SpringCloud系列——Feign+Ribbon配置实战篇

一般情况下，Feign和Ribbon我们都是结合使用的。Feign是网络请求客户端，Ribbon用于负载均衡，feign底层实现了ribbon
 

默认配置

默认配置入口

//RibbonClientConfiguration.java
@Bean
@ConditionalOnMissingBean
public IClientConfig ribbonClientConfig() {
	DefaultClientConfigImpl config = new DefaultClientConfigImpl();
	config.set(CommonClientConfigKey.ConnectTimeout, 1000);
	config.set(CommonClientConfigKey.ReadTimeout, 1000);
	return config;
}

1.文件配置

全局配置：

ribbon.ConnectTimeout=1000
ribbon.ReadTimeout=3000

单个配置：

feignClientName.ribbon.ConnectTimeout=1000
feignClientName.ribbon.ReadTimeout=3000

2.代码注解配置

新增配置类:

@Configuration
public class CustomConfiguration {
    @Bean
    public Request.Options feignRequestOptions() {
        return new Request.Options(connectTimeoutMillis, readTimeoutMillis);
    }
}

在被FeignClient注解的类中添加配置:

@FeignClient(name = "user-api", configuration = CustomConfiguration.class)
public interface TestFeign {
    @GetMapping(value = "/getName")
    @ApiOperation(value = "测试数据", httpMethod = "GET")
    String getName();
}

其中，代码注解配置比文件配置方式优先级更高。

3.重试次数设置

Feign默认是不会进行重试的！

//FeignClientsConfiguration.java
@Bean
@ConditionalOnMissingBean
public Retryer feignRetryer() {
	return Retryer.NEVER_RETRY;
}

 自定义重试策略

@Bean
public Retryer feignRetryer() {
    return new Retryer.Default(period, maxPeriod, maxAttempts);
}

同时Feign的HTTP客户端支持三种框架：

        HttpURLConnection、HttpClient、OkHttp；Feign使用的默认客户端是HttpURLConnection，且没有SSL认证：

4.切换网络请求客户端

//feign.Client.java
public interface Client{
	public static class Default implements Client {
		HttpURLConnection convertAndSend(Request request, Options options) throws IOException {
			final HttpURLConnection connection =
          (HttpURLConnection) new URL(request.url()).openConnection();
            ......
		}
	}
}

切换成Apache的HttpClient

新增依赖：这里的版本号，要跟io.github.openfeign:feign-core的版本，保持一致。

    io.github.openfeign
    feign-httpclient
    10.1.0

新增配置：

feign.compression.response.enabled=true

这里设置为true之后，spring容器就会去加载自定义的httpClient：

//HttpClientFeignLoadBalancedConfiguration.java
//若为true，就会来加载这里
@Bean
@ConditionalOnProperty(value = "feign.compression.response.enabled", havingValue = "true")
public CloseableHttpClient customHttpClient(HttpClientConnectionManager httpClientConnectionManager,
									  FeignHttpClientProperties httpClientProperties) {
	HttpClientBuilder builder = HttpClientBuilder.create().disableCookieManagement().useSystemProperties();
	this.httpClient = createClient(builder, httpClientConnectionManager, httpClientProperties);
	return this.httpClient;
}
//若为false，加载默认的HttpURLConnection
@Bean
@ConditionalOnProperty(value = "feign.compression.response.enabled", havingValue = "false", matchIfMissing = true)
public CloseableHttpClient httpClient(ApacheHttpClientFactory httpClientFactory, HttpClientConnectionManager httpClientConnectionManager,
									  FeignHttpClientProperties httpClientProperties) {
	this.httpClient = createClient(httpClientFactory.createBuilder(), httpClientConnectionManager, httpClientProperties);
	return this.httpClient;
}

切换成OkHttp

新增依赖：这里的版本号，要跟io.github.openfeign:feign-core的版本，保持一致。

    io.github.openfeign
    feign-okhttp
    10.1.0

新增配置：

feign.httpclient.enabled=false
feign.okhttp.enabled=true