本篇内容主要讲解“spring cloud中RetryableFeignLoadBalancer的作用是什么”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“spring cloud中RetryableFeignLoadBalancer的作用是什么”吧!
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本文主要研究一下spring cloud的RetryableFeignLoadBalancer
spring-cloud-openfeign-core-2.2.0.M1-sources.jar!/org/springframework/cloud/openfeign/ribbon/RetryableFeignLoadBalancer.java
public class RetryableFeignLoadBalancer extends FeignLoadBalancer
implements ServiceInstanceChooser {
private final LoadBalancedRetryFactory loadBalancedRetryFactory;
public RetryableFeignLoadBalancer(ILoadBalancer lb, IClientConfig clientConfig,
ServerIntrospector serverIntrospector,
LoadBalancedRetryFactory loadBalancedRetryFactory) {
super(lb, clientConfig, serverIntrospector);
this.loadBalancedRetryFactory = loadBalancedRetryFactory;
this.setRetryHandler(new DefaultLoadBalancerRetryHandler(clientConfig));
}
@Override
public RibbonResponse execute(final RibbonRequest request,
IClientConfig configOverride) throws IOException {
final Request.Options options;
if (configOverride != null) {
RibbonProperties ribbon = RibbonProperties.from(configOverride);
options = new Request.Options(ribbon.connectTimeout(this.connectTimeout),
ribbon.readTimeout(this.readTimeout));
}
else {
options = new Request.Options(this.connectTimeout, this.readTimeout);
}
final LoadBalancedRetryPolicy retryPolicy = this.loadBalancedRetryFactory
.createRetryPolicy(this.getClientName(), this);
RetryTemplate retryTemplate = new RetryTemplate();
BackOffPolicy backOffPolicy = this.loadBalancedRetryFactory
.createBackOffPolicy(this.getClientName());
retryTemplate.setBackOffPolicy(
backOffPolicy == null ? new NoBackOffPolicy() : backOffPolicy);
RetryListener[] retryListeners = this.loadBalancedRetryFactory
.createRetryListeners(this.getClientName());
if (retryListeners != null && retryListeners.length != 0) {
retryTemplate.setListeners(retryListeners);
}
retryTemplate.setRetryPolicy(retryPolicy == null ? new NeverRetryPolicy()
: new FeignRetryPolicy(request.toHttpRequest(), retryPolicy, this,
this.getClientName()));
return retryTemplate.execute(new RetryCallback() {
@Override
public RibbonResponse doWithRetry(RetryContext retryContext)
throws IOException {
Request feignRequest = null;
// on retries the policy will choose the server and set it in the context
// extract the server and update the request being made
if (retryContext instanceof LoadBalancedRetryContext) {
ServiceInstance service = ((LoadBalancedRetryContext) retryContext)
.getServiceInstance();
if (service != null) {
feignRequest = ((RibbonRequest) request
.replaceUri(reconstructURIWithServer(
new Server(service.getHost(), service.getPort()),
request.getUri()))).toRequest();
}
}
if (feignRequest == null) {
feignRequest = request.toRequest();
}
Response response = request.client().execute(feignRequest, options);
if (retryPolicy != null
&& retryPolicy.retryableStatusCode(response.status())) {
byte[] byteArray = response.body() == null ? new byte[] {}
: StreamUtils
.copyToByteArray(response.body().asInputStream());
response.close();
throw new RibbonResponseStatusCodeException(
RetryableFeignLoadBalancer.this.clientName, response,
byteArray, request.getUri());
}
return new RibbonResponse(request.getUri(), response);
}
}, new LoadBalancedRecoveryCallback() {
@Override
protected RibbonResponse createResponse(Response response, URI uri) {
return new RibbonResponse(uri, response);
}
});
}
@Override
public RequestSpecificRetryHandler getRequestSpecificRetryHandler(
FeignLoadBalancer.RibbonRequest request, IClientConfig requestConfig) {
return new RequestSpecificRetryHandler(false, false, this.getRetryHandler(),
requestConfig);
}
@Override
public ServiceInstance choose(String serviceId) {
return new RibbonLoadBalancerClient.RibbonServer(serviceId,
this.getLoadBalancer().chooseServer(serviceId));
}
} RetryableFeignLoadBalancer继承了FeignLoadBalancer，实现了ServiceInstanceChooser接口
其构造器根据clientConfig创建了DefaultLoadBalancerRetryHandler；其choose方法使用的是getLoadBalancer().chooseServer，最后通过RibbonLoadBalancerClient.RibbonServer包装返回
其execute方法首先创建了LoadBalancedRetryPolicy，进而创建retryTemplate，最后通过retryTemplate.execute来实现重试功能；其RetryCallback的doWithRetry方法在retryContext是LoadBalancedRetryContext的条件下会切换下一个service实例来进行重试
RetryableFeignLoadBalancer继承了FeignLoadBalancer，对execute方法使用retryTemplate来实现重试，其中在retryContext是LoadBalancedRetryContext的条件下会切换下一个service实例来进行重试
到此，相信大家对“spring cloud中RetryableFeignLoadBalancer的作用是什么”有了更深的了解，不妨来实际操作一番吧！这里是创新互联网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
