SpringCloudAlibaba整合SpringCloudGateway问题

其实我以前一直没有理解为什么需要网关，我觉得使用nginx就可以了，后来我发现很多服务后台的权限管理比较弱，例如flink、nacos这些，所以需要网关鉴权。

不多说开始的时候用的版本：

<spring-cloud.version>2020.0.4</spring-cloud.version>
<spring-cloud-alibaba.version>2.2.6.RELEASE</spring-cloud-alibaba.version>

问题一：负载均衡

Description:

Parameter 0 of method loadBalancerWebClientBuilderBeanPostProcessor in org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration required a bean of type 'org.springframework.cloud.client.loadbalancer.reactive.DeferringLoadBalancerExchangeFilterFunction' that could not be found.


Action:

Consider defining a bean of type 'org.springframework.cloud.client.loadbalancer.reactive.DeferringLoadBalancerExchangeFilterFunction' in your configuration.

两种解决方案：

去掉alibaba模块ribbon

<dependency>
	<groupId>com.alibaba.cloud</groupId>
	<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
	<exclusions>
		<exclusion>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
		</exclusion>
	</exclusions>
</dependency>

添加新版负载均衡

<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>

问题二：为什么冲突

这里有个问题就是为什么alibaba服务发现里面需要网飞的负载均衡模块，实在是想不通。

于是我去看了阿里巴巴最新版本，然后发现已经没有这个模块了，然后选择两个版本中spring版本也一样，这样冲突就会少很多：

<spring-cloud.version>2020.0.1</spring-cloud.version>
<spring-cloud-alibaba.version>2021.1</spring-cloud-alibaba.version>

但是又会提示：

- Change Spring Boot version to one of the following versions [2.3.x, 2.4.x] .
You can find the latest Spring Boot versions here [https://spring.io/projects/spring-boot#learn]. 
If you want to learn more about the Spring Cloud Release train compatibility, you can visit this page [https://spring.io/projects/spring-cloud#overview] and check the [Release Trains] section.
If you want to disable this check, just set the property [spring.cloud.compatibility-verifier.enabled=false]

这是因为我们的SpringBoot版本和SpringCloud不匹配，修改SpringBoot版本。

完美版本pom.xml

<?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>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.4.2</version>
		<relativePath />
	</parent>

	<groupId>com.acgist</groupId>
	<artifactId>asc-gateway</artifactId>
	<version>1.0.0</version>
	<name>asc-gateway</name>
	<description>asc-gateway</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>2020.0.1</spring-cloud.version>
		<spring-cloud-alibaba.version>2021.1</spring-cloud-alibaba.version>
	</properties>

	<dependencies>
		<!-- 解决无法加载bootstrap问题 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-bootstrap</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-gateway</artifactId>
		</dependency>
		<!-- LB：负载均衡 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-loadbalancer</artifactId>
		</dependency>

		<!--
		<dependency>
			<groupId>com.alibaba.csp</groupId>
			<artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
		</dependency>
		-->
		<dependency>
			<groupId>com.alibaba.cloud</groupId>
			<artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
		</dependency>
		<dependency>
			<groupId>com.alibaba.cloud</groupId>
			<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>${spring-cloud.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
			<dependency>
				<groupId>com.alibaba.cloud</groupId>
				<artifactId>spring-cloud-alibaba-dependencies</artifactId>
				<version>${spring-cloud-alibaba.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

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

</project>

这个东西就像：SpringCloudAlibaba依赖SpringCloud，然后SpringCloud依赖SpringBoot，所以有意思的就是一个版本比一个版本低。