为Zuul添加回退

一 简介

想要为Zuul添加回退，需要实现ZuulFallbackProvider接口。在实现类中，指定为哪个微服务提供回退，并提供了一个ClientHttpResponse作为回退响应。

二 实战

1 新建项目microservice-gateway-zuul-fallback

2 编写Zuul的回退类

package com.itmuch.cloud.study.fallback;

import org.springframework.cloud.netflix.zuul.filters.route.ZuulFallbackProvider;
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 java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;

@Component
public class UserFallbackProvider implements ZuulFallbackProvider {
  @Override
  public String getRoute() {
    // 表明是为哪个微服务提供回退
    return "microservice-provider-user";
  }

  @Override
  public ClientHttpResponse fallbackResponse() {
    return new ClientHttpResponse() {
      @Override
      public HttpStatus getStatusCode() throws IOException {
        // fallback时的状态码
        return HttpStatus.OK;
      }

      @Override
      public int getRawStatusCode() throws IOException {
        // 数字类型的状态码，本例返回的其实就是200，详见HttpStatus
        return this.getStatusCode().value();
      }

      @Override
      public String getStatusText() throws IOException {
        // 状态文本，本例返回的其实就是OK，详见HttpStatus
        return this.getStatusCode().getReasonPhrase();
      }

      @Override
      public void close() {
      }

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

      @Override
      public HttpHeaders getHeaders() {
        // headers设定
        HttpHeaders headers = new HttpHeaders();
        MediaType mt = new MediaType("application","json", Charset.forName("UTF-8"));
        headers.setContentType(mt);

        return headers;
      }
    };
  }
}

三 测试

1 启动eureka

2 启动项目microservice-gateway-zuul-fallback

3 启动Dashboard微服务

4 访问user用户微服务 http://localhost:8040/microservice-provider-user/1