怎么安装参见CentOS6.9安装Nexus3.19 ，接下来就是如何配置。打开我们安装后的nexus界面，用admin账号登陆，点击Server administration and configuration按钮：
点击Repository
我们可以看到nexus默认给我建好了一些仓库，其中包括3类：代理proxy，仓库组group和宿主host。
代理用来指向远程仓库的，如中央仓库，但毕竟国内的阿里云仓库比国外要快许多，所以我们自己建一个新的代理仓库。点击Create Repository：
选择maven2(proxy)：
输入仓库名和阿里云的远程仓库地址(http://maven.aliyun.com/nexus/content/groups/public)：
拉到最下面点击Create Repository，返回上一层界面：
接着我们创建宿主仓库，宿主仓库跟我们的项目相关，用于上传我们打出来的包，分发布Release和快照Snapshot两种，所以我们就建两个宿主仓库，过程同上：
最后我们再创建一个仓库组，仓库组就像数据库的视图一样，能把多个仓库聚合起来用，记得把aliyun放在maven-central上面，这样才能优先找阿里云的构件：
ok，现在我要的仓库都弄好了，接着配置maven的全局设置setting.xml文件。在这之前，还得新建一个用户给开发用。nexus3.19的默认用户有两种：admin(能配置仓库、查询和上传构件)和anonymous(只能查构件)：
我们新增一个角色deployment用于构建查询和上传，剥离admin的仓库管理能力，免得开发人员瞎搞。先新增角色：
再回去用户那里新增一个deployment用户：
最后，我们在setting中添加我们新加的宿主仓库的认证(我设置deployment用户的密码就是deployment123)，配置镜像，让所有maven构建都走到镜像，经由镜像去请求仓库组，最后请求到我们配置的宿主仓库和代理仓库，大概脉络如下：
+---------------aliyun(proxy) ：下载开源jar包
maven -> nexus(group) -> |---------------nexus-releases(host) ：项目上传release的jar包，下载本地上传的jar包
+---------------nexus-snapshots(host)：项目上传snapshot的jar包，下载本地上传的jar包
新建一个setting文件setting_nexus.xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
<localRepository>E:/Users/wulf/.m2/repository</localRepository>
<mirrors>
<mirror>
<id>nexus</id>
<name>nexus repository</name>
<url>http://111.11.11.11/repository/nexus-group</url>
<mirrorOf>*</mirrorOf>
</mirror>
</mirrors>
<!-- 激活配置 -->
<activeProfiles>
<activeProfile>nexus</activeProfile>
</activeProfiles>
<profiles>
<profile>
<id>nexus</id>
<repositories>
<repository>
<id>central</id>
<url>http://111.11.11.11:17407/repository/aliyun</url>
<releases><enabled>true</enabled></releases>
<snapshots><enabled>true</enabled></snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>central</id>
<url>http://111.11.11.11:17407/repository/aliyun</url>
<releases><enabled>true</enabled></releases>
<snapshots><enabled>true</enabled></snapshots>
</pluginRepository>
</pluginRepositories>
</profile>
</profiles>
<servers>
<server>
<id>nexus-releases</id>
<username>deployment</username>
<password>deployment123</password>
</server>
<server>
<id>nexus-snapshots</id>
<username>deployment</username>
<password>deployment123</password>
</server>
</servers>
</settings>
新建一个maven项目(spring boot项目)，指定我们新增setting文件：
只需要往按默认生成的pom文件中加入上传jar包的宿主仓库即可：
<?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>2.3.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.wlf</groupId>
<artifactId>spring-cloud-plugin</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>spring-cloud-plugin</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</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>
<distributionManagement>
<repository>
<id>nexus-releases</id>
<url>http://111.11.11.11:17407/repository/nexus-releases/</url>
</repository>
<snapshotRepository>
<id>nexus-snapshots</id>
<url>http://111.11.11.11:17407/repository/nexus-snapshots/</url>
</snapshotRepository>
</distributionManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
跑一个deploy，看下maven执行日志：
Downloading: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/maven-metadata.xml
Uploading: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/spring-cloud-plugin-0.0.1-20201017.010507-1.jar
Uploaded: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/spring-cloud-plugin-0.0.1-20201017.010507-1.jar (8033 KB at 1523.3 KB/sec)
Uploading: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/spring-cloud-plugin-0.0.1-20201017.010507-1.pom
Uploaded: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/spring-cloud-plugin-0.0.1-20201017.010507-1.pom (3 KB at 4.9 KB/sec)
Downloading: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/maven-metadata.xml
Uploading: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/maven-metadata.xml
Uploaded: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/0.0.1-SNAPSHOT/maven-metadata.xml (776 B at 2.9 KB/sec)
Uploading: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/maven-metadata.xml
Uploaded: http://111.11.11.11:17407/repository/nexus-snapshots/com/wlf/spring-cloud-plugin/maven-metadata.xml (286 B at 1.4 KB/sec)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 27.136 s
[INFO] Finished at: 2020-10-17T09:05:13+08:00
[INFO] Final Memory: 25M/210M
[INFO] ------------------------------------------------------------------------
去看一眼nexus的界面，nexus-snapshots的包成功打上去了：
