Springcloud集成Nacos + Gateway

在上一文章中，创建了一个简单版玩，刚接触这个，写下自己集成过程，其实这章也完全是，照搬我以前集成Springcloud Eureka +Gateway，就是想看看以前的配置能不能在这用!

pom.xml

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.9.RELEASE
         
    
    com.example
    nacos_gateway
    0.0.1-SNAPSHOT
    war
    nacos_gateway
    Demo project for Spring Boot

    
        1.8
        Greenwich.SR3
    

    
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
        
        
            org.springframework.cloud
            spring-cloud-starter-gateway
        
        
        
            org.springframework.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
    

    
        
            
                org.springframework.cloud
                spring-cloud-dependencies
                ${spring-cloud.version}
                pom
                import
            
            
                org.springframework.cloud
                spring-cloud-alibaba-dependencies
                0.2.2.RELEASE
                pom
                import
            
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

需要注意在Gateway服务中的pom.xml文件中不要存在这个jar

        
            org.springframework.boot
            spring-boot-starter-tomcat
            provided
        

否则调用接口时会报以下错误因为gateway使用的是webflux,默认使用netty,所以从依赖中排除 tomcat相关的依赖

java.lang.ClassCastException: org.springframework.core.io.buffer.DefaultDataBufferFactory cannot be cast to org.springframework.core.io.buffer.NettyDataBufferFactory
	at org.springframework.cloud.gateway.filter.NettyWriteResponseFilter.lambda$filter$1(NettyWriteResponseFilter.java:82) ~[spring-cloud-gateway-core-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:44) [reactor-core-3.2.12.RELEASE.jar:3.2.12.RELEASE]

错误2 是由于 spring-boot-starter-web 引起

        
            org.springframework.boot
            spring-boot-starter-web
        

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'routeDefinitionRouteLocator' defined in class path resource [org/springframework/cloud/gateway/config/GatewayAutoConfiguration.class]: Unsatisfied dependency expressed through method 'routeDefinitionRouteLocator' parameter 4; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.core.convert.ConversionService' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Qualifier(value=webFluxConversionService)}
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:769) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:847) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:877) ~[spring-context-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.1.9.RELEASE.jar:2.1.9.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744) [spring-boot-2.1.9.RELEASE.jar:2.1.9.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391) [spring-boot-2.1.9.RELEASE.jar:2.1.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) [spring-boot-2.1.9.RELEASE.jar:2.1.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.1.9.RELEASE.jar:2.1.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204) [spring-boot-2.1.9.RELEASE.jar:2.1.9.RELEASE]
	at com.example.nacos_gateway.NacosGatewayApplication.main(NacosGatewayApplication.java:12) [classes/:na]
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.core.convert.ConversionService' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Qualifier(value=webFluxConversionService)}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1662) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1221) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1175) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760) ~[spring-beans-5.1.10.RELEASE.jar:5.1.10.RELEASE]
	... 19 common frames omitted

application.yml

server:
  port: 8087
spring:
  application:
    name: nacos_gateway
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
    gateway:
      discovery:
        locator:
          enabled: true  #表明gateway开启服务注册和发现的功能，并且spring cloud gateway自动根据服务发现为每一个服务创建了一个router，这个router将以服务名开头的请求路径转发到对应的服务
          lower-case-service-id: true  #是将请求路径上的服务名配置为小写（因为服务注册的时候，向注册中心注册时将服务名转成大写的了
      routes:
          -id: apiuser
          #
          uri: lb://nacos-consumer-user
          predicates:
          # http://localhost:6601/user/user/users/2, 必须加上StripPrefix=1，否则访问服务时会带上user
          - Path=/user/** # 转发该路径
           #以下是配置例子
            # - id: 163                     #网关路由到网易官网
            #  uri: http://www.163.com/
            #  predicates:
                - Path=/163/**
        #      - id: ORDER-SERVICE           #网关路由到订单服务order-service
        #        uri: lb://ORDER-SERVICE
        #        predicates:
        #          - Path=/ORDER-SERVICE/**
        #      - id: USER-SERVICE            #网关路由到用户服务user-service
        #        uri: lb://USER-SERVICE
        #        predicates:
        #          - Pach=/USER-SERVICE/**

启动类

package com.example.nacos_gateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class NacosGatewayApplication {

    public static void main(String[] args) {
        SpringApplication.run(NacosGatewayApplication.class, args);
    }

}

Gateway调用另外一个服务

package com.example.nacos_client_user.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;

import java.net.URL;

@RestController
@RequestMapping(value = "/user")
public class UserController {

    @Autowired
    private LoadBalancerClient loadBalancerClient;

    //通过RestTemplate
    @RequestMapping(value = "/getConsumer",method = RequestMethod.GET)
    public String getConsumer(@RequestParam(value = "username") String username){
        // 通过spring cloud client中的负载均衡接口选取服务提供节点实现接口调用
        // serviceId为spring.application.name
        System.out.println(username);
        ServiceInstance serviceInstance = loadBalancerClient.choose("nacos");
        System.out.println(serviceInstance.getUri());
        String url = serviceInstance.getUri()+"/server/getServerString?username="+username;
        RestTemplate restTemplate = new RestTemplate();
        String result =restTemplate.getForObject(url,String.class);
        return "URL :"+ url + "返回参数 ："+result;
    }
}