Maven 镜像配置

创建全局配置文件~/.m2/settings.xml：

<?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">
    <mirrors>
        <!-- 阿里云仓库 -->
        <mirror>
            <id>alimaven</id>
            <mirrorOf>central</mirrorOf>
            <name>aliyun maven</name>
            <url>http://maven.aliyun.com/nexus/content/repositories/central/</url>
        </mirror>
        <!-- 中央仓库 1 -->
        <mirror>
            <id>repo1</id>
            <mirrorOf>central</mirrorOf>
            <name>Human Readable Name for this Mirror.</name>
            <url>http://repo1.maven.org/maven2/</url>
        </mirror>
        <!-- 中央仓库 2 -->
        <mirror>
            <id>repo2</id>
            <mirrorOf>central</mirrorOf>
            <name>Human Readable Name for this Mirror.</name>
            <url>http://repo2.maven.org/maven2/</url>
        </mirror>
    </mirrors>
</settings>

Gradle 镜像配置

对当前项目生效

编辑当前项目中的 build.gradle 文件：

buildscript {
    repositories {
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter'}
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter'}
    }
}

对所有项目生效

创建~/.gradle/init.gradle 文件：

allprojects{
    repositories {
        def ALIYUN_REPOSITORY_URL = 'http://maven.aliyun.com/nexus/content/groups/public'
        def ALIYUN_JCENTER_URL = 'http://maven.aliyun.com/nexus/content/repositories/jcenter'
        all { ArtifactRepository repo ->
            if(repo instanceof MavenArtifactRepository){
                def url = repo.url.toString()
                if (url.startsWith('https://repo1.maven.org/maven2')) {
                    project.logger.lifecycle "Repository {repo.url} replaced byALIYUN_REPOSITORY_URL."
                    remove repo
                }
                if (url.startsWith('https://jcenter.bintray.com/')) {
                    project.logger.lifecycle "Repository {repo.url} replaced byALIYUN_JCENTER_URL."
                    remove repo
                }
            }
        }
        maven {
            url ALIYUN_REPOSITORY_URL
            url ALIYUN_JCENTER_URL
        }
    }
}

多版本 JDK 配置

安装最新的 JDK 13：

$ brew install java
$ sudo ln -sfn /usr/local/opt/openjdk/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk.jdk
# JAVA_HOME = /Library/Java/JavaVirtualMachines/openjdk.jdk

由于 Oracle 已经移除了 JDK 8 的公开下载链接，因此 HomeBrew 不支持直接安装 JDK 8 了，但可以安装 adoptopenjdk，此项目将继续维护 JDK 8 至 2023 年：

$ brew tap adoptopenjdk/openjdk
$ brew cask install adoptopenjdk8

maven-compiler-plugin 插件

在 IDEA 中切换 JDK 的版本，如果是 Maven 项目，会出现即使更改了 IDEA 中 JDK 相关设置，编译仍然会报错。

IDEA maven Error:java: release version 5 not supported

在 pom.xml 中引入 maven-compiler-plugin 插件：

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <!-- JDK 8 -->
            <!-- <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration> -->

            <!-- JDK 11 -->
            <configuration>
                <source>11</source>
                <target>11</target>
            </configuration>
        </plugin>
    </plugins>
</build>