Spring Cloud Alibaba 从零搭建(一) ---NACOS配置中心

@[TOC](Spring Cloud Alibaba 从零搭建(一) —NACOS配置中心)

前言

整体入口：
https://blog.youkuaiyun.com/lwb314/article/details/108277732

快速搭建

1. 构建工具地址:http://start.aliyun.com
   因为是从头开始搭建，所以我们要先做配置，只引入一个
   nacos config
   

POM.XML配置

pom.xml是自动生成就可以这里贴出来如下：

<?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>
    <groupId>com.lwb.demo</groupId>
    <artifactId>dubbo-test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-test</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
        <spring-cloud-alibaba.version>2.2.2.RELEASE</spring-cloud-alibaba.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>com.lwb.demo.dubbotest.DubboTestApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

启动类

package com.lwb.demo.dubbotest;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DubboTestApplication {

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

}

开始使用NACOS

1.创建文件bootstrap.yml，之前的bootstrap.properties和application.properties都删除，yml比是比properties新的配置格式，有一些新的用法，后续用到会介绍。
这里为什么创建的是bootstrap.yml，而不是application.yml，因为bootstrap是在spring boot框架加载前进行加载的，而spring boot以及后续的dubbo配置都直接使用nacos了，所以配置中心的地址等信息要写在bootstrap.yml配置里

2.直接启动主函数看报错

问题1:
提示配置没生效，因为我们还什么都没配

2021-08-13 13:57:16.334 ERROR 2240 --- [           main] c.a.n.c.config.http.ServerHttpAgent      : [NACOS SocketTimeoutException httpGet] currentServerAddr:http://localhost:8848， err : connect timed out
2021-08-13 13:57:16.334 ERROR 2240 --- [           main] c.a.n.c.config.http.ServerHttpAgent      : no available server
2021-08-13 13:57:16.341 ERROR 2240 --- [           main] c.a.n.client.config.impl.ClientWorker    : [fixed-localhost_8848] [sub-server] get server config exception, dataId=null.properties, group=DEFAULT_GROUP, tenant=

java.net.ConnectException: no available server

问题1从日志上看连的是localhost:8848，而实际我的服务在服务器上，所以先添加nacos配置中心的配置。

spring:
  cloud:
    nacos:
      config:
        server-addr: 10.10.10.230:8848

问题2：

2021-08-13 14:07:35.799  INFO 14316 --- [           main] c.a.nacos.client.config.impl.CacheData   : [fixed-10.10.10.230_8848] [add-listener] ok, tenant=, dataId=null.properties, group=DEFAULT_GROUP, cnt=1

报错2：
提示没有spring.application.name，那么我们配一下

java.lang.IllegalArgumentException: Could not resolve placeholder 'spring.application.name' in value "${spring.application.name}"

解决方式，加入配置

spring:
  application:
    name: dubbo_test_demo

报错3：
明显提示程序再注册我本地的8848端口，但是nacos是在服务器上，所以继续添加配置

com.alibaba.nacos.api.exception.NacosException: failed to req API:/nacos/v1/ns/instance/list after all servers([localhost:8848])