04.Zuul熔断

zuul是一个代理服务，但如果被代理的服务突然断了，这个时候zuul上面会有出错信息，例如，停止product服务

访问：http://localhost:9501/enjoy-api/product-proxy/prodcut/get/1

现在服务的调用方已经做了处理，不会出现这样的错误信息，但一般来说，对于zuul本身代理方，也应该进行zuul的降级处理

修改【microcloud-zuul-gateway】建立fallback回退处理类
package cn.enjoy.fallback;


import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

@Component
public class ProviderFallback implements FallbackProvider {
@Override
public String getRoute() {
return ““;
}

@Override
public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
return new ClientHttpResponse() {

@Override
public HttpHeaders getHeaders() {
HttpHeaders headers = new HttpHeaders() ;
headers.set(“Content-Type”, “text/html; charset=UTF-8”);
return headers;
}

@Override
public InputStream getBody() throws IOException {
// 响应体
return new ByteArrayInputStream(“产品微服务不可用，请稍后再试。”.getBytes());
}

@Override
public HttpStatus getStatusCode() throws IOException {
return HttpStatus.BAD_REQUEST;
}

@Override
public int getRawStatusCode() throws IOException {
return HttpStatus.BAD_REQUEST.value();
}

@Override
public String getStatusText() throws IOException {
return HttpStatus.BAD_REQUEST.getReasonPhrase();
}

@Override
public void close() {

}
};
}
}


访问：http://localhost:9501/enjoy-api/product-proxy/prodcut/get/1

getRoute：方法可以返回服务的ID，比如‘microcloud-provider-product’，如果需要匹配全部适应 “”