SpringCloud之Zuul网关[通俗易懂]

全栈程序员站长

发布于 2022-09-22 20:14:29

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发布于 2022-09-22 20:14:29

文章被收录于专栏：全栈程序员必看

大家好，又见面了，我是你们的朋友全栈君。

1、zuul网关服务

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>com.yzm</groupId>
        <artifactId>springcloud</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>

    <artifactId>zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>zuul</name>
    <description>Demo project for Spring Boot</description>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

启动类 @EnableZuulProxy：启用zuul网关代理

@EnableZuulProxy
@EnableEurekaClient
@SpringBootApplication
public class ZuulApplication { 
   
	。。。
}

application.yml

server:
  port: 8096

spring:
  application:
    name: service-zuul

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8088/eureka/

zuul:
  routes:
    ribbon-ha: /api-a/** ribbon-hi: path: /api-b/** feign_haha: serviceId: feign-ha path: /api-c/**

路由规则：请求url带有 /api-a/ 的路由到 ribbon-ha 服务(spring.application.name) 请求url带有 /api-b/ 的路由到 ribbon-hi 服务请求url带有 /api-c/ 的路由到 feign-ha 服务(feign_haha 别名)

2、路由转发

依次启动 eureka、zuul、ribbon-ha、ribbon-hi、feign-ha、feign-hi

http://localhost:8096/api-a/hello?name=yzm

http://localhost:8096/api-b/hello?name=yzm

http://localhost:8096/api-c/hello?name=yzm

配置文件中zuul没有配置feign-hi的路由，但zuul有个默认路由规则即：zuul_ip:zuul_post/service_id/url http://localhost:8096/feign-hi/hello?name=yzm

所有请求都可以通过zuul正确路由到对应的服务上

二级路由 http://localhost:8096/api-a/ha?name=yzm

转发完成！

再启动ribbon-hi:18093 刷新

负载均衡！

3、zuul配置

url

zuul:
  routes:
    ribbon-ha: /api-a/** ribbon-hi: path: /api-b/** # feign_haha: # serviceId: feign-ha # path: /api-c/** feign_haha: path: /api-c/** # 转发到IP地址 url: http://localhost:8094/ baidu: path: /baidu/** # 转发到域名 url: https://www.baidu.com/

http://localhost:8096/api-c/hello?name=yzm

http://localhost:8096/baidu/

虽然url也可以进行转发但是无法进行负载均衡，推荐使用serviceId进行配置

ignored

zuul:
  ignored-services: '*'
  ignored-patterns: /**/hello/** routes: ribbon-ha: /api-a/** ribbon-hi: path: /api-b/** feign_haha: serviceId: feign-ha path: /api-c/**

ignored-services：忽略服务，只接受routes列表中的服务，默认规则的IP:PORT/serviceid/这种就无法转发 ignored-patterns: 忽略请求中带有hello的转发

prefix

zuul:
  prefix: /yzm
  # 对所有服务有效
  # stripPrefix: false
  routes:
    ribbon-ha: /api-a/** ribbon-hi: path: /api-b/** feign_haha: serviceId: feign-ha path: /api-c/** # 只对feign-ha服务有效 stripPrefix: false

prefix：带有前缀的请求才会被拦截 stripPrefix：默认true，增加的前缀在转发之前剔除，false不剔除

没有前缀不拦截

多了前缀，没有对应接口，访问失败

4、回调

zuul:
  ignored-services: '*'
  routes:
    ribbon-ha: /api-a/** ribbon-hi: path: /api-b/** feign_haha: serviceId: feign-ha path: /api-c/**

拦截api-a请求路由到ribbon-ha时，ribbon-ha服务挂了，此时显示

编写回调

package com.yzm.zuul.filter;

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.StandardCharsets;

@Component
public class MyFallbackProvider implements FallbackProvider { 
   

    @Override
    public String getRoute() { 
   
        // 服务id，如果需要所有调用都支持回退，则return "*"或return null
        return "ribbon-ha";
    }

    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) { 
   
        return new ClientHttpResponse() { 
   
            @Override
            public HttpStatus getStatusCode() throws IOException { 
   
                return HttpStatus.OK;
            }

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

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

            @Override
            public void close() { 
   

            }

            @Override
            public InputStream getBody() throws IOException { 
   
                String msg = route + ": 服务异常";
                return new ByteArrayInputStream(msg.getBytes(StandardCharsets.UTF_8));
            }

            @Override
            public HttpHeaders getHeaders() { 
   
                HttpHeaders headers = new HttpHeaders();
                headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
                return headers;
            }
        };
    }
}

重启zuul，再次访问

5、过滤器

filterType：返回一个字符串代表过滤器的类型，在zuul中定义了四种不同生命周期的过滤器类型，具体如下：
- pre：路由之前
- routing：路由之时
- post：路由之后
- error：发送错误调用
filterOrder：过滤的顺序，数值越小优先级越高
shouldFilter：这里可以写逻辑判断，是否要过滤，本文true,永远过滤。
run：过滤器的具体逻辑。可用很复杂，包括查sql，nosql去判断该请求到底有没有权限访问。

package com.yzm.zuul.filter;

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.netflix.zuul.filters.support.FilterConstants;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;

@Slf4j
@Component
public class MyFilter extends ZuulFilter { 
   
    @Override
    public String filterType() { 
   
        return FilterConstants.PRE_TYPE;
    }

    @Override
    public int filterOrder() { 
   
        return FilterConstants.PRE_DECORATION_FILTER_ORDER - 1;
    }

    @Override
    public boolean shouldFilter() { 
   
        return true;
    }

    @Override
    public Object run() throws ZuulException { 
   
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        log.info(String.format("%s >>> %s", request.getMethod(), request.getRequestURL().toString()));
        Object accessToken = request.getParameter("token");
        if (accessToken == null) { 
   
            log.warn("token is empty");
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(401);
            try { 
   
                ctx.getResponse().getWriter().write("token is empty");
            } catch (Exception e) { 
   
                //
            }
            return null;
        }
        log.info("ok");
        return null;
    }
}

上面的过滤器要求，请求中必须带有token参数重启zuul，不带token访问