第一种：用HomeBrew下载Maven

1 . 先搜索一下有哪些Maven的版本

brew search maven

结果

==> Formulae
maven ✔                           maven-completion                  maven-shell                       maven@3.2                         maven@3.3                         maven@3.5
==> Casks
mavensmate                                                          homebrew/cask-fonts/font-maven-pro                                  homebrew/cask-fonts/font-maven-pro-vf-beta

2：选择一款合适的版本

brew install maven@3.5

3：成功

Updating Homebrew...
==> Downloading https://www.apache.org/dyn/closer.lua?path=maven/maven-3/3.5.4/binaries/apache-maven-3.5.4-bin.tar.gz
==> Downloading from https://mirrors.bfsu.edu.cn/apache/maven/maven-3/3.5.4/binaries/apache-maven-3.5.4-bin.tar.gz
######################################################################## 100.0%
==> Caveats
maven@3.5 is keg-only, which means it was not symlinked into /usr/local,
because this is an alternate version of another formula.

If you need to have maven@3.5 first in your PATH run:
  echo 'export PATH="/usr/local/opt/maven@3.5/bin:$PATH"' >> ~/.profile

==> Summary
🍺  /usr/local/Cellar/maven@3.5/3.5.4_1: 104 files, 10.2MB, built in 6 seconds

4:如果碰到没有权限写入某文件就用下面的

chmod 777 某文件