• 新建一個簡單的Springboot專案——ribbon-service，然後編寫一個方法，開啟兩個埠啟動專案。

@RequestMapping(value = "/person", method = RequestMethod.GET, 
            produces = MediaType.APPLICATION_JSON_VALUE)
    public Person getPerson(HttpServletRequest request){
        Person p = new Person();
        p.setId(1);
        p.setName
 
("小米");
        p.setMessage(request.getRequestURL().toString());
        return p;
    }

• 新建一個簡單的maven專案，通過簡單的main方法訪問ribbon-service：

public static void main(String[] args) throws Exception {
        ConfigurationManager.getConfigInstance().setProperty(
                "my-client.ribbon.listOfServers"
 
, "localhost:8080,localhost:8081"); 
        RestClient client = (RestClient) ClientFactory.getNamedClient("my-client"); 
        HttpRequest request = HttpRequest.newBuilder().uri(("/person")).build();
        for(int i = 0;i<10;i++){
            HttpResponse response = client.executeWithLoadBalancer(request); 
 

            String json = response.getEntity(String.class);
            System.out.println(json);
        }

    }

• 輸出，可以看到Ribbon的預設策略就是RoundRobinRule（輪換）：

{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}

• 接下來自定義策略，新建一個類，實現IRule，重寫choose():

public class MyRule implements IRule {

    private ILoadBalancer lb;

    public Server choose(Object key) {
        Random r= new Random();
        int num = r.nextInt(10);

        List<Server> servers =  lb.getAllServers();

        if(num > 7){
            return getServerByPost(servers,8081);
        }else{
            return getServerByPost(servers,8080);
        }

    }

    private Server getServerByPost(List<Server> servers,int port){
        for(Server s:servers){
            if(s.getPort() == port){
                return s;
            }
        }
        return null;
    }

    public void setLoadBalancer(ILoadBalancer lb) {
        this.lb=lb;

    }

    public ILoadBalancer getLoadBalancer() {
        return this.lb;
    }

}

• main方法使用MyRule策略：

ConfigurationManager.getConfigInstance().setProperty(
                "my-client.ribbon.NFLoadBalancerRuleClassName", MyRule.class.getName());

• 測試，可以看到，呼叫8080埠比8081埠的多：

{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8080/person"}
{"id":1,"name":"小米","message":"http://localhost:8081/person"}