if (lb == null) {
return null;
}
Server server = null;

while (server == null) {
if (Thread.interrupted()) {
return null;
}
List<Server> upList = lb.getReachableServers();
List<Server> allList = lb.getAllServers();

int serverCount = allList.size();
if (serverCount == 0) {
/*
* No servers. End regardless of pass, because subsequent passes only get more
* restrictive.
*/
return null;
}
// int index = rand.nextInt(serverCount);// java.util.Random().nextInt(3);
// server = upList.get(index);

// private int total = 0; // 总共被调用的次数，目前要求每台被调用5次
// private int currentIndex = 0; // 当前提供服务的机器号
if(total < 5)
{
server = upList.get(currentIndex);
total++;
}else {
total = 0;
currentIndex++;
if(currentIndex >= upList.size())
{
currentIndex = 0;
}
}

if (server == null) {
/*
* The only time this should happen is if the server list were somehow trimmed.
* This is a transient condition. Retry after yielding.
*/
Thread.yield();
continue;
}

if (server.isAlive()) {
return (server);
}

// Shouldn't actually happen.. but must be transient or a bug.
server = null;
Thread.yield();
}

return server;

}

@Override
public Server choose(Object key)
{
return choose(getLoadBalancer(), key);
}

@Override
public void initWithNiwsConfig(IClientConfig clientConfig)
{
// TODO Auto-generated method stub

}

}           

3．创建ConfigBean 类

@Configuration
//boot -->spring applicationContext.xml --- @Configuration配置 ConfigBean = applicationContext.xml
public class ConfigBean{
@Bean
@LoadBalanced//Spring Cloud Ribbon是基于Netflix Ribbon实现的一套客户端 负载均衡的工具。
public RestTemplate getRestTemplate()
{
return new RestTemplate();
}

@Bean
public IRule myRule()
{
//return new RoundRobinRule();
//return new RandomRule();//达到的目的，用我们重新选择的随机算法替代默认的轮询。
return new RetryRule();
}
}