微服务 feign 负载均衡 https

微服务之间的调用，如果需要进行负载均衡，可以使用Ribbon和Feign的结合。同样需要在Feign的配置中启用HTTPS支持，并且配置Ribbon的负载均衡策略。具体步骤如下：

1. 引入Ribbon和Feign的依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

2. 配置Feign和Ribbon的HTTPS支持和负载均衡策略

@Configuration
public class FeignConfig {

    @Autowired
    private ObjectFactory<HttpMessageConverters> messageConverters;

    @Bean
    public Client feignClient() {
        return new Client.Default(getSSLSocketFactory(), null);
    }

    private SSLSocketFactory getSSLSocketFactory() {
        try {
            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, new TrustManager[] { new X509TrustManager() {
                public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {}
                public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {}
                public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[0]; }
            } }, new SecureRandom());
            return sslContext.getSocketFactory();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Bean
    public Decoder feignDecoder() {
        return new ResponseEntityDecoder(new SpringDecoder(messageConverters));
    }

    @Bean
    public IRule ribbonRule() {
        return new RandomRule();
    }

    @Bean
    public IPing ribbonPing() {
        return new PingUrl(false, "/health");
    }

    @Bean
    public ServerList<Server> ribbonServerList() {
        return new ConfigurationBasedServerList();
    }

    @Bean
    public OkHttpClient ribbonOkHttpClient() {
        return new OkHttpClient.Builder().sslSocketFactory(getSSLSocketFactory(), new X509TrustManager() {
            public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
            }
            public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
            }
            public X509Certificate[] getAcceptedIssuers() {
                return new X509Certificate[0];
            }
        }).build();
    }

    @Bean
    public RibbonClientConfiguration ribbonClientConfiguration(IClientConfig config, ILoadBalancer loadBalancer, ServerList<Server> serverList, ServerListFilter<Server> serverListFilter, IRule rule, IPing ping, RetryHandler retryHandler, OkHttpClient ribbonOkHttpClient) {
        return new RibbonClientConfiguration(config, loadBalancer, serverList, serverListFilter, rule, ping, retryHandler, ribbonOkHttpClient);
    }

}

其中，`ribbonRule`方法配置了Ribbon的负载均衡策略，这里采用了随机策略，可以根据实际需求进行调整。

3. 在Feign的接口中使用`https`协议和负载均衡地址

@FeignClient(name = "example", configuration = ExampleConfig.class)
public interface ExampleClient {

    @GetMapping("/api")
    String get();
    
}

其中，`configuration`参数指定了配置类，用于配置Ribbon相关的设置。

4. 在配置类中配置Ribbon的信息

@Configuration
public class ExampleConfig {

    @Bean
    public IRule ribbonRule() {
        return new RandomRule();
    }

    @Bean
    public IPing ribbonPing() {
        return new PingUrl(false, "/health");
    }

    @Bean
    public ServerList<Server> ribbonServerList(IClientConfig config) {
        return new ConfigurationBasedServerList();
    }

}

其中，`ribbonRule`方法和`ribbonPing`方法分别配置了Ribbon的负载均衡策略和健康检查的地址，`ribbonServerList`方法返回一个`ServerList`对象，用于配置可用的服务列表。

5. 在微服务中使用Feign进行调用

@RestController
public class ExampleController {

    @Autowired
    private ExampleClient exampleClient;

    @GetMapping("/example")
    public String get() {
        return exampleClient.get();
    }
    
}

这样就可以在微服务中使用Feign调用HTTPS接口，并且进行负载均衡了。