Zuul回退机制

默认情况下，经过Zuul的请求都会使用Hystrix进行包裹，所以Zuul本身就具有断路器的功能。

未指定路由配置回退

• 代码示例如下：

package com.mmzs.cloud.fallback;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;
import com.netflix.hystrix.exception.HystrixTimeoutException;
/**
* @author: mmzsit
* @date:
2018年11月14日
* @Description: 用于定制FallBack返回的body、状态码、消息头Header
* 博客地址：https://blog.csdn.net/MobiusStrip
* @version V1.0
*/
@Component
public class MyFallbackProvider implements FallbackProvider {
@Override
public String getRoute() {
return "microservice-provider-user";
//微服务配了路由的话，就用配置的名称
//return "customers";
//如果要为所有路由提供默认回退，可以创建FallbackProvider类型的bean并使getRoute方法返回*或null
//return "*";
}
@Override
public ClientHttpResponse fallbackResponse(String route, final Throwable cause) {
if (cause instanceof HystrixTimeoutException) {
return response(HttpStatus.GATEWAY_TIMEOUT);
} else {
return response(HttpStatus.INTERNAL_SERVER_ERROR);
}
}
private ClientHttpResponse response(final HttpStatus status) {
return new ClientHttpResponse() {
@Override
public HttpStatus getStatusCode() throws IOException {
//return status;
return HttpStatus.BAD_REQUEST;
}
@Override
public int getRawStatusCode() throws IOException {
//return status.value();
return HttpStatus.BAD_REQUEST.value();
}
@Override
public String getStatusText() throws IOException {
//return status.getReasonPhrase();
//return HttpStatus.BAD_REQUEST.name();
return HttpStatus.BAD_REQUEST.getReasonPhrase();
}
@Override
public void close() {
}
@Override
public InputStream getBody() throws IOException {
return new ByteArrayInputStream(("fallback:"+MyFallbackProvider.this.getRoute()).getBytes());
}
@Override
public HttpHeaders getHeaders() {
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
return headers;
}
};
}
}
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==[注]== 其中代理的路由如果在 application.yml中配置过，也可以有如下示例：

zuul:
routes:
customers: /myuser/**
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为所有路由提供默认回退 

如果要为所有路由提供默认回退，可以创建FallbackProvider类型的bean并使getRoute方法返回*或null

• 代码示例如下：

class MyFallbackProvider implements FallbackProvider {
@Override
public String getRoute() {
return "*";
}
@Override
public ClientHttpResponse fallbackResponse(String route, Throwable throwable) {
return new ClientHttpResponse() {
@Override
public HttpStatus getStatusCode() throws IOException {
return HttpStatus.OK;
}
@Override
public int getRawStatusCode() throws IOException {
return 200;
}
@Override
public String getStatusText() throws IOException {
return "OK";
}
@Override
public void close() {
}
@Override
public InputStream getBody() throws IOException {
return new ByteArrayInputStream("fallback".getBytes());
}
@Override
public HttpHeaders getHeaders() {
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
return headers;
}
};
}
}
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