分布式04-Spring Cloud Zuul 三 Fallback 回退机制

关于Zuul前2篇

回退机制只有针对于服务出现故障，Zuul做的一些后续操作。

代码

package com.cloud.config;


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 java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;

@Component
public class TestFallbackProvider implements FallbackProvider {

    @Override
    public String getRoute() {
        //处理所有的服务
//        return "*";
        // 表明是为哪个微服务提供回退，*表示为所有微服务提供回退
        return "eureka-server";
    }

    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        //回退时的HTTP Status Code
        return this.response(HttpStatus.NOT_FOUND);
    }

    private ClientHttpResponse response(final HttpStatus status) {
        return new ClientHttpResponse() {

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

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

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

            @Override
            public void close() {
            }

            @Override
            public InputStream getBody() throws IOException {

                //回退操作
                return new ByteArrayInputStream("eureka-server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;
            }

        };
    }

}

application.properties

zuul.routes.eureka-server.path=/public/*
zuul.routes.eureka-server.service-id=eureka-server
server.port= 12003
eureka.instance.hostname=localhost
eureka.client.service-url.defaultZone= http://${eureka.instance.hostname}:12000/eureka/
eureka.client.healthcheck.enabled=true
spring.application.name=eureka-Zuul

启动Zuul 和测试用的2个应用，打开Eureka，我们看到2个提供服务的应用eureka-server

eureka-server 提供一个返回端口的接口

/**
 * http://localhost:12001/public/getPort
 * @param pageable
 * @return
 * @throws Exception
 */
@RequestMapping(value = "/getPort", method = RequestMethod.GET )
public Msg getport(Pageable pageable, String operatorId) throws  Exception{
    return Msg.MsgSuccess(port);
}